JP2004007964A - Inverter circuit device for three-phase motor for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power loss while securing the operation stability of an inverter circuit for a three-phase motor which performs three-phase full wave rectification. <P>SOLUTION: In an inverter circuit device for a three-phase motor for a vehicle, a synchronous rectification control circuit 32, which performs synchronous rectification control by intermittently controlling each MOS transistors 21-26 of the three-phase inverter circuit 2, decides the on timing or off timing of an upper arm element 21 which rectifies a first phase voltage, based on the phase voltage different from the first phase voltage. Hereby, a highly reliable three-phase full wave rectification with low loss can be realized. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inverter circuit device for a dual-use three-phase rotating electric machine used for a hybrid vehicle, an eco-run vehicle, a fuel cell vehicle, an electric bicycle, and the like, and more particularly to power generation control thereof.
[0002]
2. Description of the Related Art
Patent Literature 1 discloses a three-phase full-wave rectifier circuit (also referred to as a three-phase inverter circuit in this specification) configured to rectify power generated by a three-phase rotating electric machine for a vehicle by using a MOS transistor, and an AC-side main electrode thereof. A MOS type three-phase rectifier circuit that reduces the power loss of a diode of the three-phase rectifier circuit (or a parasitic diode of the MOS transistor) by intermittently controlling the MOS transistor based on a potential difference between a voltage and a battery voltage. Propose that.
[0003]
However, in the above-described conventional MOS-type three-phase rectifier circuit, since the channel voltage drop of the MOS transistor after being turned on, that is, the potential difference between the AC-side main electrode voltage and the battery voltage is as small as about 0.1 V, for example, It is not easy to accurately determine the change in this potential difference between the AC-side main electrode voltage and the battery voltage in an electromagnetically harmful environment such as a vehicle generator, and it is difficult to perform the turning-off at the correct timing. The difficulties hindered its practical application.
[0004]
The MOS transistor forming the upper arm element of the conventional MOS type three-phase rectifier circuit will be specifically described as an example. When the AC main electrode voltage becomes higher than the battery voltage by a predetermined threshold or more, this MOS transistor is turned on. After being turned on, the voltage drop of this MOS transistor becomes as small as about 0.1 V, so that the MOS transistor is easily turned off, and it is possible that chattering may occur.
[0005]
Further, since there is a circuit delay time from the detection of the voltage to the end of turning on or off of the MOS transistor, in a high rotation region, a current reverse flow from the battery to the motor occurs, or the turning on of the MOS transistor is delayed. There are also problems that the ability to take out current is reduced, and that current flows through the parasitic diode of the MOS transistor to increase power loss.
[0006]
The present invention has been made in view of the above problems, and has as its object to reduce the power loss of an inverter circuit for a three-phase rotating electric machine that performs three-phase full-wave rectification while ensuring operation stability.
[0007]
[Patent Document 1] Japanese Patent No. 2959640
[0008]
[Means for Solving the Problems]
The inverter circuit device for a three-phase electric rotating machine for a vehicle according to the first aspect of the present invention, wherein the inverter circuit device is provided between a three-phase armature winding of a three-phase electric rotating machine for a vehicle and a DC power supply and at least the three-phase electric rotating machine. A three-phase inverter circuit for rectifying three phase voltages, which are induced voltages of the armature winding, and supplying power to the DC power supply; and a control circuit for intermittently controlling each switching element of the three-phase inverter circuit. The phase inverter circuit is an inverter circuit device for a three-phase rotating electrical machine for a vehicle having an upper arm element or a lower arm element made of a MOS transistor.
The control circuit may determine an ON timing or an OFF timing of the upper arm element that rectifies the first phase voltage based on the phase voltage different from the first phase voltage.
[0009]
That is, in the present invention, the intermittent timing of the MOS transistor of the self-phase is determined by using at least a phase voltage of a different phase different from the self-phase, instead of the potential difference between the two main electrode terminals as in the prior art. To solve the problem in the prior art that the potential difference between the two main electrode terminals becomes very small after turning on and it is not easy to detect the change, thereby realizing low-loss three-phase full-wave rectification with excellent operation reliability. be able to.
[0010]
Further explanation will be given.
[0011]
In the synchronous rectification technology that is the object of the present invention, of the intermittent control of a switching element such as a MOS transistor of a three-phase inverter circuit (or a multi-phase inverter circuit), determination of an off timing is particularly important. That is, the ON timing of the switching element is determined when the own AC-side main electrode voltage exceeds the DC-side main electrode voltage (up to a point where the AC-side main electrode voltage is slightly smaller than the DC-side main electrode voltage in consideration of switching delay). (It may be at the time of rising), that is, it can be reliably turned on at the optimum time.
[0012]
However, when the switching element is turned off, the difference between its own AC-side main electrode voltage and its DC-side main electrode voltage is very small (usually 0.1 V or less) because of the self-conduction. Even if the generated voltage (phase voltage) of the phase becomes smaller than the DC main electrode voltage, in a bidirectional conduction type switching element such as a MOS transistor, a favorable voltage change is caused by a current reverse flow from the DC main electrode to the AC main electrode. Cannot be detected.
[0013]
For this reason, as in the present invention, it is particularly preferable to turn off the switching element during the ON after a predetermined time delay from the ON timing of the other phase voltage as described above. As other phases to be detected, the timing error closest to the off-timing of the on-time switching element and the on-timing of the switching element of the phase that is simultaneous or preceding in time is most likely to cause a timing error. Most suitable for reduction.
[0014]
The other phase that best meets such a condition is a phase that is delayed by 120 degrees (in the case of three phases) from the phase in which the switching element is to be turned off. When the phase voltage having the largest voltage value changes in the order of U, V, and W, the off-timing of the U-phase upper arm element can be matched with the on-timing of the next V-phase upper arm element. In this way, the U-phase upper arm element can be turned on only by 120 degrees. In this case, since there is no time delay, it is possible to minimize the timing deviation due to the change in the number of rotations or the change in the generated voltage.
[0015]
Further, in the above description, when the own phase voltage rises to a predetermined value (preferably the battery voltage or slightly lower than the battery voltage), the upper arm element of the own phase is turned on, and the phase voltage of the subsequent phase is set to the predetermined value. (Preferably the battery voltage or slightly lower than it), the upper arm element control for instructing to turn off the upper arm element of the preceding phase at the point of time when it rises or when it is delayed for a predetermined period of time. Similarly, in the element control, the off-timing of the lower-arm element of an arbitrary phase can be determined based on the on-timing of the lower-arm element of another phase. However, since the lower arm element need not be turned on at the same time as the upper arm element of the same phase, the lower arm element of the same phase may be switched on and off at the timing for controlling the disconnection of the upper arm element.
[0016]
In a preferred aspect, the control circuit is configured to control the first phase voltage at a time when a second phase voltage delayed from the first phase voltage exceeds a predetermined first threshold voltage value or when a predetermined time elapses from the time. And turning off the upper arm element for rectifying the phase voltage.
[0017]
According to this configuration, the off-state of the upper-arm element of the predetermined phase is determined based on the rising timing of the phase voltage of the other phase that is shifted to a phase later than this phase, so that this off is preferable even in a strong electromagnetic noise environment. It can be performed at an appropriate timing. Also, even if the off-timing of the upper arm element is delayed due to the operation delay of the circuit system, it is possible to easily prevent the current from flowing backward from the battery to the rotating electric machine. The predetermined time may be fixed, or may be reduced as the number of rotations increases.
[0018]
Further explanation will be given.
[0019]
Particularly in this aspect, the upper arm that rectifies the first phase voltage at a time that is delayed by a predetermined time from a time when a second phase voltage that is delayed from the first phase voltage exceeds a predetermined first threshold voltage value It is preferable to instruct the turning off of the element. Here, assuming that a point in time at which the second phase voltage that lags behind the first phase voltage exceeds a predetermined first threshold voltage value is the ON timing of the upper arm element that rectifies the second phase voltage, The off-timing of the first-phase upper arm element is set with a predetermined time delay from the on-timing of the two-phase upper arm element. That is, the off-timing of the upper-arm element of a certain phase is higher than the on-timing of the upper-arm element of the succeeding (latest) phase (more precisely, the succeeding phase voltage exceeds a predetermined threshold). Delay for a predetermined time (from the point in time).
[0020]
When the predetermined time delay is not set, as described above, the three upper arm elements of the three-phase inverter circuit are turned on alternately by 120 degrees, and each phase voltage performs synchronous rectification for a period of 120 degrees. Will be. Hereinafter, this method is referred to as a 120-degree synchronous rectification method.
[0021]
However, in a normal vehicular alternator operated in a power generation suitable rotation speed range equal to or higher than the idle rotation speed, each phase voltage (AC side main electrode voltage of the upper arm element of each phase) is determined by the battery voltage (each After turning on beyond the DC side main electrode voltage of the upper arm element of the phase) or a predetermined voltage, it is normal that the battery voltage is still higher than the battery voltage even after a period of 120 degrees, and the battery charge period is usually close to 180 degrees. Is possible. Therefore, in the above-described 120-degree synchronous rectification method, only the energy that can be rectified by the power is wastedly generated. Therefore, if the off-timing of the upper arm element of the preceding phase is further delayed by a predetermined time after the voltage of the succeeding phase exceeds the predetermined threshold beyond the 120-degree synchronous rectification period, in other words, The waste of power generation can be reduced or eliminated, and power generation efficiency can be improved.
[0022]
In a preferred aspect, the control circuit sets an ON timing of the upper arm element for rectifying the first phase voltage to a predetermined second threshold voltage at which the first phase voltage is lower than the voltage of the DC power supply. Value, and during a period in which a second phase voltage that is later than the first phase voltage is lower than a predetermined third threshold voltage value, instructs to turn on the predetermined upper arm element. .
[0023]
According to this aspect, the delay of the ON timing of the upper arm element can be reduced by the operation delay of the circuit system, and the increase in power loss of the upper arm element can be suppressed, so that the circuit configuration can be simplified. . Of course, if the generator has a rotation angle sensor, it is possible to easily perform a delay from 120 degrees to a further required angle based on the detected rotation angle.
[0024]
In a preferred aspect, the control circuit turns on the MOS transistor when the rotation speed of the three-phase rotating electric machine is equal to or higher than a predetermined value. Loss increase can be suppressed. Also, at low rotation, turning on the MOS transistor can prevent a current from flowing backward from the battery to the rotating electric machine.
[0025]
In a preferred aspect, the threshold rotation speed is set to a rotation speed at which the phase voltage exceeds the voltage of the DC power supply. Therefore, when the phase voltage does not exceed the battery voltage and there is no power generation capability, the MOS transistor Is turned on, and the problem that the current flows backward can be prevented.
[0026]
The inverter circuit device for a three-phase rotating electric machine for a vehicle according to claim 6 as a second invention that solves the same problem as the first invention, comprises a three-phase armature winding of the three-phase rotating electric machine for a vehicle and a DC power supply. A three-phase inverter circuit interposed therebetween for rectifying at least three phase voltages that are induced voltages of the three-phase armature winding and supplying power to the DC power supply; A control circuit for controlling the three-phase inverter circuit, wherein the three-phase inverter circuit is an inverter circuit device for a three-phase rotary electric machine for a vehicle having an upper arm element formed of a MOS transistor.
The control circuit, when the first phase voltage exceeds a predetermined threshold voltage set lower than the battery voltage by a predetermined value, instructs to turn on the upper arm element that rectifies the first phase voltage. It is characterized by doing.
[0027]
That is, in the above-described conventional inverter circuit device for a synchronous rectification type three-phase rotary electric machine for a vehicle, the intermittent control is performed based on a comparison result between each phase voltage and a battery voltage, that is, a potential difference generated between both main electrodes of the MOS transistor. Therefore, chattering is likely to occur as described above, and the operation is delayed due to a circuit delay.
[0028]
Therefore, according to the present invention, each phase voltage is compared with a predetermined threshold voltage smaller than the battery voltage, and a command to turn on the MOS transistor serving as the upper arm element is issued. The threshold voltage may be a value having a positive correlation with the battery voltage, for example, a value obtained by dividing the battery voltage, or a predetermined constant voltage. With this configuration, it is possible to prevent the MOS transistor from being erroneously turned on due to electromagnetic noise or the like, and to reduce the adverse effect of the circuit delay.
[0029]
In this case, the MOS transistor is instructed to be turned on before its own phase voltage has not yet exceeded the battery voltage. However, because the phase voltage waveform is a substantially rectangular wave and the circuit delay, No problem arises.
[0030]
In a preferred aspect, the control circuit is configured to control the second phase in which the first phase voltage is lower than a predetermined second threshold voltage value lower than the voltage of the DC power supply and the second phase lags behind the first phase voltage. During a period in which the voltage is higher than a predetermined third threshold voltage value, an instruction is given to turn on the lower arm element for rectifying the first phase voltage. According to this aspect, it is possible to reduce the delay of the on-timing of the lower arm element due to the operation delay of the circuit system, and to suppress an increase in the power loss of the lower arm element.
[0031]
In a preferred aspect, the control circuit is configured to control the time from when the first phase voltage exceeds a predetermined first threshold voltage value to when the second phase voltage exceeds the first threshold voltage value. The first phase voltage dominant time is counted, a delay time is set as a function value having a positive correlation with the first phase voltage dominant time, and the second phase voltage is a predetermined first threshold voltage. At the time when the delay time has elapsed from the time when the value exceeds the value, the upper arm element for rectifying the first phase voltage is commanded to be turned off. Thereby, the delay time can be appropriately set according to the fluctuation of the rotation speed.
[0032]
That is, in this embodiment, the time from when the phase voltage of the preceding phase exceeds the threshold voltage value to when the phase voltage of the succeeding phase exceeds the threshold voltage value is counted, and this time (the first phase) is counted. The delay time is set as a function value having a positive correlation with the voltage dominance time. Further explanation will be given.
[0033]
Obviously, the first phase voltage dominant time varies inversely with the generator speed. For example, in the case of three phases, the first phase voltage dominant time is 1/3 of one cycle thereof which is inversely proportional to the frequency of the three-phase AC voltage proportional to the rotation speed. Therefore, by setting the delay time as a function value having a positive correlation with the first phase voltage dominant time, the upper arm element of each phase of the three-phase inverter circuit can be turned on with respect to the phase voltage cycle even if the rotation speed changes. Variations in the period ratio can be suppressed. Due to the conduction of the upper arm element during this delay time, the upper arm element can perform synchronous rectification over a period of 120 degrees or more, so that power generation efficiency can be improved.
[0034]
In the above description, the upper arm element is described. However, since the upper arm element and the lower arm element of the three-phase inverter circuit are normally driven at the opposite timing in synchronization with each other, the lower arm element is also described above. It can be controlled similarly to the control of the arm element. Further, similarly to the upper arm element, the lower arm element of a certain phase may be turned off with a predetermined time delay from the on of the lower arm element of a phase later than the lower arm element.
[0035]
In a preferred aspect, the control circuit sets a half period of the first phase voltage dominant time as the delay time. By doing so, it is possible to suppress the reverse current flowing through the upper arm element of any phase of the three-phase inverter circuit, and the calculation of the delay time is simplified.
[0036]
In a preferred aspect, the control circuit sets 遅 延 of the first phase voltage dominant time as the delay time. This makes it possible to obtain an appropriate ON time of the upper arm element without complicating the calculation of the delay time.
[0037]
In a preferred aspect, the control circuit multiplies the first phase voltage dominant time counted by a counter as a built-in timer by a predetermined coefficient (less than 0.5) to obtain the delay time. This makes it possible to perform optimal synchronous rectification without significantly complicating the delay calculation.
[0038]
In a preferred aspect, the control circuit decreases the coefficient when the first phase voltage dominance time is long, and increases the coefficient when the first phase voltage dominance time is short. This makes it possible to achieve more optimal synchronous rectification with a simple configuration. This will be further described below.
[0039]
How much of the 360-degree period (electrical angle 2π) occupies a period in which the phase voltage (more precisely, the inter-phase electromotive force of the generator) is higher than the battery voltage (hereinafter, also referred to as a power generation phase period). Is a function value having a positive correlation (substantially proportional) to the rotating machine speed because this phase voltage has a positive correlation with the rotating machine speed.
[0040]
Since the ON period of the upper arm element of a certain phase is the sum of the first phase voltage dominant time and the delay time, the ratio of the total to 360 degrees is that the power generation possible phase period is 360 degrees period (electrical angle). 2π) is ideal for synchronous rectification. Therefore, it is preferable that the delay time is a function value having an optimum correlation with the rotating speed of the rotating machine.
[0041]
Here, the rotation speed of the rotating machine can be easily input in inverse proportion to the time between the time when the AC main electrode voltage of the upper arm element of the adjacent two phases exceeds the predetermined threshold, that is, the first phase voltage dominant time. Parameter. As a result, the above-described delay time becomes a function value having a negative correlation with the rotation speed.
[0042]
It is estimated that the shorter the first phase voltage dominant time is, the higher the number of revolutions is, so that the generated voltage (phase voltage) is large. It is estimated that the period during which the phase voltage exceeds the battery voltage occupies an electrical angle of 2π is large, and the delay is delayed. Increase time relatively. Conversely, it is estimated that the longer the first phase voltage dominant time is, the lower the number of revolutions is, so the generated voltage (phase voltage) is small, and that the period during which the phase voltage exceeds the battery voltage and occupies the electrical angle 2π is small. And the delay time is relatively reduced. Thereby, the delay time can be set appropriately. Of course, the delay time does not exceed 60 degrees.
[0043]
In a preferred aspect, the control circuit decreases the coefficient when the duty of the switching element for controlling the field current of the rotating electric machine is small, and increases the coefficient when the duty is large. This makes it possible to achieve more optimal synchronous rectification with a simple configuration.
[0044]
This will be further described below.
[0045]
A period during which the generated voltage (phase voltage) of the rotating machine of the field current conduction type is higher than the battery voltage (hereinafter also referred to as a power generation possible phase period) occupies what percentage of the 360-degree period (electric angle 2π). Since the power generation voltage (phase voltage) is a function value having a positive correlation with the field current, it is a function value having a positive correlation (substantially proportional) with the field current.
[0046]
Since the ON period of the upper arm element of a certain phase is the sum of the first phase voltage dominant time and the delay time, the ratio of the total to 360 degrees is that the power generation possible phase period is 360 degrees period (electrical angle 2π). It is the ideal of synchronous rectification that it becomes equal to the occupying ratio. Therefore, it is preferable that the delay time be a function value having an optimum correlation with the field current.
[0047]
Here, the field current is a parameter that can be easily input that is approximately proportional to the duty of the switching element for switching the field current. As a result, the above-mentioned delay time becomes a function value having a positive correlation with the duty. That is, since the magnitude of the field current is a function value having a positive correlation with the duty of the switching transistor that controls the switching of the field current, the field current can be estimated from the duty.
[0048]
Thus, the generated voltage can be predicted from the field current thus obtained. It is not necessary to estimate the field current in the magnet generator. In addition, since the change in the generated current changes the terminal voltage, that is, the phase voltage of the generator according to the change in the voltage drop inside the generator, the above-described prediction of the generated voltage may be further adjusted by the electric parameter related to the generated current. it can. As a result, the delay time becomes a function value having a positive correlation with the duty. Of course, the delay time does not exceed 60 degrees.
[0049]
Therefore, it is estimated that the larger the duty is, the larger the generated voltage (phase voltage) is, and the longer the period during which the phase voltage exceeds the battery voltage occupies the electrical angle 2π is, the longer the delay time is relatively increased. Is preferred. Conversely, it is estimated that the smaller the duty is, the smaller the generated voltage (phase voltage) is, and that the period during which the phase voltage exceeds the battery voltage occupies the electrical angle 2π is small, and the delay time is relatively reduced. Is preferred.
[0050]
In addition, the generated voltage (phase voltage) of the armature coil is related to the first phase voltage dominance time and the duty, and the magnitude of the generated voltage and the optimal delay time have a positive correlation. And the delay time may be stored as a map or a function, and the optimum delay time may be calculated based on the map or the function. By doing so, it is possible to conduct the upper arm element for most of the time when the phase voltage is higher than the battery voltage, thereby improving the power generation efficiency (reducing the circuit loss) in the synchronous rectification of the three-phase inverter circuit. can do.
[0051]
In a preferred aspect, the control circuit is configured to control a rotation angle incorporated in the three-phase electric rotating machine for a vehicle at a time when a second phase voltage delayed from the first phase voltage exceeds a predetermined first threshold voltage value. A rotation angle value for starting counting is obtained from a sensor, a rotation angle amount corresponding to the predetermined time is added to the rotation angle value for starting counting, and a rotation angle value for off-timing is calculated. When the rotation angle input from the controller reaches the rotation angle value for the off-timing, a command is issued to turn off the upper arm element that rectifies the first phase voltage.
[0052]
That is, in this embodiment, the phase of the lagging phase is set by the magnitude of the rotation angle (also referred to as the rotation angle amount) corresponding to the delay time set by the various methods described above or set as a fixed value. It is delayed from the time when the upper arm element exceeds the first threshold value (often referred to as the on-timing of the upper arm element in the lagging phase). Therefore, in this embodiment, the rotating electric machine needs a rotation angle sensor for detecting the rotation angle.
With this configuration, the off-timing of the upper arm element can be delayed by an accurate rotation angle amount corresponding to the set delay time.
[0053]
In a preferred aspect, the control circuit instructs the upper arm element to rectify the first phase voltage when the first phase voltage reaches a predetermined threshold value, and the first phase voltage Command the off-state of the upper arm element that rectifies the first phase voltage after the predetermined time from the time when the second phase voltage that is later exceeds the predetermined first threshold voltage value, and sets the first phase voltage to The upper arm element to rectify is commanded to turn off the lower arm element in phase with the upper arm element to rectify the first phase voltage at a point in time preceding the command to turn on the upper arm element by a predetermined dead time. At a point in time which is delayed by a predetermined dead time from a point in time when the upper arm element for rectifying a one-phase voltage is commanded to turn off, a command for turning on a lower arm element in phase with the upper arm element for rectifying the first phase voltage is given. I do.
[0054]
In this way, the lower arm element in phase with the upper arm element can be easily intermittently controlled, and simultaneously the upper and lower arm elements in phase can be reliably prevented from being simultaneously turned on.
[0055]
BEST MODE FOR CARRYING OUT THE INVENTION
[0056]
Embodiment 1
Embodiment 1 will be described below with reference to FIG.
[0057]
(Overall explanation)
1 is a three-phase brushless DC motor composed of a field winding synchronous machine, 2 is an inverter circuit, 3 is a controller, 4 is a field current controller, 5 is a resolver as a rotation angle sensor, 6 is a smoothing capacitor, and 7 is a current. A sensor 8 is a field current switch composed of a MOS transistor for interrupting the field current, and 9 is a battery.
[0058]
The three-phase brushless DC motor 1 is formed by connecting a U-phase winding 11, a V-phase winding 12, and a W-phase winding 13 in a star connection, and is wound around a rotor to generate a desired field current from a field current controller. It has a field coil 14 to be energized.
[0059]
The inverter circuit 2 is a three-phase inverter circuit that converts a DC power supply voltage supplied between the both ends of the battery VB + and VB− during a motor operation to a three-phase AC voltage and functions as a three-phase full-wave rectifier circuit during a power generation operation. Reference numerals 21 to 23 denote upper-arm side semiconductor switching elements, 24 to 26 denote lower-arm side semiconductor switching elements formed of MOS transistors, and D denotes a flywheel diode formed of a parasitic diode, but a dedicated diode may be provided.
[0060]
The controller 3 performs PWM control of each of the MOS transistors 21 to 26 of the three-phase inverter circuit 2 during electric operation based on signals from the resolver 5 and the current sensor 7 and a power generation command and an electric command from a vehicle control device (not shown). , A synchronous rectification control circuit 32 for synchronously rectifying the MOS transistors 21 to 26 during power generation, a PWM signal output from the MG control circuit 31 during electric operation, and power generation. A gate drive circuit 33 which amplifies the power of the synchronous rectification signal output from the synchronous rectification control circuit 32 and applies it to the gate electrode terminals of the MOS transistors 21 to 26 individually.
[0061]
The MG control circuit 31 PWM-modulates the energization phase signal of each phase based on the phase from the resolver 5 with the duty ratio determined based on the difference between the current from the current sensor 7 and the target current, based on the PWM carrier signal. To determine the PWM signal.
[0062]
The principle and circuit configuration of this kind of PWM electric control operation are already well known, and the MG control circuit 31 and the gate drive circuit 33 are no longer well known and are not the gist of this embodiment, so detailed description thereof will be omitted. I do.
[0063]
The field current control device 4 is a circuit called a normal alternator regulator, and performs feedback control of a field current value in order to keep the terminal voltage VB + of the battery 9 constant. The description is omitted because it is the same as that of the regulator.
[0064]
Needless to say, the resolver 5 can be changed to a magnetic rotation angle sensor or an optical rotation angle sensor. The smoothing capacitor 6 is provided with a pair of the three-phase inverter circuit 2 for reducing the effect of switching surge voltage caused by the switching operation of the inverter circuit 2 on a DC power supply (not shown) or reducing electromagnetic wave noise radiated outside. It is composed of a large-capacity capacitor connected between DC power supply terminals.
[0065]
The current sensor 7 detects the input current of the inverter circuit 2. In this embodiment, a low-resistance element is used to simplify the circuit. However, it is needless to say that a hall element may be used.
[0066]
During the power generation operation, the synchronous rectifier circuit 32 rectifies the three-phase power generation voltage by intermittently controlling each of the MOS transistors 21 to 26 of the three-phase inverter circuit 2 based on each phase voltage VU, VV, VW. 9 is fed.
[0067]
(Description of synchronous rectification control)
The synchronous rectification control which forms the gist of this embodiment will be described in detail below. FIG. 2 shows a synchronous rectification control circuit 32 of this embodiment.
[0068]
The U-phase voltage VU is compared with a threshold voltage value Vth (set to about half of the battery voltage VB in this embodiment) by a comparator 321U through a current limiting resistor r. The threshold voltage value Vth is compared with the threshold voltage value Vth by the comparator 321V through r and inverted by the inverter circuit 323V, and the comparison result is applied to the gate electrode terminal of the MOS transistor 21 through the OR circuit 324U and the inverter circuit 325U.
[0069]
As a result, MOS transistor 21 performs an operation of turning on only during a period when U-phase voltage VU is higher than threshold voltage Vth and V-phase voltage VV is lower than threshold voltage Vth.
[0070]
Thereby, as shown in FIG. 3, when U-phase voltage VU becomes higher than half of the battery voltage, an instruction to turn on MOS transistor 21 is issued. Note that the waveform of each phase voltage for charging the battery through the three-phase full-wave rectifier circuit is a substantially rectangular wave, and the time when the U-phase voltage VU actually exceeds the battery voltage and the time when the U-phase voltage VU is half of the battery voltage Since the time difference from when the voltage exceeds the threshold voltage value Vth) is small and the signal delay exists, the backflow from the battery 9 when the MOS transistor 21 is turned on can be almost ignored.
[0071]
Next, MOS transistor 21 is instructed to turn off early when V-phase voltage VV becomes greater than half of the battery voltage before U-phase voltage VU becomes smaller than half of the battery voltage. Thus, as long as the MOS transistor 21 is on, the potential difference between the two main electrode terminals of the MOS transistor 21 is as small as about 0.1 V, so that it is difficult to accurately determine the off-timing based on the change in the potential difference. There is no such problem.
[0072]
However, in this embodiment, since the MOS transistor 21 is turned off at the rising edge of the V-phase voltage VV, the turning-off of the MOS transistor 21 slightly precedes, and thereafter, the U-phase voltage VU is actually reduced to the battery voltage +0. Until the voltage drops to about 75 V, a diode rectification period using the parasitic diode of the MOS transistor 21 occurs, and the power loss increases as compared with the ideal synchronous rectification. Therefore, the MOS transistor 21 may be turned off after a predetermined time delay from the rising edge of the V-phase voltage VV.
[0073]
FIG. 4 shows an overall circuit diagram of the synchronous rectification control circuit 32.
[0074]
The MOS transistors 24 to 26 forming the lower arm element are controlled similarly to the MOS transistors 21 to 23 forming the upper arm element.
[0075]
324U ', 324V' and 324W 'are OR circuits having the same function as the OR circuit 324U, and 325U', 325V 'and 325W' are inverter circuits having the same function as the inverter circuit 325U.
[0076]
(Modification)
A modified embodiment will be described below with reference to FIG.
[0077]
In this modification, a two-input OR circuit 324U is replaced with a three-input OR circuit 328 in the circuit shown in FIG. 2, and an fV converter 326 and a comparator 327 are added.
[0078]
The fV converter 326 outputs an analog output voltage proportional to the frequency of the AC signal voltage output from the resolver 5 as a rotation speed proportional voltage. The comparator 327 compares the rotation speed proportional voltage with a predetermined threshold voltage value Vth2, and inputs the comparison result to a three-input OR circuit 328.
[0079]
Therefore, until the rotation speed of the generator exceeds the threshold rotation speed corresponding to threshold voltage value Vth2, the output voltage of comparator 327 is at a high level, OR circuit 328 outputs a high level, and inverter circuit 325U Outputs a low level, so that the MOS transistor 21 is not turned on. Similarly, when the OR circuits 324V, 324W, 324U ', 324V', and 324W 'shown in FIG. 4 are also changed to such three-input OR circuits, the MOS transistors 21 to 26 are erroneously turned on at a low rotation speed. As a result, no reverse current flows from the battery.
[0080]
The threshold rotation speed corresponding to the threshold voltage value Vth2 is preferably set such that the peak value of the phase voltage at this threshold rotation speed corresponds to the battery voltage or exceeds it by a predetermined value. It is.
[0081]
Embodiment 2
Another embodiment will be described below. In this embodiment, the synchronous rectification control circuit 32 shown in FIG. 1 is configured as a microcomputer, and an input signal related to a generated voltage is input to the synchronous rectification control circuit 32, and the synchronous rectification control circuit 32 calculates a delay time. The main point is that the ON period of each of the upper arm elements 21 to 23 is extended by 120 degrees or more by the delay time.
[0082]
FIG. 6 is a timing chart showing the waveform of the phase voltage. Vu is the electromotive force of a three-phase star connected U-phase armature coil, Vv is the electromotive force of a three-phase star connected V-phase armature coil, and Vw is a three-phase star connected W-phase armature coil. The electromotive force of AC-side main electrode voltage of U-phase upper arm element of the three-phase inverter circuit (referred to as U-arm voltage), AC-side main electrode voltage of V-phase upper arm element (referred to as V-arm voltage), AC-side main electrode voltage of W-phase upper arm element The electrode voltage (referred to as the W arm voltage) exceeds the battery voltage only for a period close to 180 degrees because the parasitic diode of the MOS transistor forming each arm element of the three-phase inverter circuit is on.
[0083]
Next, a process for determining the off-timing of the upper arm element and the lower arm element of the three-phase inverter circuit will be described. The on-timing of these elements can be easily determined when the AC main electrode voltage of the upper arm element exceeds the threshold voltage, as described above, and thus will not be described here.
[0084]
First, in step S100, the delay time ΔT is set by the various methods described above. Next, it is checked whether or not the upper arm element of any phase is turned on (or whether or not the upper arm element of any phase exceeds a predetermined threshold) (S102). Returning, if YES, the timer in which the delay time ΔT is set is started, and after the delay time ΔT, the upper arm element of the phase preceding the phase of the turned on upper arm element is turned off (S104). Next, after a predetermined short time has elapsed, the lower arm element of the preceding phase is turned on, and the process returns to step S100 (S106).
[0085]
Embodiment 3
Another embodiment will be described below. In this embodiment, the synchronous rectification control circuit 32 shown in FIG. 1 is configured as a microcomputer, and the upper arm element is turned off based on a rotation angle signal input from a rotation angle sensor built in the rotating electric machine.
[0086]
FIG. 8 illustrates a process of determining the off timing of the upper arm element and the lower arm element of the three-phase inverter circuit. The on-timing of the upper arm element can be easily determined when the AC main electrode voltage of the upper arm element exceeds the threshold voltage as described above, and is not described here.
[0087]
First, in step S200, the delay angle amount (rotation angle amount) Δθ corresponding to the delay time ΔT described above is set by the various methods described above. Next, it is checked whether or not the upper arm element of any phase has turned on (or whether or not the upper arm element of any phase has exceeded a predetermined threshold) (S202). Returning, if YES, the value of the rotation angle (rotation angle value for starting counting) at this time is read from the rotation angle sensor (S204).
[0088]
Next, the delay angle amount Δθ is added to the rotation angle value for counting start to calculate a rotation angle value for off timing (S206), and the rotation angle input from the rotation angle sensor is used for the off timing. After waiting until the rotation angle value is reached (S208), the upper arm element of the preceding phase is turned off (S210), and after a predetermined dead time, the lower arm element in phase with the turned off upper arm element is turned on (S212). .
[0089]
(Description of OFF control example of lower arm element)
The turning off of the lower arm element is performed by determining the turning on of the upper arm element of the same phase, and the upper arm element can be turned on after a lapse of a predetermined dead time from this execution.
[0090]
(Modification)
In the inverter circuit device for a three-phase rotating electric machine for a vehicle according to the present invention, the three-phase inverter circuit can be operated in the electric mode. Alternatively, only the diode may be used. Further, the generator may be an ordinary Randall-pole type generator.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an inverter circuit device for a three-phase rotary electric machine for a vehicle used for control of a first embodiment.
FIG. 2 is a circuit diagram showing a part of the synchronous rectification control circuit of FIG.
FIG. 3 is a timing chart showing an operation of the synchronous rectification control circuit of FIG. 2;
FIG. 4 is a circuit diagram showing the entire synchronous rectification control circuit of FIG. 1;
FIG. 5 is a circuit diagram showing a modified embodiment.
FIG. 6 is a waveform diagram of a phase voltage.
FIG. 7 is a flowchart for determining an off timing according to the second embodiment.
FIG. 8 is a flowchart for determining an off timing according to the third embodiment.
[Explanation of symbols]
1 Three-phase brushless DC motor (three-phase rotating electric machine for vehicles)
2. Inverter circuit (three-phase inverter circuit)
3 controller (control circuit)
5 Resolver
9 Battery (DC power supply)
11 to 13 phase winding
21-23 MOS transistor on upper arm side
24 to 26 MOS transistor on lower arm side

Claims (15)

The three-phase armature winding of the vehicular three-phase rotating electric machine is interposed between the DC power supply and at least three phase voltages that are induced voltages of the three-phase armature winding and rectified to supply power to the DC power supply. A three-phase inverter circuit, and a control circuit for intermittently controlling each MOS transistor constituting the three-phase inverter circuit,
The three-phase inverter circuit is an inverter circuit device for a three-phase rotating electrical machine for a vehicle having an upper arm element or a lower arm element made of a MOS transistor,
The control circuit includes:
The on-timing or the off-timing of the upper arm element for rectifying the first phase voltage is determined based on the phase voltage different from the first phase voltage. Inverter circuit device. The inverter circuit device for a three-phase rotary electric machine for a vehicle according to claim 1, wherein the control circuit comprises:
The upper arm element that rectifies the first phase voltage at a time when a second phase voltage delayed from the first phase voltage exceeds a predetermined first threshold voltage value or when a predetermined time has elapsed from the time. An inverter circuit device for a three-phase rotary electric machine for a vehicle, characterized by commanding turning off of the vehicle. The inverter circuit device for a three-phase rotary electric machine for a vehicle according to claim 1,
The control circuit includes:
The first phase voltage exceeds a predetermined second threshold voltage value lower than the voltage of the DC power supply, and a second phase voltage delayed from the first phase voltage is a predetermined third threshold voltage. An inverter circuit device for a three-phase rotary electric machine for a vehicle, wherein a command to turn on the predetermined upper arm element is issued during a period lower than the value. The inverter circuit device for a three-phase rotary electric machine for a vehicle according to claim 3,
The control circuit includes:
An inverter circuit device for a three-phase rotating electrical machine for a vehicle, wherein the MOS transistor is turned on when the rotation speed of the three-phase rotating electrical machine is equal to or more than a predetermined value. The inverter circuit device for a three-phase rotary electric machine for a vehicle according to claim 4,
The inverter circuit device for a three-phase rotating electric machine for a vehicle, wherein the threshold rotation speed is set to a rotation speed at which the phase voltage exceeds the voltage of the DC power supply. The three-phase armature winding of the vehicular three-phase rotating electric machine is interposed between the DC power supply and at least three phase voltages that are induced voltages of the three-phase armature winding and rectified to supply power to the DC power supply. A three-phase inverter circuit, and a control circuit for intermittently controlling each switching element of the three-phase inverter circuit,
The three-phase inverter circuit is an inverter circuit device for a three-phase rotating electrical machine for a vehicle having an upper arm element formed of a MOS transistor,
The control circuit includes:
When the first phase voltage exceeds a predetermined threshold voltage that is set smaller than the voltage of the DC power supply by a predetermined value, instructing that the upper arm element that rectifies the first phase voltage be turned on. An inverter circuit device for a three-phase rotary electric machine for vehicles, characterized by the following. The inverter circuit device for three-phase rotation for a vehicle according to claim 1,
The control circuit includes:
The first phase voltage is less than a predetermined second threshold voltage value lower than the voltage of the DC power supply, and a second phase voltage delayed from the first phase voltage is a predetermined third threshold voltage. An inverter circuit device for a three-phase rotary electric machine for a vehicle, wherein a command is issued to turn on the lower arm element for rectifying the first phase voltage during a period higher than a value. The inverter circuit device for three-phase rotation for a vehicle according to claim 2,
The control circuit includes:
A first phase voltage dominance which is a time from a time when the first phase voltage exceeds a predetermined first threshold voltage value to a time when the second phase voltage exceeds the first threshold voltage value; Count the time,
The delay time is set as a function value having a positive correlation with the first phase voltage dominant time,
A command is issued to turn off the upper arm element that rectifies the first phase voltage when the delay time has elapsed from the time when the second phase voltage exceeds a predetermined first threshold voltage value. Inverter circuit device for a three-phase rotating electric machine for vehicles. The inverter circuit device for three-phase rotation for a vehicle according to claim 8,
The control circuit includes:
An inverter circuit device for a three-phase rotary electric machine for a vehicle, wherein 1/2 of the first phase voltage dominant time is set as the delay time. The inverter circuit device for three-phase rotation for a vehicle according to claim 8,
The control circuit includes:
An inverter circuit device for a three-phase rotating electrical machine for a vehicle, wherein one-fourth of the first phase voltage dominant time is the delay time. The inverter circuit device for three-phase rotation for a vehicle according to claim 8,
The control circuit includes:
An inverter circuit device for a three-phase rotating electric machine for a vehicle, wherein the delay time is obtained by multiplying the first phase voltage dominant time counted by a counter as a built-in timer by a predetermined coefficient (less than 0.5). The inverter circuit device for three-phase rotation for a vehicle according to claim 11,
The control circuit includes:
The inverter circuit device for a three-phase rotary electric machine for a vehicle, wherein the coefficient is decreased when the first phase voltage dominance time is long, and the coefficient is increased when the first phase voltage dominance time is short. The inverter circuit device for three-phase rotation for a vehicle according to claim 11,
The control circuit includes:
An inverter circuit device for a three-phase electric rotating machine for a vehicle, wherein the coefficient is reduced when the duty of the switching element for controlling the field current of the rotating electric machine is small, and the coefficient is increased when the duty is large. . The inverter circuit device for three-phase rotation for a vehicle according to claim 2,
The control circuit includes:
At the point in time when the second phase voltage that is later than the first phase voltage exceeds a predetermined first threshold voltage value, a rotation angle value for counting starts from a rotation angle sensor built in the three-phase rotating electric machine for a vehicle. Acquired,
A rotation angle amount for off timing is calculated by adding a rotation angle amount corresponding to the predetermined time to the rotation angle value for counting start,
Three-phase rotation for a vehicle, wherein the upper arm element that rectifies the first phase voltage is commanded to be turned off when the rotation angle input from the rotation angle sensor reaches the rotation angle value for the off timing. Inverter circuit device for electric machinery. The inverter circuit device for a three-phase rotary electric machine for a vehicle according to claim 2,
The control circuit includes:
When the first phase voltage reaches a predetermined threshold value, the upper arm element for rectifying the first phase voltage is commanded to be turned on, and a second phase voltage delayed from the first phase voltage becomes a predetermined value. Command the off of the upper arm element rectifying the first phase voltage after the predetermined time from the time exceeding the first threshold voltage value,
Turn off the lower arm element in phase with the upper arm element that rectifies the first phase voltage at a point ahead of the time point when the upper arm element that rectifies the first phase voltage is commanded to turn on the upper arm element by a predetermined dead time. Command,
When the upper arm element for rectifying the first phase voltage is delayed by a predetermined dead time from the time when the upper arm element is commanded to be turned off, the lower arm element in phase with the upper arm element for rectifying the first phase voltage is turned on. An inverter circuit device for a three-phase rotating electrical machine for a vehicle, characterized in that:

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