JP2003018876A - Resonant inverter device - Google Patents

Abstract

(57) [Problem] To provide a resonance-type inverter device with less loss and higher efficiency than before. SOLUTION: In an inverter device having an inverter circuit 2A, a resonance circuit 2B and a control circuit 3, a three-phase main circuit, capacitors C1 to C6, load current sensors Is1 to Is3, and terminal voltage sensors Vs1 to Vs are provided in the inverter circuit.
6, a resonance circuit is provided with a three-phase auxiliary circuit, an inductance Lr, and a resonance current sensor Is4, and a zero voltage detection means 8, a resonance current arrival determination means 7, a drive signal generation means 6, and a main switching element are provided in a control circuit. Current conduction device determination means 16U, 16V, 16W for determining which of the Q1 to Q6 or the diodes D1 to D6 the current flows.
And a drive signal generating means for preventing generation of auxiliary drive signals S7 to S12 for turning on auxiliary switching elements Q7 to Q12 when the main switching element is turned off when a current is flowing through the main switching element. Operation inhibiting means 17 is provided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electric vehicle (E
V), a hybrid inverter (HEV), etc., and a resonance type inverter device that performs soft switching for driving a motor.

[0002]

2. Description of the Related Art FIG. 6 is a circuit diagram showing a configuration of a conventional soft switching inverter, which is generally an auxiliary resonance arm link snubber system (Auxiliary Reso).
ant Commuted Pole: ARCP
Method).

The soft switching inverter shown in FIG. 6 has, for example, an IG to which a motor 101 composed of a three-phase induction motor or a DC brushless motor is connected as a load.
BT (Insulated Gate Bipolar Transistor) is composed of an inverter section using Q101 to Q106 as switching elements.

The inverter section is formed by connecting IGBTs Q101 to Q106 to both ends of a DC power supply 103 in a three-phase bridge structure composed of U phase, V phase and W phase.
Between the collector terminal and the emitter terminal of the GBT, the motor 1
For the purpose of circulating the regenerative energy generated by an inductive load such as, and the current energy stored in the inductive load,
Free wheeling diode (FWD) D1
01 to D106 are connected. Further, between the collector terminal and the emitter terminal of each IGBT, buffer capacitors C101 to C106 for absorbing a surge voltage applied between the collector terminal and the emitter terminal of the IGBT when the IGBT is turned on or off are also connected. It

Further, the inverter section has a DC power source 103.
Is connected to both ends of the smoothing capacitor C109, and U is connected to the connection point of the midpoint voltage holding capacitors C107 and C108 connected in series to both ends of the smoothing capacitor C109.
Connection point between phase buffer capacitors C101 and C102, V
Connection point between phase buffer capacitors C103 and C104, W
From each of the connection points of the phase buffer capacitors C105 and C106, an inductance L101 resonating with the buffer capacitors C101 and C102, and a buffer capacitor C1.
03 and C104, an inductance L102 that resonates with the buffer capacitors C105 and C106, and an inductance L103 that resonates with the buffer capacitors C105 and C106, and a bidirectional switch unit SU10 for passing a resonance current through the inductance.
1 to SU 103 are connected.

In the soft switching inverter having the above-mentioned configuration, for example, when the IGBT Q101 is turned off and the IGBT Q102 is to be turned on after a short delay, the charging current of the buffer capacitor C101 and the discharging current of the buffer capacitor C102 are the inductance L101.
Through the middle point voltage holding capacitors C107, C108
To the buffer capacitors C104 and C10 for turning off the IGBTs Q104 and Q106 at the same time and turning on the IGBTs Q103 and Q105 after a short delay.
The charging current of 6 and the discharging current of the buffer capacitors C103 and C105 are supplied from the midpoint voltage holding capacitors C107 and C108 through the inductances L102 and L103.

Therefore, when the IGBT is turned off and the buffer capacitor is charged by charging / discharging the buffer capacitor by the resonance current of the buffer capacitor and the inductance, the time constant given by the buffer capacitor depends on the time constant. Due to the delay in the rise of the voltage applied to the IGBT, ZVS (Zero Voltage Switching) of the IGBT is realized, and conversely, when the buffer capacitor is discharged before the IGBT is turned on, the commutation diode becomes conductive. By doing so, the voltage and current applied to the IGBT become zero, so the ZVS (Ze
Since ro voltage switching (Zero current switching) and ZCS (Zero current Switching) are realized, turn-off of switching elements,
Alternatively, the loss generated at turn-on can be reduced.

FIG. 7 shows a conventional soft switching inverter, which is also called an auxiliary resonance AC link type inverter.

The soft switching inverter shown in FIG. 7 has commutation diodes D101 to D1 at both ends of the DC power source 103, as in the soft switching inverter shown in FIG.
06 and the buffer capacitors C101 to C106 are connected to each other, the IGBT Q101 to Q106 is connected to a three-phase bridge structure composed of U-phase, V-phase, W-phase, the inverter section,
U-phase buffer capacitors C101 and C1 in the inverter section
02 connection point, V-phase buffer capacitors C103 and C1
04 connection point, W-phase buffer capacitors C105 and C1
Between each of the 06 connection points, a buffer capacitor C1
01, C102 resonating with inductance L104, buffer capacitors C103, C104 resonating with inductance L105, buffer capacitors C105, C106
Each of the inductances L106 that resonate with each other and the bidirectional switch units SU104 to SU106 for flowing a resonance current through the inductances are connected.

The operation difference between the soft switching inverter shown in FIG. 6 and the soft switching inverter shown in FIG.
The IGBTs, which are switching elements, are ZVS and ZC only with the difference in the current path for charging and discharging the buffer capacitor.
The principle of reaching S is the same.

In the above soft switching inverter, the resonance current is always kept constant regardless of the magnitude of the load current, and the resonance circuit is always operated at the time of switching without distinction between turn-on and turn-off.

FIG. 8 is a circuit diagram showing a configuration of a collective resonance snubber inverter device in which the conventional soft switching inverter described above is improved and the number of resonance inductances is reduced to one.

In this inverter device, six inter-terminal voltage sensors Vs1 to Vs6 for detecting inter-terminal voltages V1 to V6 of the main switching elements Q1 to Q6, and terminals detected by these inter-terminal voltage sensors Vs1 to Vs6. Voltage V1
Zero voltage detection means 8 for detecting whether V6 is zero, and a resonance current I flowing through the resonance inductance Lr.
Resonant current sensor Is4 for detecting 4 and motor (load)
The load current sensors Is1, Is2, Is3 for detecting the load currents I1, I2, I3 flowing in 1 and the resonance current I4 are
The resonance current arrival determination means 7 for determining whether or not the load currents I1, I2, I3 are larger than the maximum value is required.

In the collective resonance snubber inverter device described above, the resonance circuit is operated in both the turn-on operation and the turn-off operation during switching of the main switching element. That is, the resonance inductance and
The resonant capacitor connected in parallel with the switching element and the main switching element resonated at turn-on and turn-off.

Here, in order to explain a specific operation,
The notation of voltage and current of each part and ON / OFF of each switching element in the circuit diagram of FIG. 8 will be defined first. First,
Regarding the voltage and current of each part, (1) the voltage with the collector side of Q1 applied to both ends of the parallel circuit of the main switching element Q1, the commutation diode D1, and the buffer capacitor C1 in the positive direction is V1, and similarly (2 ) A voltage applied to both ends of the parallel circuit of Q2, D2, C2 and having the collector side of Q2 in the positive direction is V2, (3) A collector side of Q3 applied to both ends of the parallel circuit of Q3, D3, C3 is in the positive direction. The voltage is V3,
(4) Q4 added to both ends of the parallel circuit of Q4, D4, and C4
The voltage with the collector side of the positive direction being V4, (5) Q5,
A voltage applied to both ends of the parallel circuit of D5 and C5 and having the collector side of Q5 in the positive direction is V5, (6) A voltage applied to both ends of the parallel circuit of Q6, D6, and C6 and having the collector side of Q6 in the positive direction is V6. It is defined as

Further, three-phase currents I1 and I flowing through the load
The direction in which 2 and I3 flow into the load is defined as the positive direction. In addition, ON / OF of the main switching elements Q1 to Q6
Regarding the definition of F, the main switching element Q1 on the upper side (plus side) of the U phase of the main switching circuit 2A is ON and the main switching element Q2 on the lower side (minus side) is OF.
The state of F is "1", the main switching element Q1 on the upper side of the U phase is OFF and the main switching element Q2 on the lower side is ON.
Is represented as "0", similarly, the main switching element Q3 on the upper stage side of the V phase is ON and the main switching element Q on the lower stage side is ON.
When 4 is OFF, the main switching element Q on the upper side of the V phase is "1", and the main switching element Q on the lower side of V phase is OFF.
The state in which 4 is ON is set to "0". In the W phase, the state where the main switching element Q5 on the upper side is ON and the main switching element Q6 on the lower side is OFF is "1", and the main switching element Q5 on the upper side of the W phase is OFF and the main switching element Q6 on the lower side is The ON state is set to "0". In addition, the auxiliary circuit 2B
In the state in which the auxiliary switching element Q7 on the upper side of the U'phase is ON and the auxiliary switching element Q8 on the lower side is OFF
1 ", a state in which the auxiliary switching element Q8 on the lower side of the U'phase is ON and the auxiliary switching element Q7 on the upper side is OFF is represented as" 0 ". Similarly, the auxiliary switching element Q9 on the upper side is ON in the V'phase. The state in which the lower side auxiliary switching element Q10 is OFF is "1", and the state in which the lower side auxiliary switching element Q10 of the V'phase is ON and the upper side auxiliary switching element Q11 is OFF is "0".
Also in the W ′ phase, the auxiliary switching element Q11 on the upper side is ON and the auxiliary switching element Q12 on the lower side is OFF state is “1”, and the auxiliary switching element Q1 on the lower side of the W ′ phase is
2 is ON and the auxiliary switching element Q11 on the upper side is OF
The state of F is set to "0". Therefore, for example, the control CPU 5
Output three-phase control signal (Us, Vs, Ws) =
(1, 0 1, 0): When expressed as an output voltage vector V1, the main switching element Q1 is ON, the main switching element Q2 is OFF, the main switching element Q3 is OFF, the main switching element Q4 is ON, and the main switching element Q5.
Is OFF and the main switching element Q6 is ON. Further, the switching control signal for each switching element of the inverter circuit output from the drive signal generation means 6 cuts off the logical value "0" and sets "1" to conduction.

Further, the operation shown in FIG. 9 is a three-phase control signal (Us, Vs, W) as an example for explaining the control mode.
s) is (1, 0, 0): output voltage vector V1->
(0, 0, 1): Output voltage vector V4-> (1, 1,
0): A case will be described in which control is performed using space vector control in which the output voltage vector V3 and the output voltage vector are sequentially switched. The space vector control is, as shown in FIG. 14, π / 3 [rad] according to the rotation angle θ (rotation position) of the motor.
The output voltage vector is assigned to six regions each having a different angle, and the switching control pattern is switched and controlled.

The operation of the circuit is the same for controls other than the above. Next, the operation of the inverter control device will be described with reference to FIGS. 8 to 13 based on the definitions of the voltage and current of each portion and ON / OFF of each switching element defined above.

First, at time t1, (U, V, W) =
Since the steady state is (1, 0, 0), (a) mode 1
As shown in FIG.
The electric current that has flowed toward the U-phase terminal of the motor 1 via the flow returns to the DC power supply 3 from the V-phase terminal and the W-phase terminal of the motor 1 through the main switching elements Q4 and Q6, respectively. In the steady state of mode 1, the auxiliary switching elements Q7, Q9, Q12 of the positive side switching elements of the auxiliary circuit 2B are also included.
Is ON and the auxiliary switching elements Q8, Q10, Q11 of the L-side switching element are OFF, but no energy is stored in the resonance inductance Lr, so that no current flows in the resonance inductance Lr.

This (Us, Vs, Ws) = (1, 0,
0): From the steady state of the output voltage vector V1, the control CP
When U5 changes the three-phase control signal to the state of (Us, Vs, Ws) = (0, 0, 1): output voltage vector V4, as shown in (b) mode 2, the drive signal generation means 6
Are switching control signals S8 and S1 for the auxiliary switching elements Q8 and Q11 of the auxiliary switching circuit 2B.
The logical value of 1 is switched from "0" to "1" and the auxiliary switching elements Q8 and Q11 are turned on. At this time, part of the current flowing from the main switching element Q1 to the U-phase terminal of the motor 1 flows through the resonance inductance Lr, returns to the DC power supply 3 via the main switching elements Q4 and Q6, and the resonance inductance Lr receives the current ILr. The energy with the initial current is stored. The auxiliary switching elements Q8 and Q11 are turned on, and the inductance current I4 starts to flow. At time t2, the inductance current I4 is the maximum absolute value of the load current (in the example of FIG.
When it becomes larger than 1), the output I of the resonance current arrival judging means 7 changes from the logical value "0" to "1", and in response to this, the drive signal generating means 6 shows the mode 3 as shown in (c) mode 3. The main switching element Q of the main switching circuit 2A
The switching control signals S1 and S6 for 1 and Q6 are switched from the logical value "1" to "0" to turn off the main switching elements Q1 and Q6. At this time, in the main switching elements Q1 and Q6, the main switching elements Q1 and Q6 are caused by the time constants of the buffer capacitors C1 and C6.
The voltage V1 between the collector terminal and the emitter terminal of V6, and V
6 cannot rise rapidly, so the main switching element Q
ZVS in 1 and Q6 is realized.

When the main switching elements Q1 and Q6 are turned off, the buffer capacitors C1 and C6 are charged and the voltage V2 across the buffer capacitors C2 and C5, to which a voltage close to the power supply voltage VB has been applied, is applied. , V5
When the buffer capacitors C1 and C6 are connected, the discharge of the buffer capacitors C2 and C5 starts, and the voltage drops accordingly.

The charging currents of the buffer capacitors C1 and C6 and the discharging currents of C2 and C5 flow as resonance currents through the resonance inductance Lr and become a resonance mode in which they circulate in the circuit. Further, if this resonance mode is continued, the resonance current further flows due to the energy accumulated in the resonance inductance Lr, and when the voltages V2 and V5 across the buffer capacitors C2 and C5 become almost "zero", the resonance occurs. The energy stored in the inductor Lr will flow through the commutation diodes D2 and D5.

Next, at time t3, the voltage sensor Vs2 for measuring the voltage between the collector terminal and the emitter terminal of the main switching elements Q2 and Q5 of the main switching circuit 2A.
And Vs5 detect that the voltage between the collector terminal and the emitter terminal of the main switching elements Q2 and Q5 has become "zero", and the outputs Z2 and Z5 of the zero voltage detecting means 8 change from the logical value "0" respectively. Switch the output to "1". In response to this, the drive signal generation means 6 causes the main switching circuit 2
The switching control signals S2 and S5 for the main switching elements Q2 and Q5 of A are switched from the logical value "0" to "1" to turn on the main switching elements Q2 and Q5.
(Us, Vs, Ws) = (0, 0, 1): The output voltage vector V4 is shifted to the regeneration mode shown in (d) mode 4.

At this time, in the main switching elements Q2 and Q5, the voltages V2 and V5 between the collector terminal and the emitter terminal of the main switching elements Q2 and Q5 are "zero", and the currents are respectively supplied to the commutation diodes D2 and D5. Since it is flowing, ZVS and ZCS in the main switching elements Q2 and Q5 are realized.

In the regenerative mode of the mode 4, the regenerative energy of the motor 1 and the energy stored in the resonance inductance Lr are used to transfer the positive side of the DC power source 3 from the W-phase terminal of the motor 1 via the main switching element Q5. To the negative side of the DC power supply 3 from the V-phase terminal of the motor 1 through the main switching element Q4, the regenerative current flowing through the main switching element Q2 to the U-phase terminal of the motor 1, and Is an auxiliary switching element Q
8, a current flowing through the resonance inductance Lr and the auxiliary switching element Q11 is generated. However, since the power supply voltage of the DC power supply 3 is applied to the resonance inductance Lr as a reverse voltage in the direction of decreasing the current ILr, the current Ir is reduced.
Lr gradually decreases to zero. When the current ILr becomes zero, the protection diodes D8 and D11 prevent the current due to the power supply voltage of the DC power supply 3 from flowing to the auxiliary switching elements Q8 and Q11 on the emitter side, and shift to the steady mode (e) mode 5. . Next, at time t4, (Us, Vs, Ws) = (0,
0, 1): When the control CPU 5 changes the three-phase control signal from the steady state of the output voltage vector V4 to the state of (Us, Vs, Ws) = (1, 1, 0): output voltage vector V3, (F) As shown in mode 6, the drive signal generating means 6 causes the switching control signal S for the auxiliary switching elements Q7, Q9 and Q12 of the auxiliary switching circuit 2B.
7 and S9 and S12 are switched from the logical value "0" to "1", and the auxiliary switching elements Q7, Q9 and Q12 are turned on.

Auxiliary switching elements Q7, Q9 and Q12
Is turned on to cause the inductance current I4 to flow out, and at time t5, the inductance current I4 becomes larger than the maximum value of the absolute value of the load current (I1 in the example of FIG. 9) (g). The output I of the current arrival determination means 7 is switched from the logical value "0" to "1", and accordingly, the drive signal generation means 6 switches the main switching elements Q2, Q4 and Q5 of the main switching circuit 2A. The control signals S2, S4 and S5 are switched from the logical value "1" to "0", the main switching elements Q2, Q4 and Q5 are turned off (h) and the mode 8 is entered. At this time, the main switching elements Q2, Q4 and Q
5, the main switching elements Q2, Q4 and Q5 are set by the time constants of the buffer capacitors C2, C4 and C5.
Since the voltages V2, V4, and V5 between the collector terminal and the emitter terminal of the above cannot rapidly increase, ZVS in the main switching elements Q2, Q4, and Q5 is realized.

The main switching elements Q2, Q4 and Q
When 5 is turned off, buffer capacitors C2 and C
The voltages V1 and V3 and V6 of the buffer capacitors C1, C3 and C6, to which a voltage close to the power supply voltage VB has been applied until now, are charged by the buffer capacitors C2 and C5.
4 and C5 are connected so that a buffer capacitor C1
And C3 and C6 discharge begins and therefore drops. The charging current of these buffer capacitors C2, C4, C5 and C1
The discharge currents of C3 and C6 flow in the resonance inductance Lr as resonance currents and become a resonance mode in which they circulate in the circuit.

Further, when this resonance mode is continued, the resonance current further flows due to the energy accumulated in the resonance inductance Lr, and the buffer capacitors C1, C3 and C6.
When the voltages V1, V3, and V6 across both ends of the diode become "zero", the energy stored in the resonance inductance Lr is, as shown in (i) mode 9, the commutation diode D1.
And through D3 and D6.

Next, at time t6, the voltage sensors Vs1, Vs3 and Vs6 measuring the voltage between the collector terminal and the emitter terminal of the main switching elements Q1, Q3 and Q6 of the main switching circuit 2A become the main switching elements Q1 and Q3. And the voltage between the collector and emitter terminals of Q6 is "
It is detected that the output has become "zero", and the outputs Z1, Z3 and Z6 of the zero voltage detecting means 8 are changed from logical values "0" to "0", respectively.
The output is switched to 1 ". In response to this, the drive signal generating means 6 sets the switching control signals S1, S3 and S6 for the main switching elements Q1, Q3 and Q6 of the main switching circuit 2A to the logical value" 1 ", Turn on the main switching elements Q1, Q3, and Q6 to turn on (Us, Vs, W
s) = (1,1,0): (j) of the output voltage vector V3
Transition to the steady state shown in mode 10.

At this time, in the main switching elements Q1, Q3 and Q6, the voltages V1, V3 and V6 between the collector terminal and the emitter terminal of the main switching elements Q1, Q3 and Q6.
Is "zero" and the energy stored in the inductance is flowing in the commutation diodes D1, D3 and D6 as currents respectively, so that the main switching element Q
No current is flowing in 1 and Q3 and Q6, so that ZVS and ZCS in the main switching elements Q1, Q3 and Q6 are realized.

From the time t1 to the time t6, (U
s, Vs, Ws) (1, 0, 0): output voltage vector V1-> (0, 0, 1): output voltage vector V4->
(1, 1, 0): The operation of the inverter circuit in the case of controlling with the output voltage vector V3 has been described. However, when the space vector PWM control is performed on the inverter circuit, the operation of the inverter circuit at the transition between other control vectors is also explained. , (Us, Vs, Ws) is (1, 0, 0)-> (0,
This is the same as the case of controlling 0, 1)-> (1, 1, 0).

[0032]

As described above, in the soft switching inverter device, when the main switching element is turned on and turned off, the resonance inductance in the auxiliary circuit and the main switching element are connected in parallel. By performing resonance with the resonance capacitor, the slope of the change in the voltage between the terminals of the main switching element is moderated to establish soft switching.

However, when the main switching element is turned off from the state in which the current is conducted to the main switching element, the load current is conducted to the main switching element until immediately before the turn-off, so that the auxiliary current is further assisted. It is possible to charge and discharge the capacitor between the terminals of the main switching element without passing a resonance current through the circuit.

When the auxiliary circuit is turned on while the current is flowing through the main switching element, the auxiliary circuit is connected in parallel with the load. Then, the amount of increase in current due to the conduction of the auxiliary circuit is superimposed on the load current flowing in the main switching element, and the amount of increase in current increases the conduction loss of the main switching element.

The present invention has been made to solve the above problems, and provides an inverter device with less loss and higher efficiency than conventional ones.

[0036]

According to a first aspect of the present invention, a DC current output from a power supply (power supply VB in the embodiment) is converted into a three-phase AC current and supplied to a three-phase motor (motor 1 in the embodiment). An inverter circuit (main circuit 2A in the embodiment),
A resonance type inverter device having a resonance circuit (auxiliary circuit 2B in the embodiment) connected to the output terminal of the inverter circuit and a control circuit (control circuit 3 in the embodiment) for controlling the resonance circuit and the inverter circuit. Therefore, the inverter circuit includes a main switching element (for example, main switching element Q1 in the embodiment) connected to the positive terminal of the power source and a main switching element (in the embodiment, main switching element Q1) connected to the negative terminal of the power source. For example, a main switching element Q2) is connected in series, and a diode (in the embodiment, for example, diodes D1 and D2) is connected in parallel with each of these two main switching elements.
The main circuit for each phase (in the embodiment, for example, the main circuit 2U for each phase) connected to each other is connected in parallel to the three-phase main circuit connected in parallel and the main switching element in each main circuit for each phase. Capacitors (capacitors C1 to C6 in the embodiment),
A main connection point where two main switching elements in each phase-specific main circuit are connected to each other (in the embodiment, main connection points PSU, PS
V, PSW) and a load current (load currents I1, I2, I3 in the embodiment) flowing between the motor and the motor (load current sensor Is1, in the embodiment).
Is2, Is3) and the inter-terminal voltage of the main switching element in each phase-specific main circuit (inter-terminal voltages V1 to V in the embodiment).
6) for detecting inter-terminal voltage sensors (in the embodiment, inter-terminal voltage sensors Vs1 to Vs6), the resonance circuit has two auxiliary switching elements (in the embodiment, that allow current to pass only in one direction). , For example, the auxiliary switching element blocks B7 and B8) are connected in series (in the embodiment, for example, the auxiliary circuit 3U for each phase).
Is connected in parallel, and two auxiliary switching elements in each auxiliary circuit for each phase are connected to each other (auxiliary connection points PHU, PHV, PHW in the embodiment) and the main of the inverter circuit. A three-phase auxiliary circuit connected to the connection point, a resonance inductance (inductance Lr in the embodiment) connected between terminals on the opposite side of the auxiliary connection point in the phase-dependent auxiliary circuit, and a current flowing through this inductance. A resonance current sensor (resonance current sensor Is4 in the embodiment) that detects a resonance current (resonance current I4 in the embodiment), and the control circuit has a zero terminal voltage detected by each terminal voltage sensor. Zero voltage detection means for detecting whether or not, and outputs zero voltage detection signals (zero voltage detection signals z1 to z6 in the embodiment) corresponding to the voltage between terminals when the voltage is zero (implementation). In the state, it is determined whether or not the resonance current detected by the zero voltage detection means 8) and the resonance current sensor is larger than the load current detected by the load current sensor. I) which outputs the resonance current arrival determination means (resonance current arrival determination means 7 in the embodiment), and when the resonance current arrival determination means outputs the arrival determination signal, turns off the main switching element that is brought into a non-conducting state next. A main switching element that generates a main drive signal (main drive signals S1 to S6 in the embodiment) and that is brought into a conductive state next time when the zero voltage detection unit outputs a zero voltage detection signal corresponding to a voltage between terminals. To generate a main drive signal for turning on the auxiliary switching element at a predetermined switching timing (in the embodiment, the auxiliary drive signal is generated). S7 to S12) to generate an auxiliary drive signal for turning off the conductive auxiliary switching element after a predetermined ON duration has elapsed from the default switching timing (drive signal generating means 6 in the embodiment). ) And a current conducting device discriminating means (in the embodiment, current conducting device discriminating means 16U, 16V, 16W) for discriminating which of the main switching element or the diode the current is flowing in the main circuit for each phase in the inverter circuit. ) And
The drive signal generating means, when the current conducting device determining means determines that a current is flowing through the main switching element, assists turning on the corresponding auxiliary switching element in the resonant circuit when the main switching element is turned off. Resonance operation prohibiting means for prohibiting generation of a drive signal (resonance operation prohibiting means 1 in the embodiment
7) is provided.

According to the above structure, the current conducting device determining means determines which of the main switching element or the diode the current is flowing in the main circuit for each phase in the inverter circuit, and the resonance operation inhibiting means is When the current conducting device determination means determines that the current is flowing through the main switching element, it is prohibited to generate the auxiliary drive signal for turning on the corresponding auxiliary switching element in the resonance circuit when the main switching element is turned off.

Therefore, it becomes possible to perform the soft switching control without supplying an unnecessary resonance current. This allows
The loss in the main switching element, the auxiliary switching element, and the resonance inductance can be reduced, and the efficiency is improved.

In the collective resonance snubber inverter, two-phase switching is always required for resonance operation.
Since switching with only one phase is impossible, π / 3 depending on the switching control pattern of the inverter circuit.
Six output voltage vectors V1 (1,0,0), V2 (0,1,0), V represented by three-phase control signals according to the switching control pattern, the angles of which differ by [rad]
3 (1,1,0), V4 (0,0,1), V5 (1,
0, 1), V6 (0, 1, 1) is switched and output, in the output vector, the output voltage vector before or after switching and the π [ra
d] Outputting reverse voltage vectors having different angles for a predetermined time,
After that, it is necessary to output the output voltage vector after switching, and when switching the output voltage vector, there was a constraint that it could not switch to the adjacent output voltage vector. Since it is possible to prohibit, it is possible to perform switching in only one phase without outputting the reverse voltage vector, it is possible to switch to adjacent output voltage vectors, and the degree of freedom of control is improved.

According to a second aspect of the invention, the current conducting device discriminating means of the first invention discriminates the current conducting direction discriminating means (in the embodiment, the current conducting direction discriminating means) for discriminating the direction in which the load current detected by the load current sensor flows. 18), the direction in which the load current determined by the current conduction direction determination means flows, and the main drive signal generated by the drive signal generation means,
In the main circuit for each phase in the inverter circuit, a logic operation means (a logic operation means 19 in the embodiment) for determining which of the main switching element and the diode the current is flowing is provided.

According to the above construction, the current conducting direction discriminating means discriminates the direction in which the load current detected by the load current sensor flows, and the logical operation means determines the load current flowing direction discriminated by the current conducting direction discriminating means. Based on the main drive signal generated by the drive signal generating means, it is determined which of the main switching element and the diode the current is flowing in the main circuit for each phase in the inverter circuit.

[0042]

1 is a circuit diagram showing the configuration of an inverter device according to an embodiment of the present invention. The inverter device according to the present embodiment includes a main circuit 2A that converts a DC current output from the power supply VB into a three-phase AC current and supplies the three-phase AC current to the motor 1, an auxiliary circuit 2B connected to an output terminal of the main circuit 2A, and an auxiliary circuit. The control circuit 3 controls the circuit 2B and the main circuit 2A. A smoothing capacitor CB is connected between the positive terminal and the negative terminal of the power source VB.

The main circuit 2A comprises a three-phase main circuit, six capacitors C1 to C6, and three phase load current sensors Is1 to Is1.
It has Is3 and six inter-terminal voltage sensors Vs1 to Vs6.

The three-phase main circuit is composed of three phase-specific main circuits 2U, 2V and 2W connected in parallel.

The phase-dependent main circuit 2U is connected in parallel with the main switching element Q1 connected to the positive terminal of the power source VB, the main switching element Q2 connected to the negative terminal of the power source VB, and the main switching element Q1. Diode D
1 and a diode D2 connected in parallel with the main switching element Q2. Main switching element Q
Specifically, 1 and Q2 are IGBTs (Insulated Ga).
te Bipolar Transistor), that is, an insulated gate bipolar transistor. That is, the collector of the main switching element Q1 is connected to the plus terminal of the power source VB, and the emitter of the main switching element Q2 is connected to the minus terminal of the power source VB. Main switching element Q
1 and the main switching element Q2 are connected in series at the main connection point PSU. That is, the main switching element Q
The emitter of 1 and the collector of the main switching element Q2 are connected at the main connection point PSU. The anode of the diode D1 is connected to the emitter of the main switching element Q1 and the cathode of the diode D1 is connected to the collector of the main switching element Q1.

The phase-dependent main circuit 2V is connected in parallel with the main switching element Q3 connected to the positive terminal of the power source VB, the main switching element Q4 connected to the negative terminal of the power source VB, and the main switching element Q3. Diode D
3 and a diode D4 connected in parallel with the main switching element Q4. Main switching element Q
Specifically, 3 and Q4 are IGBTs (Insulated Ga).
te Bipolar Transistor), that is, an insulated gate bipolar transistor. In addition, the main switching elements Q3 and Q4 in the main circuit 2V for each phase, the diode D3,
The connection relationship with D4 is the same as that of the phase-specific main circuit 2U, and the description thereof is omitted.

The phase-dependent main circuit 2W is connected in parallel with the main switching element Q5 connected to the positive terminal of the power source VB, the main switching element Q6 connected to the negative terminal of the power source VB, and the main switching element Q5. Diode D
5 and a diode D6 connected in parallel with the main switching element Q6. Main switching element Q
Specifically, 5 and Q6 are IGBTs (Insulated Ga).
te Bipolar Transistor), that is, an insulated gate bipolar transistor. In addition, the main switching elements Q5 and Q6 in the main circuit 2W for each phase, the diode D5,
The connection relationship with D6 is the same as that of the phase-specific main circuit 2U, and thus the description thereof is omitted.

The six capacitors C1 to C6 are connected in parallel with the main switching elements in each phase-specific main circuit 2U, 2V, 2W.

That is, the capacitor C1 is connected in parallel with the main switching element Q1 in the phase-specific main circuit 2U, and the capacitor C2 is connected in parallel with the main switching element Q2 in the phase-specific main circuit 2U. Specifically, the capacitor C1 is connected between the collector and the emitter of the main switching element Q1. Further, the capacitor C2 is connected between the collector and the emitter of the main switching element Q2.

The connection relationship between the main switching elements Q3 and Q4 in the phase-specific main circuit 2V and the capacitors C3 and C4 is the same as that in the phase-specific main circuit 2U, and the description thereof will be omitted.
Further, the main switching elements Q5, Q in the main circuit 2W for each phase
6, and the connection relationship between the capacitors C5 and C6 is the same as that of the phase-specific main circuit 2U, and therefore the description thereof is omitted.

Load current sensors Is1 to Is3 for three phases
Are main switching elements Q1, Q3, Q5 and main switching elements Q2, Q in the main circuits 2U, 2V, 2W for each phase.
Main connection points PSU, PSV, PS to which 4 and Q6 are connected
Load currents I1, I2, I flowing between W and the motor 1
3 is detected and a load current signal is output. That is, the load current sensors Is1 to Is3 are connected to the main circuits 2U and 2 for each phase.
It is connected between the motor 1 and main connection points PSU, PSV, PSW to which the main switching elements Q1, Q3, Q5 in V, 2W and the main switching elements Q2, Q4, Q6 are connected. The motor 1 is a three-phase brushless motor.

Six inter-terminal voltage sensors Vs1 to Vs6
Detects the voltage across the terminals of the main switching elements Q1 to Q6 in the main circuits 2U, 2V, 2W for each phase. That is, the inter-terminal voltage sensors Vs1 to Vs6 are the main circuits for each phase 2U,
It is connected between the collector and emitter of the main switching elements Q1 to Q6 in 2V and 2W.

The auxiliary circuit 2B has a three-phase auxiliary circuit, a resonance inductance Lr, and a resonance current sensor Is4.

The three-phase auxiliary circuit is composed of three phase-dependent auxiliary circuits 3U, 3V and 3W connected in parallel.

The phase-dependent auxiliary circuit 3U is composed of an auxiliary switching element block B7 that allows a current to flow from the auxiliary circuit 3 and an auxiliary switching element block B8 that allows a current to flow into the auxiliary circuit 3. The auxiliary switching element block B7 and the auxiliary switching element block B8 are connected in series at the auxiliary connection point PHU.

The auxiliary switching element block B7 is composed of an auxiliary switching element Q7 and a diode D7. Diode D7 and auxiliary switching element Q
7 are connected in series. Auxiliary switching element Q
7 is an IGBT (Insulated Gate Bipolar)
Transistor), that is, an insulated gate bipolar transistor. That is, the cathode of the diode D7 and the collector of the auxiliary switching element Q7 are connected. Therefore, this auxiliary switching element block B
7 passes current only in a single direction.

The auxiliary switching element block B8 is composed of an auxiliary switching element Q8 and a diode D8. Auxiliary switching element Q8 and diode D
8 is connected in series. Auxiliary switching element Q
8 is an IGBT (Insulated Gate Bipolar)
Transistor), that is, an insulated gate bipolar transistor. That is, the auxiliary switching element Q8
Is connected to the anode of the diode D8. Therefore, this auxiliary switching element block B8
Also passes current in only one direction.

Auxiliary switching element block B
The emitter of the auxiliary switching element Q7 in 7 and the collector of the auxiliary switching element Q8 in the auxiliary switching element block B8 are connected at the auxiliary connection point PHU. The auxiliary connection point PHU is connected to the main connection point PSU in the phase-dependent main circuit 2U in the main circuit 2A.

The phase-dependent auxiliary circuit 3V includes an auxiliary switching element block B9 and an auxiliary switching element block B1.
It is composed of 0 and. The connection relationship between the auxiliary switching element block B9 and the auxiliary switching element block B10 in the phase-specific auxiliary circuit 3V and the internal configuration are the same as those of the phase-specific auxiliary circuit 3U, and therefore description thereof will be omitted.

The auxiliary circuit 3W for each phase includes an auxiliary switching element block B11 and an auxiliary switching element block B.
It is composed of 12 and. The connection relationship between the auxiliary switching element block B11 and the auxiliary switching element block B12 in the phase-specific auxiliary circuit 3W and the internal configuration are the same as those of the phase-specific auxiliary circuit 3U, and thus the description thereof will be omitted.

The resonance inductance Lr is provided between the upper ends of the auxiliary switching element blocks B7, B9, B11 and the lower ends of the auxiliary switching element blocks B8, B10, B12 in the auxiliary circuits 3U, 3V, 3W for each phase. It is connected. That is, the inductance Lr depends on the anodes of the diodes D7, D9, D11 in the auxiliary switching element blocks B7, B9, B11 and the diode D in the auxiliary switching element blocks B8, B10, B12.
It is connected between the cathodes of 8, D10 and D12.

The resonance current sensor Is4 detects the resonance current flowing through the inductance Lr. Therefore, the resonance current sensor Is4 is connected in series with the inductance Lr.

The control circuit 3 includes a zero voltage detection means 8, a resonance current arrival determination means 7, a control CPU 5, a drive signal generation means 6, a drive circuit 9, and current conduction device determination means 16U, 16V, 16W. Have.

The zero voltage detecting means 8 detects whether the inter-terminal voltages V1 to V6 detected by the inter-terminal voltage sensors Vs1 to Vs6 in the main circuit 2A are zero. The zero voltage detection signals z1 to z6 corresponding to the inter-terminal voltages V1 to V6 are output.

The resonance current arrival determining means 7 is the auxiliary circuit 2B.
Resonance current I4 detected by the resonance current sensor Is4 in
Are load current sensors Is1 and Is in the main circuit 2A.
2, it is determined whether or not Is3 is larger than the detected load currents I1, I2, I3, and if larger, the arrival determination signal I is output.

The control CPU 5 outputs an output command signal Os indicating a command value (torque command, speed command, etc.) to the motor from an operation unit (not shown), and a rotation sensor 4 for detecting the rotational position and speed of the motor 1. Rotation position / speed signal Ps
The PWM signals Us, Vs, and Ws are output based on

The drive signal generating means 6 outputs main drive signals S1 to S6 and auxiliary drive signals S7 to S12 based on the PWM signals Us, Vs and Ws output from the control CPU 5. Main drive signals S1 to S6 and auxiliary drive signals S7 to S
Reference numeral 12 denotes a drive circuit 9, which is a main drive signal Sd1 to Sd6.
Is converted into auxiliary drive signals Sd7 to Sd12.

Main drive signals Sd1, Sd2, Sd3, Sd
4, Sd5 and Sd6 are main switching elements Q1, Q2, Q3, Q4, Q5 and Q in the main circuit 2A, respectively.
It is inputted to the gate of 6 and switches (turns on or off) these main switching elements.

Auxiliary drive signals Sd7, Sd8, Sd9, S
d10, Sd11, and Sd12 are auxiliary circuits 2 respectively.
Auxiliary switching elements Q7, Q8, Q9, Q in B
Input to the gates of 10, Q11 and Q12 to switch (turn on or turn off) these auxiliary switching elements.

When the resonance current arrival determination means 7 outputs the arrival determination signal I, the drive signal generation means 6 turns off the main switching element to be turned off next among the main switching elements in the conductive state. Main drive signal S1
~ S6 is generated.

Further, the drive signal generating means 6 includes one of the main switching elements in the non-conducting state when the zero voltage detecting means 8 outputs the zero voltage detecting signals z1 to z6 corresponding to the inter-terminal voltages V1 to V6. Then, main drive signals S1 to S6 for turning on the main switching element to be turned on next are generated.

The drive signal generating means 6 is a control CPU.
The auxiliary drive signals S7 to S12 for turning on the corresponding auxiliary switching elements Q7 to Q12 in the auxiliary circuit 2A are generated in synchronization with the predetermined switching timings of the PWM signals Us, Vs, and Ws output from the circuit 5.

The drive signal generating means 9 is a control CPU.
5 is an auxiliary drive signal for turning off the corresponding auxiliary switching elements Q7 to Q12 in the auxiliary circuit 3 after a predetermined ON duration has elapsed from the predetermined switching timing of the PWM signals Us, Vs, and Ws. S7 to S12 are generated.

Current conduction device discriminating means 16U, 16
V and 16W are main circuits 2U for each phase in the main circuit 2A,
It is determined which of the main switching element and the diode the current is flowing within 2V and 2W.

That is, the current conducting device discrimination means 16
The U determines which of the main switching elements Q1 and Q2 or the diodes D1 and D2 the current is flowing in the phase-dependent main circuit 2U in the main circuit 2A. The current conducting device determination unit 16U inputs the main drive signals S1 and S2 output by the drive signal generation unit 6 and the load current signal output by the load current sensor Is1 in the main circuit 2A, and indicates the determination result. The discrimination signal HU is output.
The output current conduction device determination signal HU is input to the drive signal generation means 6.

Further, the current conducting device discrimination means 16V
Determines which of the main switching elements Q3, Q4 or the diodes D3, D4 is flowing current in the phase-dependent main circuit 2V of the main circuit 2A. The current conducting device determination means 16V inputs the main drive signals S3 and S4 output from the drive signal generation means 6 and the load current signal output from the load current sensor Is2 in the main circuit 2A, and indicates the determination result. The discrimination signal HV is output. The output current conduction device determination signal HV is input to the drive signal generation means 6.

Further, the current conducting device discrimination means 16W
Determines which of the main switching elements Q5, Q6 or the diodes D5, D6 is in the main circuit 2W for each phase in the main circuit 2A. The current conducting device determination means 16W inputs the main drive signals S5 and S6 output by the drive signal generation means 6 and the load current signal output by the load current sensor Is3 in the main circuit 2A, and indicates the determination result. The discrimination signal HW is output. The output current conduction device determination signal HW is input to the drive signal generation means 6.

The drive signal generating means 6 has a resonance operation inhibiting means 17 built therein. When the current conducting device determining means 16U, 16V, 16W determine that the current is flowing through the main switching element, the resonance operation prohibiting means 17 turns off the main switching element, and then the corresponding auxiliary switching element in the auxiliary circuit 2B. It is prohibited to generate an auxiliary drive signal that turns on the.

That is, in the resonance operation inhibiting means 17, the current conducting device determining means 16U is the main switching element Q.
When it is determined that a current is flowing through the first and second switching elements Q1 and Q2, the auxiliary circuit 2 is turned off when the main switching elements Q1 and Q2 are turned off.
A corresponding auxiliary switching element Q in B
It is prohibited to generate auxiliary drive signals S7 and S8 for turning on Q7 and Q8.

In the resonance operation prohibiting means 17, the current conducting device discriminating means 16V is the main switching elements Q3, Q.
When it is determined that a current is flowing through the switch 4, the generation of the auxiliary drive signals S9 and S10 for turning on the corresponding auxiliary switching elements Q9 and Q10 in the auxiliary circuit 2B is prohibited when the main switching elements Q3 and Q4 are turned off. To do.

In the resonance operation prohibiting means 17, the current conducting device discriminating means 16W has the main switching elements Q5 and Q5.
When it is determined that a current is flowing through the switch 6, when the main switching elements Q5 and Q6 are turned off, it is prohibited to generate the auxiliary drive signals S11 and S12 that turn on the corresponding auxiliary switching elements Q11 and Q12 in the auxiliary circuit 2B. To do.

FIG. 2 is a flowchart showing the operation of the inverter device according to this embodiment. In the collective resonance snubber inverter, it is necessary to perform two-phase or three-phase switching simultaneously. When two phases are simultaneously switched, one phase is turned off from the positive side main switching element being turned on, the negative side main switching element is turned on from the off state, and the other phase is turned on.
It is necessary to control the operation of the main switching element such that the main switching element on the minus side is turned off from the on state and the main switching element on the plus side is turned on from the off state. When switching three phases simultaneously, for example, when the positive side main switching element of the first phase is on and the negative side main switching element is off, one of the other two phases (2 The second phase) controls so that the main switching element on the minus side always turns off from the on state, and the main switching element on the plus side turns on from the off state. Must be controlled so that the same operation as the first or second phase is performed.

The flow chart shows only the operation of one phase among the operations in the case of simultaneously switching the two phases. Since the operation of the other phase only switches the plus side main switching element and the minus side main switching element, the description thereof will be omitted.

That is, in the flow chart, as a representative example, in the main circuit 2A, Q1 of the U phase shifts from the ON state to the OFF state, Q2 shifts from the OFF state to the ON state, and Q6 of the W phase The transition from the on state to the off state and the transition of Q5 from the off state to the on state are shown.

The operation will be described below with reference to the flowchart. The symbols A1, G1, etc. in the following description represent steps in the flowchart.

The control CPU 5 controls the drive signal generating means 6 to P
The WM signals Us, Vs, and Ws are sent (A1), the main switching element Q1 on the positive side in the U phase is changed from on to off, the main switching element Q2 on the negative side is changed from off to on, and the W phase is also changed. A command for changing the plus side main switching element Q5 from off to on and the minus side main switching element Q6 from on to off is transmitted to the drive signal generating means 6.

The current conducting device discriminating means detects whether or not a current is flowing through the main switching element (G
1). When current is flowing through the main switching element (Y
es), the process proceeds to step G2.

When no current flows through the main switching element, that is, when current flows through the diode (N
In o), the auxiliary switching element Q8 on the inflow side in the U phase of the auxiliary circuit 2B is turned on (A2). The auxiliary switching element Q11 on the outflow side in the W phase of the auxiliary circuit 2B is also turned on at the same time.

Next, it is detected whether the resonance current arrival determination means 7 has output the arrival determination signal I (A3). The resonance current arrival determination means 7 outputs the arrival determination signal I when the resonance current I4 becomes larger than the maximum absolute value of the load currents I1, I2, and I3. If the arrival determination signal I is not output (No), this step is repeated.

If the arrival determination signal I is output (Yes
s), the drive signal generation means 6 sends the drive signal Sd1 to the plus side main switching element Q1 in the U phase of the main circuit 2A via the drive circuit 9 to turn off the conducting plus side main switching element Q1. Allow (A4). At the same time, the drive signal generation means 6 sends the main drive signal Sd6 to the negative side main switching element Q6 in the W phase of the main circuit 2A via the drive circuit 9, and the conduction side negative side main switching element Q6. Turn off.

Next, the drive signal generation means 6 detects whether or not the zero voltage detection signal z2 is output from the zero voltage detection means 8, that is, whether or not the inter-terminal voltage V2 has become zero (A5). . If it is not zero (No),
Repeat this step.

When it becomes zero (Yes), in the U phase of the main circuit 2A, the negative side main switching element Q2 to be turned on next is turned on (A6). When the inter-terminal voltage V5 becomes zero, the main switching element Q5 on the plus side, which is to be turned on next in the W phase of the main circuit 2A, is turned on.

Next, the drive signal generating means 6 operates the auxiliary circuit 2
It is detected whether or not the on-duration of the inflow side auxiliary switching element Q8 in the U phase of B has ended (A7). If the ON duration has not ended (No), this step is repeated.

When the on-duration time ends (Yes), the auxiliary switching element Q8 on the inflow side in the conductive state in the U phase of the auxiliary circuit 2B is turned off (A8). The auxiliary switching element Q11 on the outflow side, which is in the conductive state in the W phase of the auxiliary circuit 2B, is also turned off at the same time.

In step G1, if current is flowing in the main switching element (Yes), step G
2, the drive signal generation means 6 sends the drive signal Sd1 to the plus side main switching element Q1 in the U phase of the main circuit 2A via the drive circuit 9, and the conduction side plus side main switching element Q1. To turn off. In addition,
At the same time, the drive signal generation means 6 causes the drive circuit 9 to
The main drive signal Sd6 is sent to the minus side main switching element Q6 in the W phase of the main circuit 2A to turn off the minus side main switching element Q6 in the conductive state.

Next, the drive signal generation means 6 detects whether or not the zero voltage detection signal z2 is output from the zero voltage detection means 8, that is, whether or not the inter-terminal voltage V2 has become zero (G3). . If it is not zero (No),
Repeat this step.

When it becomes zero (Yes), the main switching element Q2 on the minus side in the U phase of the main circuit 2A to be turned on next is turned on (G4). When the inter-terminal voltage V5 becomes zero, the main circuit 2 is turned on next.
The main switching element Q5 on the positive side in the W phase of A is turned on.

As described above, in the case where a current flows through the main switching element, the auxiliary circuit 2 is turned off when the main switching elements Q1 and Q6 whose current is conducting are turned off.
Corresponding auxiliary switching elements Q8, Q11 in B
Turn-on is controlled so that it is prohibited.

FIG. 3 is a timing chart showing the operation of the inverter device according to this embodiment. For the sake of simplicity, this timing chart shows the operation of the U-phase and V-phase as a single-phase circuit.

For example, the period from time t0 to t1 is
Since current is flowing in the main switching elements Q1 and Q4, the resonance operation prohibiting means 17 conducts current to the main switching elements Q1 and Q4 based on the current conduction device determination signals HU and HV from the current conduction device determination means 16U and 16V. It is determined that the main switching elements Q1 and Q4
The auxiliary switching elements Q8 and Q9 corresponding to
Then do not turn it on. Therefore, in the conventional method, the auxiliary switching elements Q8 and Q9 are turned on from the time t1 to the time t5, but in the present invention, the resonance current does not flow because the auxiliary switching elements Q8 and Q9 continue to turn off, and an unnecessary current does not flow in the main switching element. Therefore, the current consumed in the conventional method in the auxiliary circuit 2B is reduced. Then, at time t2, the main switching elements Q1 and Q4 are turned off, but at this time, due to the stored energy in the stator winding of the motor due to the inductance component included in the motor 1, the resonance capacitor C1 is generated. , C2, C
Since the resonance operation is performed at 3 and C4, ZVS can be realized without operating the auxiliary circuit 2B. Also, at time t5
Then, before the time t5, the main switching element Q2,
Since no current flows in Q3 and a current flows in the diodes D1, D4, the resonance operation prohibiting means 17 determines the main switching element Q1 based on the current conduction device discrimination signals HU, HV from the current conduction device discrimination means 16U, 16V. , Q4
It is determined that the current is not conducted to the diodes D1 and D4, and the auxiliary switching elements Q7 and Q10 of the auxiliary circuit 2B are turned on to start the initial current accumulation operation by the operation of the auxiliary circuit 2B. From t6 to time t7, resonance operation is performed by the stored energy stored in the inductance Lr of the auxiliary circuit 2B, ZVS of the switching elements Q2 and Q3 is realized, and from time t7 to time t8, the main switching elements Q1 and Q4 are turned on. Regenerative operation is performed and the resonance current decreases and becomes zero. Main switching element Q from time t7 to time t8
Since the turn-on of Q1 and Q4 is the regenerative state of the stored energy of the inductance Lr, the main switching element Q
Since current does not flow in 1 and Q4 and current flows in the diodes D1 and D4, switching at this time is ZVS and ZC.
It becomes S. Then, from the time t9 to the time t10, the resonance operation prohibiting means 17 determines that the current is conducted to the main switching elements Q1 and Q4 at the stage before the time t9, similarly to the time from the time t1 to the time t2. The operation of the circuit 2B is prohibited.

FIG. 4 shows the current conducting device discriminating means 16U.
3 is a circuit diagram showing an internal configuration of FIG. Since the internal configurations of the current conducting device determination means 16V and 16W are the same, the description thereof will be omitted.

The current conducting device discriminating means 16U discriminates which one of the main switching elements Q1 and Q2 or the diodes D1 and D2 in the main circuit 2U for each phase in the main circuit 2A the current is flowing. Therefore, the current conducting device determination means 16U causes the main drive signal S to switch the main switching elements Q1 and Q2 in the phase-dependent main circuit 2U.
1, S2, and the load current signal from the load current sensor Is1 that detects the load current I1 flowing between the main connection point PSU in the phase-dependent main circuit 2U and the motor 1 are input.

The current conducting device discriminating means 16U has a current conducting direction discriminating means 18 and a logical operation means 19.

The current conduction direction judging means 18 judges the direction in which the load current I1 detected by the load current sensor Is1 flows. That is, the current conduction direction determination means 18 inputs the load current signal output from the load current sensor Is1,
The current conduction direction signal I1d is output. The current conduction direction signal I1d becomes “1” when current flows from the main connection point PSU in the phase-specific main circuit 2U to the motor 1, and the current flows from the motor 1 to the main connection point PSU in the phase-specific main circuit 2U. When is flowing, it becomes "0".

The logical operation means 19 determines the main switching element Q1 based on the direction in which the load current I1 flows determined by the current conduction direction determination means 18 and the main drive signals S1 and S2 generated by the drive signal generation means 6. , Q2 or the diodes D1 and D2, the current is determined. That is, the logical operation means 19 inputs the current conduction direction signal I1d output from the current conduction direction determination means 18 and the main drive signals S1 and S2 output from the drive signal generation means 6, and outputs the current conduction device determination signal HU. Output. In addition,
Main drive signals S1 and S2 input to the logical operation means 19
Is "1" when the main switching element is turned on and "0" when the main switching element is turned off.
Shall be Further, the current conducting device discrimination signal HU output from the logical operation means 19 becomes "1" when the current flows through the main switching element Q1 or Q2, and when the current flows through the diode D1 or D2. It becomes "0".

The logical operation means 19 includes exclusive OR gates XOR1 and XOR2 and inverters NOT1 and NOT.
2, NOT3 and AND gates AND1, AND2, A
It has ND3, AND4, and a logical sum gate OR1.

The current conduction direction signal I1d output from the current conduction direction judging means 18 is the exclusive OR gate XOR1,
XOR2, inverter NOT1, AND gate AN
It is input to D1 and AND2. The main drive signals S1 and S2 output from the drive signal generating means 6 are input to exclusive OR gates XOR1 and XOR2, respectively.
The output of the exclusive OR gate XOR1 is the inverter NO.
It is input to T2 and the AND gate AND2. The output of the exclusive OR gate XOR2 is the inverter NOT.
3 and the AND gate AND3. The output of the inverter NOT1 is input to the AND gates AND3 and AND4. The output of the inverter NOT2 is input to the AND gate AND1. The output of the inverter NOT3 is input to the AND gate AND4. The outputs of the AND gates AND1 and AND3 are input to the OR gate OR1. A current conduction device determination signal HU is output from the OR gate OR1.

FIG. 5 shows the current conducting device discriminating means 16U.
3 is a timing chart showing the operation of FIG. The operations of the current conducting device determination means 16V and 16W are also the same, and thus the description thereof is omitted.

The exclusive OR gate XOR1 takes the exclusive OR of the main drive signal S1 and the current conduction direction signal I1d, and the exclusive OR gate XOR2 takes the main drive signal S2 and the current conduction direction signal I1d. Take an exclusive OR. Then, the AND gate AND1 is connected to the exclusive OR gate XO.
A signal obtained by inverting the output of R1 and the current conduction direction signal I1d
And the logical product gate AND3 outputs the output signal of the exclusive OR gate XOR2 and the current conduction direction signal I
The logical product is obtained with the signal obtained by inverting 1d. The OR gate OR1 and the output signal of the AND gate AND1
The logical sum of the output signal of the AND gate AND3 is calculated and the current conduction device determination signal HU is output. With this configuration, the current conducting device determination means 16U
In the main circuit 2A, it is possible to determine which of the main switching elements Q1 and Q2 or the diodes D1 and D2 in the phase-dependent main circuit 2U is flowing current.

In the above embodiment, three load current sensors are provided, but there are two load current sensors, two phases are detected, and the remaining one phase is calculated from the detected values of the two phases. The required configuration may be used. Also, as the motor 1,
A three-phase induction motor may be used.

[0111]

According to the present invention, the current conducting device discriminating means discriminates which one of the main switching element and the diode the current is flowing in the main circuit for each phase in the inverter circuit, and the resonance operation inhibiting means. However, when the current conducting device determination means determines that the current is flowing through the main switching element, it is prohibited to generate the auxiliary drive signal for turning on the corresponding auxiliary switching element in the resonance circuit when the main switching element is turned off. Therefore, the conduction loss in the main switching element, the auxiliary switching element, and the resonance inductance can be reduced, and the efficiency is improved.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of an inverter device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the inverter device according to the embodiment of the present invention.

FIG. 3 is a timing chart showing the operation of the inverter device according to the embodiment of the present invention.

FIG. 4 is a circuit diagram showing an internal configuration of a current conducting device determination means 16U.

FIG. 5 is a timing chart showing the operation of the current conducting device determination means 16U.

FIG. 6 is a circuit diagram showing a configuration of a conventional soft switching inverter, which is a circuit diagram generally showing a configuration of what is called an auxiliary resonance arm link snubber system.

FIG. 7 is a circuit diagram showing a configuration of a conventional soft switching inverter, which is also called an auxiliary resonance AC link type inverter.

FIG. 8 is a circuit diagram showing a configuration of a collective resonance snubber inverter device among conventional inverter devices that perform soft switching.

FIG. 9 is a waveform diagram showing waveforms of respective portions of a conventional collective resonance snubber inverter device.

FIG. 10 is a diagram showing an operation in each mode of the conventional collective resonance snubber inverter device.

FIG. 11 is a diagram showing an operation in each mode of the conventional collective resonance snubber inverter device.

FIG. 12 is a diagram showing an operation in each mode of the conventional collective resonance snubber inverter device.

FIG. 13 is a diagram showing an operation in each mode of the conventional collective resonance snubber inverter device.

FIG. 14 is an explanatory diagram of space vector control.

[Explanation of symbols]

VB power supply CB smoothing capacitor 1 motor Is1 to Is3 load current sensor I1 to I3 load current 4 Rotation sensor Ps rotation position / speed signal 2A Main circuit (inverter circuit) 2U, 2V, 2W Phase-specific main circuit Q1-Q6 Main switching element D1 to D6 diode C1 to C6 capacitors Vs1-Vs6 Terminal voltage sensor Voltage between terminals V1 to V6 PSU, PSV, PSW main connection point 2B Auxiliary circuit (resonance circuit) 3U, 3V, 3W Phase-dependent auxiliary circuit B7 to B12 Auxiliary switching element block Q7 to Q12 Auxiliary switching element D7-D12 diode Lr inductance Is4 resonance current sensor I4 resonance current PHU, PSV, PSW auxiliary connection point 3 control circuit 8 Zero voltage detection means z1-z6 Zero voltage detection signal 7 Resonance current arrival determination means I arrival judgment signal 5 control CPU Os output command signal Us, Vs, Ws PWM signal 6 Drive signal generating means 9 drive circuit S1 to S6, Sd1 to Sd6 main drive signals S7 to S12, Sd7 to Sd12 auxiliary drive signal 16U, 16V, 16W current conduction device discrimination means 17 Resonance operation prohibition means 18 Current conduction direction discrimination means I1d Current conduction direction signal 19 Logical operation means HU, HV, HW Current conduction device discrimination signal XOR1, XOR2 Exclusive OR gate NOT1-NOT3 inverters AND1 to AND4 AND gate OR1 OR gate

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5H007 AA01 AA03 BB06 CA01 CB04                       CB05 CB22 CC05 CC07 CC09                       CC23 DA05 DB12 DC02 DC04                       EA09                 5H560 AA08 BB04 DA17 DB20 DC12                       DC13 EB01 EB07 GG04 RR10                       SS02 TT15 UA06 XA02 XA03                       XB00                 5H576 AA01 BB02 CC02 DD02 DD04                       DD07 EE16 GG02 GG04 HA04                       HB02 JJ03 LL01 LL22 LL24                       LL41

Claims (2)

[Claims] 1. An inverter circuit for converting a direct current output from a power supply into a three-phase alternating current and supplying the three-phase motor, and a resonance circuit connected to an output terminal of the inverter circuit.
A resonance type inverter device having the resonance circuit and a control circuit for controlling the inverter circuit, wherein the inverter circuit is connected to a main switching element connected to a positive terminal of the power supply and a negative terminal of the power supply. Three-phase main circuit in which three main phase-dependent main circuits in which diodes are connected in parallel with each of these two main switching elements are connected in series, and a main circuit in each phase A capacitor connected in parallel with the main switching element in the main circuit, and a main connection point in which two main switching elements in each phase-specific main circuit are connected to each other,
A load current sensor that detects a load current flowing between the motor and a terminal voltage sensor that detects a terminal voltage of a main switching element in each phase-specific main circuit, and the resonance circuit is a single Auxiliary connection in which three auxiliary circuits for each phase in which two auxiliary switching elements that pass current only in the direction are connected in series are connected in parallel, and two auxiliary switching elements in each auxiliary circuit for each phase are connected to each other Points and
A three-phase auxiliary circuit connected to the main connection point of the inverter circuit, a resonance inductance connected between terminals on the opposite side of the auxiliary connection point in the phase-dependent auxiliary circuit, and a resonance flowing through this inductance. And a resonance current sensor for detecting a current, the control circuit detects whether the inter-terminal voltage detected by each inter-terminal voltage sensor is zero, and corresponds to each inter-terminal voltage when it is zero. Zero voltage detection means for outputting a zero voltage detection signal, and whether or not the resonance current detected by the resonance current sensor is greater than the load current detected by the load current sensor, and outputs an arrival determination signal when it is larger. Generating a resonance current arrival determining means and a main drive signal for turning off the main switching element to be turned off next when the resonance current arrival determining means outputs the arrival determination signal. When the zero voltage detection means outputs a zero voltage detection signal corresponding to each terminal voltage, a main drive signal for turning on the main switching element to be turned on next is generated, and the auxiliary switching element is turned on at a predetermined switching timing. Drive signal generating means for generating an auxiliary drive signal for turning on, and for generating an auxiliary drive signal for turning off the auxiliary switching element in a conductive state after a predetermined on-duration has elapsed from a predetermined switching timing, and each of the inverter circuits. And a current conducting device discriminating means for discriminating which current is flowing in the main switching element or the diode in the phase-dependent main circuit, and the drive signal generating means, wherein the current conducting device discriminating means is a main switching element. When it is determined that current is flowing, the turn-on of the main switching element A resonance type inverter device, comprising: a resonance operation prohibiting means for prohibiting generation of an auxiliary drive signal for turning on a corresponding auxiliary switching element in the resonance circuit at the time of turning off. 2. The current conducting device discriminating means includes a current conducting direction discriminating means for discriminating a direction in which the load current detected by the load current sensor flows, and a direction in which the load current discriminating by the current conducting direction discriminating means flows. A logical operation means for determining which of the main switching element or the diode the current is flowing in the main circuit for each phase in the inverter circuit based on the main drive signal generated by the drive signal generating means. The resonant inverter device according to claim 1, which is characterized in that.