JP2010178421A - Power supplying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device capable of driving a load by outputting appropriate power from a power storage unit.
A power supply device (1) has a power storage unit (1b) including a first battery (10) and a second battery (11) capable of outputting two voltages, and switches (SW1-SW3), and the power storage unit (1b) is a motor. 3 terminals. The storage unit 1b controls the pulse width of the first switch SW1 and the first switch SW1 and the pulse width of the third switch SW3 when the output voltage is set to an intermediate voltage between the first voltage and the second voltage. The state is repeated alternately.
[Selection] Figure 1

Description

  The present invention relates to a power supply device that supplies power to a load.

  Some electric vehicles incorporate a vehicle power supply device having a plurality of power storage means (capacitors) that can be electrically connected to a vehicle driving motor (see Patent Document 1).

  This power supply device has a power storage unit capable of outputting at least two voltages, and a current adjustment unit that adjusts a current flowing into and out of the power storage unit, and the power storage unit is connected to a terminal of a load unit via the current adjustment unit Has been configured. The power supply device alternately operates the low voltage output and the high voltage output so that the terminal voltage of the load unit is decreased to a value lower than the high voltage from the state where the output voltage of the power storage unit and the terminal voltage of the load unit are high. Thereby, the power supply device repeatedly switches the output voltage of the power storage unit between the low voltage and the high voltage.

JP 2008-67432 A

  However, in the conventional power supply device, only two voltages, a low voltage and a high voltage, can be supplied to the load unit. Therefore, it cannot be said that the conventional power supply apparatus can supply optimum power to the load.

  Then, this invention is proposed in view of the above-mentioned situation, and it aims at providing the electric power supply apparatus which can output suitable electric power from an electrical storage unit and can drive a load.

  The present invention relates to a power supply apparatus that has an electricity storage unit capable of outputting at least two voltages, and the electricity storage unit is connected to a terminal of a load unit. The power supply device includes: a first voltage output unit that uses the output voltage of the power storage unit as a first voltage; a second voltage output unit that uses the output voltage of the power storage unit as a second voltage that is higher than the first voltage; Voltage switching means for alternately operating the first voltage output means and the second voltage output means when the output voltage of the power storage unit and the terminal voltage of the load section are set to an intermediate voltage between the first voltage and the second voltage. . The power storage unit includes a first power storage unit and a second power storage unit, a first switch, a second switch, and a third switch, and when only the first switch and the second switch are turned on, the power storage unit In contrast, when the first power storage unit and the second power storage unit are connected in parallel, and only the third switch is turned on, the first power storage unit and the second power storage unit are connected in series to the load unit. The first switch, the second switch, and the third switch are provided in parallel with the semiconductor switching element and the semiconductor switching element, and the reverse direction to the current direction when the semiconductor switching element is turned on is forward. Including an anti-parallel diode oriented.

  In order to solve the above-described problem, the voltage switching means in the power supply device according to the present invention provides a first switch and a second switch when the output voltage of the power storage unit is set to an intermediate voltage between the first voltage and the second voltage. The state of controlling the pulse width and the state of controlling the pulse width of the third switch are alternately repeated.

  According to the present invention, the state in which the first switch and the second switch are subjected to pulse width control and the state in which the third switch is subjected to pulse width control are alternately repeated, so that the output voltage of the power storage unit is changed to the first voltage and the second voltage. And any intermediate voltage. Thereby, appropriate electric power can be output from an electrical storage unit, and a load can be driven.

It is a circuit diagram of a power supply device shown as an embodiment of the present invention. It is a circuit diagram containing the circuit part of the electrical storage unit part in the electric power supply apparatus shown as embodiment of this invention. In the electric power supply apparatus shown as embodiment of this invention, it is a circuit diagram when the electrical storage unit part is made into the parallel connection state. In the electric power supply apparatus shown as embodiment of this invention, it is a circuit diagram when the electrical storage unit part is made into the serial connection state. It is a figure which shows the operation mode of what switches the semiconductor switching element of an electrical storage unit part between ON and OFF in the electric power supply apparatus shown as embodiment of this invention. In the electric power supply apparatus shown as embodiment of this invention, it is a figure which shows the operation mode of what carries out PWM control of the semiconductor switching element of an electrical storage unit part. It is a flowchart which shows the operation | movement which switches from a high voltage to a low voltage at the time of regeneration of a motor by the electric power supply apparatus shown as embodiment of this invention. It is a timing chart of a switch state at the time of switching from a high voltage to a low voltage at the time of regeneration of a motor by a power supply device shown as an embodiment of the present invention, a voltage, and a current. It is a flowchart which shows the operation | movement which switches from a low voltage to a high voltage at the time of the power running of a motor by the electric power supply apparatus shown as embodiment of this invention. It is a timing chart of a switch state, a voltage, and an electric current at the time of switching from a low voltage to a high voltage when the motor is powered by the power supply device shown as the embodiment of the present invention. Timing chart of switch state, voltage, and current when an intermediate voltage between a first voltage (low voltage) and a second voltage (high voltage) is generated by a power supply device shown as an embodiment of the present invention during powering of a motor It is.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Configuration of Power Supply Device 1]
The power supply apparatus shown as an embodiment of the present invention has a configuration as shown in FIG. The power supply device 1 is mounted on, for example, an electric vehicle. The power supply device 1 supplies power to the motor 3 and stores power regenerated from the motor 3.

  The motor 3 is capable of power generation and power running, and functions as an electric motor and a generator (power generation means). Inverter 2 includes a smoothing capacitor 4 provided at an input end and a plurality of semiconductor switching elements. The inverter 2 is connected to the motor 3 and serves as a control device for power generation and power running of the motor 3. For example, FIG. 1 shows an example in which the inverter 2 uses a three-phase AC inverter and the motor 3 uses a three-phase AC motor, but the operations described below are not limited to these configurations. . The inverter 2 and the motor 3 constitute a load unit.

  Note that the power supply device 1 in the present embodiment is not provided with a breaker such as a reactor for limiting the current supplied to the smoothing capacitor 4 or a relay for cutting off the power supply line at the input end of the smoothing capacitor 4. . This is because an intermediate voltage can be generated by performing pulse width control (PWM (Pulse Width Modulation)) in the power storage unit 1b at the time of voltage switching between the first voltage and the second voltage and powering as described later. .

  In the inverter 2, a PWM (pulse width modulation signal) signal from the inverter drive circuit 20 is supplied to the semiconductor switching element, and the semiconductor switching element is driven on and off.

  The inverter drive circuit 20 generates a PWM signal according to the motor torque command value from the controller 1a. The PWM signal has a larger pulse width as the motor torque command value is higher.

  The power supply device 1 includes a power storage unit 1b (a chain line portion in FIG. 1) and a controller 1a that controls the operation of the power storage unit 1b. The controller 1a includes, for example, a microcomputer and its peripheral circuits (memory, input / output circuit, etc.). The power storage unit portion 1 b is coupled to the input terminal of the inverter 2. The power storage unit 1b is an energy storage unit that supplies driving power to the motor 3 or absorbs power generated by the motor 3.

The current value supplied to the smoothing capacitor 4 from the power storage unit 1b is detected by the current sensor 30 or is estimated and calculated from a signal from the current sensor 30. The detected current value detected by the current sensor 30 is input to the controller 1a. The voltage V _INV between the input terminals of the inverter 2 is measured by the voltage sensor 40. Output voltage V _BAT of power storage unit portion 1b is measured by voltage sensor 50. These voltage detection values are input to the controller 1a.

  FIG. 2 shows an example of a circuit configuration of the power supply device 1.

  The power storage unit unit 1b includes a first battery 10 and a second battery 11 as power storage units. As the 1st battery 10 and the 2nd battery 11, a secondary battery, a capacitor, etc. are used, for example.

  The power storage unit 1b is connected in series to one end of the inverter 2 and the motor 3 and the first switch SW1 connected in series to the first battery 10, and to the other end of the inverter 2 and the motor 3 and the second battery 11. The second switch SW2 and the third switch SW3 that connects the first battery 10 and the second battery 11 in series to the inverter 2 and the motor 3 are provided. That is, when only the first switch SW1 and the second switch SW2 are turned on, the power storage unit 1b places the first battery 10 and the second battery 11 in parallel connection with the inverter 2 and the motor 3, and When only the 3 switch SW3 is turned on, the first battery 10 and the second battery 11 are connected in series to the inverter 2 and the motor 3.

  The first switch SW1, the second switch SW2, and the third switch SW3 include a semiconductor switching element 13 and an antiparallel diode 14. The antiparallel diode 14 is provided in parallel with the semiconductor switching element 13. The antiparallel diode 14 is provided such that the reverse direction to the current direction when the semiconductor switching element 13 is turned on is the forward direction. The first switch SW1, the second switch SW2, and the third switch SW3 can control energization and interruption for at least one direction of current in accordance with a control command from the controller 1a.

  By switching the first switch SW1 and the second switch SW2 by the controller 1a, the first battery 10 and the second battery 11 are switched between the parallel connection state shown in FIG. 3 and the series connection state shown in FIG. The parallel connection state is formed when the first switch SW1 and the second switch SW2 are turned on and the third switch SW3 is turned off. The series connection state is formed when the first switch SW1 and the second switch SW2 are turned off and the third switch SW3 is turned on.

Each first battery 10, the second battery 11 is the voltage varies depending on the condition, in this description, the same voltage, all for the sake of simplicity, the respective battery voltage and the first voltage V _1. Further, when the first battery 10 and the second battery 11 are in the parallel connection state as shown in FIG. 3, the output voltage V _BAT of the power storage unit portion 1 b becomes the first voltage V ₁ . First battery 10, the output voltage _{V BAT} of the power storage unit portion 1b of the case where the second battery 11 is in series connection state as shown in FIG. 4, the second voltage _{V 2.} Therefore, V ₂ = 2V ₁ is obtained. Here, the power storage unit 1b in the parallel connection state of FIG. 3 serves as a first voltage output means, and the power storage unit portion 1b in the series connection state of FIG. 4 serves as a second voltage output means.

Such energy storage unit portion 1b outputs the output voltage V _BAT of the power storage unit portion 1b when the intermediate voltage between the first voltage and the second voltage, the first voltage and the second voltage alternately. In this case, power storage unit unit 1b, the control of the controller 1a, the output voltage _{V BAT} of the power storage unit portion 1b when the intermediate voltage of the first voltages _{V 1} and the second voltage _{V 2,} and the first switch SW1 The state in which the second switch SW2 is subjected to pulse width control and the state in which the third switch SW3 is subjected to pulse width control are alternately repeated.

  Thereby, the power supply device 1 can set the power supplied to the inverter 2 and the motor 3 to an appropriate value.

[Operation mode of power supply device 1]
The power supply device 1 switches the operation mode as shown in FIGS. 5 and 6. FIG. 5 shows an operation mode in which the first switch SW1, the second switch SW2, and the third switch SW3 are switched between an on state and an off state as an example in which the PWM control of the switch is not performed. FIG. 6 shows an operation mode in which pulse width control (PWM) is performed on the first switch SW1, the second switch SW2, and the third switch SW3.

The operation mode shown in FIG. 5 in which the switch is controlled only by on / off will be described. When the operation mode is the operation stop mode, the first switch SW1, the second switch SW2, and the third switch SW3 are all turned off. In this operation stop mode, when the voltage V _L regenerated by the motor 3 is higher than the second voltage V ₂ (2Vb), an abnormality occurs. The charging voltage at this time is a value dependent on a voltage equal to or higher than the voltage _{VL of the} motor 3.

In the first battery one-side operation mode using only the first battery 10, only the first switch SW1 is turned on. When the voltage V _L regenerated by the motor 3 is a voltage between the first voltage V ₁ and the second voltage V ₂ , the first battery 10 is charged with the voltage. This charging voltage is a value dependent on the voltage V _L regenerated by the motor 3. Further, the motor 3 is in the case of power running at a first voltage lower than the voltages V _1, the discharge of the first battery 10 in the voltage is performed. This discharge voltage is a value dependent on the voltage V _L required by the motor 3.

  In the second battery one-side operation mode using only the second battery 11, only the second switch SW2 is turned on, and the second battery 11 performs the same operation as the first battery one-side operation mode.

In the series operation mode, only the third switch SW3 is turned on. As a result, the first battery 10 and the second battery 11 are connected to the motor 3 in series. In this series operation mode, an abnormality occurs when the voltage V _L regenerated by the motor 3 is higher than the second voltage V ₂ (2Vb). The charging voltage at this time is a value dependent on a voltage equal to or higher than the voltage _{VL of the} motor 3. When the voltage _{VL at} which the motor 3 is powered is a voltage between the first voltage V ₁ and the second voltage V ₂ , the first battery 10 and the second battery 11 are discharged at the second voltage V ₂ . Is done. Voltage V _L by the motor 3 is powering is when a first voltage lower voltage than V ₁ was a discharge of the first battery 10 and the second battery 11 in the first voltage V ₁ is performed. The charging voltage and discharging voltage in this series operation mode are values depending on the voltage V _{L at} which the motor 3 is regenerated or powered.

In the parallel operation mode, the first switch SW1 and the second switch SW2 are turned on. As a result, the first battery 10 and the second battery 11 are connected in parallel to the motor 3. In this parallel operation mode, when the voltage V _L regenerated by the motor 3 is a voltage between the first voltage V ₁ and the second voltage V ₂ , the first battery 10 and the first voltage V ₁ The second battery 11 is charged. Voltage V _L by the motor 3 is powering is when a first voltage lower voltage than V ₁ was a discharge of the first battery 10 and the second battery 11 in the first voltage V ₁ is performed. The charging voltage and discharging voltage in this parallel operation mode are values dependent on the voltage V _{L at} which the motor 3 is regenerated or powered.

  FIG. 5 shows the states of the first switch SW1, the second switch SW2, and the third switch SW3 when the battery is short-circuited as the operation mode. When the first switch SW1 and the second switch SW2 are turned on at the same time, a short circuit of the first battery 10 occurs. If the first switch SW1 and the third switch SW3 are simultaneously turned on, a short circuit of the second battery 11 occurs. When all of the first switch SW1, the second switch SW2, and the third switch SW3 are turned on, a short circuit between the first battery 10 and the second battery 11 occurs.

The operation mode shown in FIG. 6 performs PWM control on the first switch SW1, the second switch SW2, and the third switch SW3. The difference between the operating mode shown in FIG. 5, when the first battery side operation mode, so that the voltage V _L to be regenerated is between the first voltage V ₁ of the second voltage V _2, the first switch SW1 PWM control is performed. Further, when the second battery side operation mode, so that the voltage _{V L} to be regenerated is between the first voltage _{V 1} of the second voltage _{V 2,} the second switch SW2 to PWM control. Furthermore, the series operation mode, so that the required voltage V _L is between the first voltage V ₁ of the second voltage V _2, the intermediate voltage discharge voltage first voltages V ₁ and the second voltage V ₂ The third switch SW3 is PWM-controlled so as to do this. Further, in the parallel operation mode, so that the voltage _{V L} to be regenerated is between the first voltage _{V 1} of the second voltage _{V 2,} the first switch SW1 and second switch SW2 to PWM control. Thus, the voltage for the motor 3 is to regenerate or power running, to an intermediate voltage of the first voltages V ₁ and the second voltage V _2, the power supply device 1, the first switch SW1, the second switch The intermediate voltage mode in which the SW2 and the third switch SW3 are PWM controlled is set.

In the PWM control, the controller 1a controls the duty ratio of the first switch SW1, the second switch SW2, and the third switch SW3. The controller 1a includes a first voltages V ₁ supplied to or inverter 2 is regenerated from the inverter 2 in response to the intermediate voltage between the second voltage V ₂ to determine the duty ratio. Specifically, PWM control is performed so as to prevent a large current during a period in which each operation mode is switched and the charge voltage or the discharge voltage is switched. Furthermore, during discharging of the first battery 10 and the second battery 11 in the series operation mode, the third switch SW3 so as to generate an appropriate first voltage intermediate voltage V ₁ and the second voltage V ₂ to the inverter 2 PWM Control.

[Operation of Power Supply Device 1]
Next, the operation of the above-described power supply device 1 will be described. In the following, the operation during motor power generation will be described first, and then the operation during motor power running will be described.

"Operation during motor power generation"
First, referring to FIG. 5, when the motor 3 is in the power generation (regeneration) state, the output voltage V _BAT of the power storage unit 1b is changed from the second voltage V ₂ (high voltage) to the first voltage V ₁ (low voltage). A case of switching will be described. That is, an example of the operation state of each switch and the voltage and current state of each part when switching from the series connection state of FIG. 4 to the parallel connection state of FIG. 3 will be described.

  However, let the passing current between the power storage unit 1b and the inverter 2 be I, and let the direction flowing in the direction from the inverter 2 to the power storage unit 1b be the positive direction.

7, a power generation state of the motor 3, the case of switching the output voltage V _BAT of the power storage unit portion 1b from the second voltage V ₂ to the first voltage V _1, shows a flow chart of a switch control by the controller 1a performs . Here, whether or not the motor 3 is in the power generation state is determined by, for example, the sign of the current detection value of the current sensor 30 or the motor torque command value.

Even when the output voltage V _BAT is switched from the second voltage V ₂ to the first voltage V ₁ when the motor 3 is in a power running state, a current flows from the smoothing capacitor 4 to the motor 3 side, and the voltage across the input terminals of the inverter 2 Since _VINV decreases, a problem due to an abnormal current on the power storage unit portion 1b side hardly occurs. Therefore, this control may not be performed when the motor 3 is in the power running state.

In step S1, the power supply device 1 is set to an initial state before starting the voltage switching control. In the initial state before the voltage switching control (t ₋₁ to t _{0 in} FIG. 8), the first switch SW1 and the second switch SW2 are in the off state, the third switch SW3 is in the on state, and the storage unit unit 1b Both the output voltage V _BAT and the input terminal voltage V _INV of the inverter 2 are the second voltage V ₂ . In this case, when the generated power of the motor 3 and P _V, the current I flowing through the energy storage unit portion 1b is expressed by the following equation (1).

In the next step S2, immediately after the start of the voltage switching control (t _{0 in} FIG. 8), the controller 1a first turns off the third switch SW3 and turns on the first switch SW1 and the second switch SW2. . At this time, the controller 1a may provide a blank period in which all the switches are turned off before setting the switch state.

This state is the parallel operation mode in FIG. The controller 1a is set such that the following equation (2) the output voltage _{V BAT} of the power storage unit 1b (first voltage output means).

At this time, the voltage V _INV between the input terminals of the inverter 2 is expressed by the following equation (3).

Therefore, in step S2, between the power storage unit section 1b and the inverter 2, it takes a difference potential difference between the input terminal voltage V _INV of the output voltage V _BAT and the inverter 2 of the power storage unit portion 1b. Current I flowing between power storage unit portion 1b and inverter 2 gradually increases according to the following equation (4) from the potential difference.

In step S4, the controller 1a determines whether or not the current I is equal to or greater than a first predetermined value I ₁ (first switching current) specified in advance. If current I is smaller than the predetermined value _{I 1,} the flow returns to step S3. When current I becomes a first predetermined value _{I 1} or more, the process proceeds to step S5, and turns off the first switch SW1 and second switch SW2, turns on the third switch SW3 _(t 1 in FIG. 5) ( Second voltage output means). Then, the output voltage _{V BAT} of the power storage unit portion 1b is represented by the following formula (5).

Since the charge from the smoothing capacitor 4 in the inverter 2 is drawn out, the input terminal voltage V _INV of the inverter 2 at this time, the second voltage V ₂ or less as in the following equation (6).

For this reason, in step S6, the current I does not suddenly become zero due to the potential difference between the power storage unit 1b and the inverter 2 as shown in the equation (7), but gradually according to the following equation: Decrease.

In step S7, the controller 1a determines whether or not the current I between the power storage unit unit 1b and the inverter 2 is equal to or less than a second predetermined value I ₂ (second switching current) specified in advance. If current I is greater than a second predetermined value _{I 2,} the flow returns to step S6. If the current I is less than or equal to the _second predetermined value I2, the process proceeds to step S8.

In step S8, the controller 1a determines that the potential difference (V _INV −V ₁ ) between the input terminal voltage V _INV and the first voltage V ₁ of the inverter 2 measured by the voltage sensor 40 is greater than the control end potential difference ΔV specified in advance. Judge whether it is large or not. When the potential difference (V _INV −V ₁ ) is larger than the control end potential difference ΔV, the process returns to step S2, the third switch SW3 is turned off, and the first switch SW1 and the second switch SW2 are turned on (FIG. 8). T ₂ ). Then, since the condition of the equation (4) is satisfied again, the current I gradually increases.

Thus, while the potential difference between the input terminal voltage V _INV of the inverter 2 and the first voltage V ₁ is larger than the control end potential difference ΔV, that is, the input terminal voltage V _INV of the inverter 2 is in the vicinity of the first voltage V _1. The process from step S2 to step S7 is repeated by the controller 1a until the voltage becomes. Thereby, the voltage V _INV between the input terminals of the inverter 2 is gradually lowered from the second voltage V ₂ .

  Thus, repeating the processing from step S2 to step S7 causes the first voltage output means (S2) and the second voltage output means (S4) to operate alternately, and the output voltage of the power storage unit section 1b is changed to the first. Voltage switching means for repeatedly switching between the voltage and the second voltage is configured.

On the other hand, when the potential difference between the input terminal voltage V _INV of the inverter 2 and the first voltage V ₁ is equal to or less than the control end potential difference ΔV, the controller 1a turns off the third switch SW3 and sets the first switch SW1 in step S9. Then, the second switch SW2 is turned on to finish the control (t _{3 in} FIG. 8). Thus, during regeneration of the motor 3, the voltage between the power storage unit section 1b and the inverter 2 can be controlled to an intermediate voltage of the first voltages V ₁ and the second voltage V _2. Thereby, the electric power supply apparatus 1 can suppress the abnormal current generated at the time of voltage switching.

Incidentally, in the control during regeneration as described above, the average current passing through the time-averaged in the voltage switching control is adjusted first predetermined value I ₁ with a second predetermined value I _2. As the first predetermined value I ₁ increases, the average passing current increases, so that the speed at which charges are drawn from the smoothing capacitor 4 increases, and the input terminal voltage V _INV of the inverter 2 decreases earlier. However, the first predetermined value _{I 1,} the first switch SW1, a second switch SW2, is limited to a value that damage does not occur to the third switch SW3.

On the other hand, as the second predetermined value I ₂ decreases, the average passing current decreases, so that the speed at which charges are drawn from the smoothing capacitor 4 decreases, and the voltage V _INV between the input terminals of the inverter 2 decreases later. In order to extract charges from the smoothing capacitor 4, the average current value (I ₁ + I ₂ ) / 2 is set to be larger than the generated power amount P _V / 2V ₁ before the control of the equation (1). The second predetermined value I ₂ may be set to a value of P _{V /} first near voltages V ₁ as less than the amount of power generation P _{V /} first voltage V ₁ of the post-control completion. The value of the control end voltage difference ΔV, for example, may be set from 0.1% in the first value of the voltages _{V 1} to 30%.

As described above, the current passing through the switching of the output voltage of the first predetermined value I ₁ or more when power storage unit portion 1b to a second voltage V _2, the current passing through the second predetermined value I ₂ or less when the power storage unit switch the output voltage to the first voltage _{V 1.} Thereby, the electric current which flows from the inverter 2 to the electrical storage unit part 1b can be controlled, and voltage switching can be performed, suppressing an abnormal current. Further, it is possible to first predetermined value I ₁ with a second magnitude of a predetermined value I _2, sets the average current passing through during the voltage switching control arbitrarily.

"Operation during motor power running"
Next, the operation of the power supply device 1 when the motor 3 is in the power running state will be described with reference to FIGS. 9 and 10.

In case the motor 3 is in the power running state, when switching the output voltage V _BAT of the power storage unit portion 1b from the first voltages V ₁ to the second voltage V _2, i.e., the series connection state of FIG. 4 from the parallel connection state of FIG. 3 It is an example of the operation state of each switch in the case of switching, the voltage of each part, and a current state. However, contrary to the case of FIG. 8, the current I flowing between the power storage unit 1b and the inverter 2 flows from the power storage unit 1b in the direction of the inverter 2 as a positive direction.

Note that when the motor 3 is charging (regenerative) state, the output voltage V _BAT of the power storage unit section 1b be switched from the first voltages V ₁ to the second voltage V _2, the current from the motor 3 side to the smoothing capacitor 4 Since the voltage V _INV between the input terminals flows and rises, a problem due to an abnormal current on the power storage unit portion 1b side hardly occurs. Therefore, this control may not be performed when the motor 3 is in a charged state.

9, in case of switching from the first voltages V ₁ output voltage V _BAT of the power storage unit portion 1b in the power running state of the motor 3 to a second voltage V _2, a flowchart of a switch control by the controller 1a performs. Whether or not the motor 3 is in the power running state is determined by, for example, the sign of the current detection value of the current sensor 30.

In step S11, the power supply device 1 is set to an initial state before the start of voltage switching control. In the initial state before the voltage switching control (t _{−1 to} t _{0 in} FIG. 10), the third switch SW3 is in the off state, and the first switch SW1 and the second switch SW2 are in the on state. Further, the output voltage V _BAT of the power storage unit 1b and the input terminal voltage V _INV of the inverter 2 are both the first voltage V ₁ . In this case the power usage of the motor 3 and P _V, a current I between the power storage unit section 1b and the inverter 2 is represented by Equation (8).

In step S12, the controller 1a switches the first switch SW1 and the second switch SW2 to the off state and the third switch SW3 to the on state immediately after the start of the voltage switching control (t _{0 in} FIG. 7). It is set as following equation (9) the output voltage _{V BAT} of the power storage unit 1b. Here, the controller 1a, by performing PWM control for the third switch SW3, the second voltage _{V 2} as the output voltage _{V BAT,} the intermediate voltage of the first voltages _{V 1} and the second voltage _{V 2} adjust.

  At this time, the controller 1a may provide a blank period in which all the switches are turned off before the third switch SW3 is turned on. Accordingly, it is possible to avoid that the first switch SW1 and the third switch SW3 or the second switch SW2 and the third switch SW3 are turned on simultaneously when the power storage unit 1b generates the intermediate voltage. Thereby, it is possible to prevent a short circuit of the battery from occurring.

At this time, the voltage V _INV between the input terminals of the inverter 2 is expressed by the following equation (10).

For this reason, in step S13, a potential difference of a difference between the output voltage V _BAT of the power storage unit 1b and the voltage V _INV between the input terminals of the inverter 2 is applied between the power storage unit 1b and the inverter 2. Thereby, current I between power storage unit portion 1b and inverter 2 gradually increases from the potential difference according to the following equation (11).

In step S14, the controller 1a determines whether or not the current I between the power storage unit portion 1b and the inverter 2 is equal to or greater than a _first predetermined value I1 specified in advance. If current I is less than a first predetermined value _{I 1,} the flow returns to step S13. When current I becomes a first predetermined value _{I 1} or more, the process proceeds to step S15, the third switch SW3 are turned off, the first switch SW1, the second switch SW2 to the ON state _{(t 1} in FIG. 10 ). Then, the output voltage _{V BAT} of the power storage unit portion 1b is represented by the following formula (12). Here, the controller 1a may control the PWM control for the first switch SW1 and the second switch SW2.

Since the current flowing into the smoothing capacitor 4 in the inverter 2, the voltage V _INV between the input terminals of the inverter 2 becomes the first voltages V ₁ or more as in the following equation (13).

Therefore, in step S16, the current I between the power storage unit 1b and the inverter 2 suddenly becomes zero due to the potential difference between the power storage unit 1b and the inverter 2 as shown in the equation (14). Instead, it gradually decreases according to the following equation.

In step S17, the controller 1a determines whether or not the current I between the power storage unit unit 1b and the inverter 2 is equal to or less than a _second predetermined value I2 designated in advance. If current I between power storage unit 1b and inverter 2 is larger than _second predetermined value I2, the process returns to step S16. If current I between power storage unit 1b and inverter 2 is equal to or smaller than _second predetermined value I2, the process proceeds to step S18.

In step S18, the controller 1a is the potential difference between the second voltage _{V 2} and the input terminal voltage _{V INV} of the inverter 2 _{(V 2 -V INV)} is pre-specified control end voltage difference ΔV is greater than whether the determination To do. When the potential difference is larger than the control end potential difference ΔV, the process returns to step S12, and the controller 1a turns off the first switch SW1 and the second switch SW2 and turns on the third switch SW3 (t _{2 in} FIG. 10). ). Then, since the condition of the formula (11) is satisfied again, the current I between the power storage unit portion 1b and the inverter 2 gradually increases.

In this way, from step S12 to step S12, the potential difference (V ₂ −V _INV ) is larger than the control end potential difference ΔV, that is, until the voltage V _INV between the input terminals of the inverter 2 becomes a voltage near the second voltage V _2. The process up to S17 is repeated. Thereby, the voltage V _INV between the input terminals of the inverter 2 is gradually boosted from the first voltage V ₁ .

On the other hand, if the potential difference (V ₂ −V _INV ) is equal to or less than the control end potential difference ΔV, the controller 1a turns off the first switch SW1 and the second switch SW2 and turns on the third switch SW3 in step S19. The control is terminated (t _{3 in} FIG. 10). In this way, while the motor 3 is suppressed abnormal current at the time of power running, it is possible to terminate the voltage switching of the output voltage of the power storage unit 1b (from the first voltages V ₁ to the second voltage V _2).

Here, the controller 1a is a second voltage V ₂ after boosting, can be in any intermediate voltage higher than the first voltage V _1. In this case, by the controller 1a performs PWM control for the third switch SW3, an input terminal voltage _{V INV} of the inverter 2, thereby adjusting the intermediate voltage of the first voltages _{V 1} and the second voltage _{V 2.} Thus, after the output voltage V _BAT of the power storage unit portion 1b is raised to a second voltage V _2, the controller 1a may be from the power storage unit portion 1b to any intermediate voltage the voltage supplied to the inverter 2.

Thereafter, in order to maintain the intermediate voltage after the boost, the controller 1a continues the PWM control with respect to the third switch SW3 in the state of the series operation mode. That is, as shown in FIG. 11, the duty ratio is adjusted so that the voltage V _INV between the input terminals of the inverter 2 becomes an intermediate voltage between the first voltage V ₁ and the second voltage V _2, and the third switch SW 3 On the other hand, PWM control is performed.

The average current passing through the time-averaged in the voltage switching control is adjusted first predetermined value I ₁ with a second predetermined value I _2. As the first predetermined value I ₁ increases, the average passing current between the power storage unit 1b and the inverter 2 increases, so that the speed at which the smoothing capacitor 4 is charged increases and the voltage between the input terminals of the inverter 2 increases. V _INV increases quickly. However, the first predetermined value _{I 1,} the first switch SW1, a second switch SW2, is limited to a value that damage does not occur to the third switch SW3.

On the other hand, as the second predetermined value I ₂ decreases, the average passing current between the power storage unit 1b and the inverter 2 decreases, so that the speed at which the smoothing capacitor 4 is charged becomes slower, and the input of the inverter 2 The terminal voltage V _INV decreases slowly. The first predetermined value I ₁ may be set larger than the current (P _V / V ₁ ) before the control in Expression (8). The second predetermined value I ₂ may be set to a value in the vicinity of P _V / 2V ₁ that is smaller than the current (P _V / 2V ₁ ) after the end of control. The value of the control end voltage difference ΔV, for example, may be set from 0.1% in the first value of the voltages _{V 1} to 30%.

As described above, when the passing current between the power storage unit section 1b and the inverter 2 is in the first predetermined value I ₁ or more switches the output voltage V _BAT of the power storage unit section 1b to the first voltage V _1, the current I when is a second predetermined value _{I 2} below, switches the output voltage _{V BAT} of the power storage unit portion 1b to a second voltage _{V 2.} Thereby, since the electric current which flows from the electrical storage unit part 1b to a load part (the inverter 2 and the motor 3) can be controlled, voltage switching can be performed, suppressing an abnormal current.

Further, it is possible to first predetermined value I ₁ with a second magnitude of a predetermined value I _2, to arbitrarily set the average passing current between the power storage unit section 1b and the inverter 2 in the voltage switching control.

[Effect of the embodiment]
As described above in detail, according to the power supply device 1 shown as an embodiment of the present invention, when the output voltage of the power storage unit portion 1b to an intermediate voltage of the first voltages V ₁ and the second voltage V ₂ The state in which the first switch SW1 and the second switch SW2 are subjected to pulse width control (PWM control) and the state in which the third switch SW3 is subjected to pulse width control (PWM control) are alternately repeated. Thus, according to the power supply device 1, the voltage at the time of discharge of the first battery 10 and the second battery 11 can be controlled to an intermediate voltage between the first voltages V ₁ and the second voltage V ₂ rather than excessive voltage . Therefore, according to this power supply device 1, it is possible to drive the load by outputting appropriate power from the power storage unit 1b.

  Moreover, according to this power supply device 1, since the voltage at the time of charging and discharging can be adjusted to an intermediate voltage, cost reduction can be achieved without providing a reactor or a relay between the power storage unit portion 1b and the inverter 2. Can do.

  Furthermore, according to the power supply device 1, the first switch SW1 and the second switch SW2 are provided between the period during which the first switch SW1 and the second switch SW2 are subjected to pulse width control and the period during which the third switch SW3 is subjected to pulse width control. A blank period is provided in which the switch SW2 and the third switch SW3 are all turned off. Thereby, it is possible to prevent a short circuit of the battery from occurring.

  Furthermore, according to the power supply device 1, the first battery 10 and the second battery 11 are connected in series and discharged with the first switch SW1 and the second switch SW2 turned off. In this case, the third switch SW3 is subjected to pulse width control (PWM control). Thereby, since necessary electric power can be supplied with respect to the inverter 2, the power conversion efficiency in the inverter 2 can be improved.

  The above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and various modifications can be made depending on the design and the like as long as the technical idea according to the present invention is not deviated from this embodiment. Of course, it is possible to change.

DESCRIPTION OF SYMBOLS 1 Power supply device 1a Controller 1b Power storage unit 1b Power storage unit part 2 Inverter 3 Motor 4 Smoothing capacitor 10 1st battery 11 2nd battery 13 Semiconductor switching element 14 Reverse parallel diode 20 Inverter drive circuit 30 Current sensor 40 Voltage sensor 50 Voltage sensor SW switch

Claims (3)

A power supply device having a power storage unit capable of outputting at least two voltages, wherein the power storage unit is connected to a terminal of a load unit,
First voltage output means for setting the output voltage of the power storage unit as a first voltage;
Second voltage output means for setting the output voltage of the power storage unit to a second voltage that is higher than the first voltage;
Voltage switching for alternately operating the first voltage output means and the second voltage output means when the output voltage of the power storage unit and the terminal voltage of the load section are set to an intermediate voltage between the first voltage and the second voltage. Means,
The power storage unit includes a first power storage unit and a second power storage unit, a first switch, a second switch, and a third switch, and when only the first switch and the second switch are turned on, When the first power storage unit and the second power storage unit are connected in parallel to the load unit, and only the third switch is turned on, the first power storage unit and the second power storage unit are turned on with respect to the load unit. 2 The power storage unit is configured to be connected in series, and the first switch, the second switch, and the third switch are provided in parallel with the semiconductor switching element and the semiconductor switching element, and the semiconductor switching element is turned on. Including an anti-parallel diode in which the reverse direction to the current direction when set to the state is the forward direction,
The voltage switching means is configured to control the pulse width of the first switch and the second switch when the output voltage of the power storage unit is set to an intermediate voltage between the first voltage and the second voltage; A power supply device characterized by alternately repeating a state in which the switch is subjected to pulse width control.   The voltage switching means includes the first switch and the second switch between a period during which the first switch and the second switch are subjected to pulse width control and a period during which the third switch is subjected to pulse width control. The power supply apparatus according to claim 1, wherein a blank period in which all the third switches are in an off state is provided.   The voltage switching unit is configured to discharge the first power storage unit and the second power storage unit connected in series with the first switch and the second switch in an off state. The power supply apparatus according to claim 1, wherein the third switch performs pulse width control.

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