JP7294114B2 - power conversion system - Google Patents

Description

The present disclosure relates to power conversion systems.

Conventionally, there is a switching power supply device disclosed in Patent Document 1. Patent Literature 1 aims to reduce switching loss in switching elements and reduce power consumption in a standby mode.

A switching power supply includes a sub-switching element, which has a smaller power capacity than the main switching element, in parallel with a main switching element that turns on and off the main current through the primary winding of the transformer. A control circuit for controlling on/off of these switching elements includes a main drive circuit, a sub-drive circuit, and an enable control circuit.

The main drive circuit generates a main drive signal for turning on and off the main switching element according to a control signal generated according to the output voltage obtained from the secondary winding of the transformer. The sub-drive circuit generates a sub-drive signal for turning on/off the sub-switching element according to the control signal. The enable control circuit then stops the operation of the main drive circuit when the load power consumption is less than a predetermined threshold.

JP 2017-22875 A

However, in Patent Document 1, there is a problem that the number of switching elements increases in order to reduce switching loss.

The present disclosure has been made in view of the above problems, and an object thereof is to provide a power conversion system capable of reducing switching loss while suppressing an increase in the number of switching elements.

In order to achieve the above objectives, the present disclosure
at least one power switching element (1 to n) constituting a power conversion circuit;
at least one drive circuit (11-1n) for driving the power switching element;
at least one switching power supply unit (50) for supplying power to the driving circuit;
a microcomputer (30) that outputs a drive signal for the drive circuit to drive the power switching element to the drive circuit,
The switching power supply unit changes its own operation state so as to correspond to the drive state of the power switching element based on drive information indicating the drive state of the power switching element ,
The switching power supply changes the switching frequency as an operating state, judges the load of the power switching element based on the drive information, and increases the switching frequency as the load increases.

The load of the switching power supply unit depends on the driving state of the power switching elements of the power conversion circuit. Therefore, since the present disclosure is configured as described above, it is possible to make the operating state of the switching power supply unit correspond to the driving state of the power switching element. Therefore, the present disclosure can reduce switching loss in the switching power supply without increasing the number of switching elements.

It should be noted that the symbols in parentheses described in the claims and this section indicate the correspondence with specific means described in the embodiments described later as one aspect, and are within the technical scope of the present disclosure. is not limited to

BRIEF DESCRIPTION OF THE DRAWINGS It is a circuit diagram which shows schematic structure of the power conversion system in embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows schematic structure of the power conversion system in embodiment. It is a circuit diagram showing an insulated power supply of the power conversion system in the embodiment. It is a wave form diagram which shows operation|movement of the power conversion system in embodiment. FIG. 10 is a waveform diagram showing the operation of the power conversion system in modification 1; FIG. 11 is a waveform diagram showing the operation of the power conversion system in modification 2; FIG. 11 is a waveform diagram showing the operation of the power conversion system in modification 3; FIG. 12 is a waveform diagram showing the operation of the power conversion system in modification 4; FIG. 12 is a waveform diagram showing the operation of the power conversion system in modification 5; FIG. 12 is a waveform diagram showing the operation of the power conversion system in modification 6; FIG. 12 is a waveform diagram showing the operation of the power conversion system in modification 7; FIG. 14 is a circuit diagram showing a schematic configuration of a voltage dividing circuit in modification 7; FIG. 12 is a waveform diagram showing the operation of the power conversion system in modification 8; FIG. 12 is a waveform diagram showing the operation of the power conversion system in modification 8; FIG. 12 is a block diagram showing a schematic configuration of a power conversion system in modification 9; FIG. 12 is a waveform diagram showing the operation of the power conversion system in modification 9; FIG. 12 is a block diagram showing a schematic configuration of a power conversion system in modification 9; FIG. 14 is a circuit diagram showing a schematic configuration of a power conversion system in modification 10; FIG. 20 is a waveform diagram showing the operation of the power conversion system in modification 10; FIG. 12 is a circuit diagram showing a schematic configuration of a power conversion system in modification 11; FIG. 21 is a waveform diagram showing the operation of the power conversion system in modification 12;

A plurality of modes for carrying out the present disclosure will be described below with reference to the drawings. In each form, the same reference numerals may be given to the parts corresponding to the matters described in the preceding form, and redundant description may be omitted. In each form, when only a part of the configuration is described, other parts of the configuration can be applied with reference to the previously described other modes.

(embodiment)
A power conversion system according to the present embodiment will be described with reference to FIGS. 1 to 4. FIG. In this embodiment, an example in which the power conversion system is applied to a vehicle (for example, a hybrid vehicle or an electric vehicle) provided with a rotating machine as a vehicle main engine is adopted. The power conversion system mainly includes a power converter 10 , a microcomputer 30 and an insulated power supply 50 .

As shown in FIG. 1, the power converter 10 constitutes a three-phase inverter circuit. Power converter 10 is electrically connected to motor generator 20 . The motor generator 20 plays a role of an in-vehicle main machine. The power conversion device 10 is also connected to a high voltage battery 40 . The high-voltage battery 40 can employ, for example, a lithium-ion secondary battery, a nickel-metal hydride secondary battery, or the like.

The power conversion system is provided with a V-phase current sensor 46v that detects current flowing through the V-phase of motor generator 20 and a W-phase current sensor 46w that detects current flowing through the W-phase of motor-generator 20 . Furthermore, the power conversion system may be provided with a resolver or the like that detects the rotation angle (electrical angle θ) of the motor generator 20 . Output signals from the various sensors described above are taken into the microcomputer 30 .

The power converter 10 mainly includes a first power element 1 to a sixth power element 6 and a first drive circuit 11 to a sixth drive circuit 16 . Further, the power conversion device 10 includes a smoothing capacitor 7, a first flywheel diode 1d to a sixth flywheel diode 6d, and the like. Power elements 1 to 6 correspond to power switching elements.

Also, each of the first power element 1 to the sixth power element 6 has the same configuration. Each of the first drive circuit 11 to the sixth drive circuit 16 has the same configuration. Therefore, in the following description, the first power element 1 and the first drive circuit 11 may be used as representative examples.

The power conversion circuit 10 includes three series-connected bodies in which two power elements are connected in series. The first is a series connection of a first power element 1 as a U-phase upper arm element and a second power element 2 as a U-phase lower arm element. The second is a series connection of a third power element 3 as a V-phase upper arm element and a fourth power element 4 as a V-phase upper arm element. The third is a series connection of a fifth power element 5 as a W-phase upper arm element and a sixth power element 6 as a W-phase upper arm element. A connection point between each upper arm element and each lower arm element is connected to each phase of motor generator 20 . Thus, each of the first power element 1 to the sixth power element 6 constitutes a power conversion circuit.

In this embodiment, IGBTs are used as examples of the first to sixth power elements 1 to 6 . Each flywheel diode 1d-6d is connected in anti-parallel to each power element 1-6. However, the present disclosure is not limited to this, and MOSFETs, RC-IGBTs, and the like can also be employed.

As shown in FIGS. 1, 2 and 3, each drive circuit 11-16 is individually connected to each corresponding power element 1-6 to drive and control each power element 1-6. there is Further, each drive circuit 11 to 16 is connected to an insulated power supply 50 .

The drive circuits 11-16 have a first terminal T1, a second terminal T2, a third terminal T3, and a fourth terminal T4. An insulated power supply 50 is connected between the first terminal T1 and the second terminal T2 to apply a driving voltage. The third terminal T3 is connected to the gate electrodes of the power elements 1-6. A fourth terminal T4 is connected to the emitter electrode of each of the power elements 1-6. Further, the second terminal T2 is short-circuited to the fourth terminal T4 in the drive circuits 11-16.

Note that the drive circuits 11 to 16 are not particularly limited, and detailed description thereof will be omitted. Also, the first drive circuit 11 is a U-phase upper arm drive circuit. The second drive circuit 12 is a U-phase lower arm drive circuit. The third drive circuit 13 is a V-phase upper arm drive circuit. The fourth drive circuit 14 is a V-phase lower arm drive circuit. The fifth drive circuit 15 is a W-phase upper arm drive circuit. The sixth drive circuit 16 is a W-phase lower arm drive circuit.

As shown in FIG. 1, the microcomputer 30 operates by being powered by a low-voltage battery 44 as a DC power supply. The microcomputer 30 includes a CPU, ROM, RAM, interface circuit, and the like. The low-voltage battery 44 is a battery whose output voltage (eg, 15 V) is lower than the output voltage (eg, several hundred volts) of the high-voltage battery 40 . Here, for example, a lead-acid battery can be used as the low-voltage battery 44 .

Further, the microcomputer 30 receives output signals from the V-phase current sensor 46v and the W-phase current sensor 46w. Also, the output signal of the resolver is input to the microcomputer 30 through the interface circuit. The microcomputer 30 has a control function for controlling the power converter 10 and a conversion function for converting the resolver output signal into a digital absolute position angle signal (electrical angle). The control function can be achieved by the CPU executing a program stored in the ROM and performing predetermined arithmetic processing. The conversion function, on the other hand, can be accomplished by a resolver-to-digital converter.

Also, as shown in FIG. 2, the microcomputer 30 is connected to the insulated power supply 50 and the drive circuit 11 . Specifically, the microcomputer 30 is connected to an insulated power supply 50 and an insulating element 51 . The insulating element 51 is connected to the drive circuit 11 . Therefore, the microcomputer 30 is connected to the driving circuit 11 via the insulating element 51 . A photocoupler or the like can be adopted as the insulating element 51 . The power conversion system is a low voltage system on the side of the microcomputer 30 and a high voltage system on the side of the drive circuit 11 rather than the isolated power supply 50 and the insulating element 51 .

The microcomputer 30 outputs a drive signal 8gxy for the drive circuits 11-16 to drive the power elements 1-6 to the drive circuits 11-16. Further, the microcomputer 30 outputs drive information indicating the drive states of the power elements 1 to 6 to the isolated power supply 50 .

The microcomputer 30 operates the power conversion circuit 10 to control the control amount (torque) of the motor generator 20 to the command torque. Motor-generator 20 is controlled by turning on/off power elements 1 to 6 so that the command current for realizing the command torque and the current flowing through motor-generator 20 match.

The microcomputer 30 generates a drive signal 8gxy (x=U , V, W, y=p, n). However, the present disclosure is not so limited. Note that, for example, the drive signal 8gUp is for the first power element 1 . Further, the driving signal 8gWn is for the sixth power element 6. FIG.

The microcomputer 30 outputs the generated drive signal 8gxy to the drive circuits 11-16 of the power elements 1-6 via the insulating element 51, thereby turning the power elements 1-6 on and off. Specifically, the microcomputer 30 outputs the driving signal 8gxy to each of the driving circuits 11-16 through the insulating element 51. FIG. The isolation element 51 has the function of electrically isolating between the high voltage system and the low voltage system while transmitting signals between these systems.

In this embodiment, the reference potential VstL of the low voltage system and the reference potential VstH of the high voltage system are different. In particular, in the present embodiment, the reference potential VstH of the high voltage system is set to the potential of the negative terminal of the high voltage battery 40, and the reference potential VstL of the low voltage system is the potential of the positive terminal and the potential of the negative terminal of the high voltage battery 40. is set to the vehicle body potential, which is the median value between

Here, the insulated power supply 50 will be described with reference to FIG. The insulated power supply 50 corresponds to a switching power supply section. The insulated power supply 50 supplies driving voltages to the driving circuits 11 to 16 and the like. In addition, insulated power supply 50 changes the operation state of insulated power supply 50 so as to correspond to the drive state of power elements 1-6 based on the drive information indicating the drive state of power elements 1-6.

The isolated power supply 50 includes a plurality of transformers, a plurality of diodes, a plurality of capacitors, a power supply side switching element 100, a power supply IC 101, a feedback circuit 102, and the like. The insulated power supply 50 is a flyback switching power supply.

The insulated power supply 50 includes a first transformer 80, a second transformer 82, a third transformer 84, a fourth transformer 86, and a fifth transformer 88 as a plurality of transformers. The insulated power supply 50 also includes a first diode 90a, a second diode 92a, a third diode 94a, a fourth diode 96a, and a fifth diode 98a as a plurality of diodes. The insulated power supply 50 includes a first capacitor 90b, a second capacitor 92b, a third capacitor 94b, a fourth capacitor 96b, and a fifth capacitor 98b as a plurality of capacitors. In this embodiment, electrolytic capacitors are used as the first to fifth capacitors.

Hereinafter, when a plurality of elements are collectively described, reference numerals may be omitted. For example, when the first to fifth transformers 80, 82, 84, 86 and 88 are collectively described, they are described as first to fifth transformers. When collectively describing the first to fifth diodes 90a, 92a, 94a, 96a, and 98a, they are referred to as first to fifth diodes. When collectively describing the first to fifth capacitors 90b, 92b, 94b, 96b, and 98b, they are referred to as first to fifth capacitors. The same applies to first to fifth primary coils 80a, 82a, 84a, 86a, 88a and first to fifth secondary coils 80b, 82b, 84b, 86b, 88b, which will be described later.

The power supply side switching element 100 employs an N-channel MOSFET. The power supply side switching element 100 is abbreviated as the power supply side switch 100 hereinafter.

Here, the isolated power supply 50 will be described in detail. The positive terminal of the low-voltage battery 44 is connected to the negative terminal of the low-voltage battery 44 through a parallel connection of the first to fifth primary coils constituting the first to fifth transformers and the power supply side switch 100. It is connected. That is, the power-side switch 100 is turned on to form a closed circuit including the low-voltage battery 44, the parallel connection of the first to fifth primary coils, and the power-side switch 100. It is configured. A capacitor 104 is connected in parallel with the low voltage battery 44 .

A first secondary coil 80b that constitutes the first transformer 80 is connected to the U-phase upper arm drive circuit 11 via a first diode 90a and a first capacitor 90b. Specifically, the connection point between the first diode 90a and the first capacitor 90b is connected to the first terminal T1 of the U-phase upper arm drive circuit 11, and the connection point between the first capacitor 90b and the first secondary coil 80b. is connected to the second terminal T2. In FIG. 3, the first terminal T1 and the second terminal T2 included in the drive circuits 11 to 16 are illustrated for the U-phase upper arm drive circuit 11 as a representative.

A second secondary coil 82b that constitutes the second transformer 82 is connected to the V-phase upper arm drive circuit 13 via a second diode 92a and a second capacitor 92b. A third secondary coil 84b forming the third transformer 84 is connected to the W-phase upper arm drive circuit 15 via a third diode 94a and a third capacitor 94b. Thus, the second secondary coil 82b and the third secondary coil 84b have the same connection configuration as the first secondary coil 80b.

A fourth secondary coil 86b forming the fourth transformer 86 is connected to each of the lower arm drive circuits 12, 14, 16 via a fourth diode 96a and a fourth capacitor 96b. Furthermore, the fourth transformer 86 has a feedback coil 86c.

In this embodiment, the number of turns of the first to fourth primary coils is set to be the same. The number of turns of the first to fourth secondary coils and the number of turns of the feedback coil 86c are set to be the same. This setting aims to make the output voltage of the feedback coil 86c and the output voltage of the first to fourth secondary coils the same. However, the present disclosure is not so limited.

The feedback coil 86c is connected to the power supply IC 101 via the feedback circuit 102. FIG. The feedback circuit 102 comprises a sensing diode 102a, a sensing capacitor 102b, a first resistor 102c and a second resistor 102d. The output voltage of the feedback coil 86c is divided by the first resistor 102c and the second resistor 102d after passing through the detection diode 102a. A voltage divided by the first resistor 102c and the second resistor 102d is input to the power supply IC 101 via the detection terminal Tfb of the power supply IC 101 . Hereinafter, the divided voltage is also referred to as feedback voltage Vfb. The feedback coil 86c and the feedback circuit 102 can also be said to be a voltage detection section.

A fifth secondary coil 88b that constitutes the fifth transformer 88 is connected to a resolver excitation circuit (not shown) via a fifth diode 98a and a fifth capacitor 98b. For example, the connection point between the fifth diode 98a and the fifth capacitor 98b is connected to the fifth terminal T5, which is the positive power supply input terminal of the excitation operational amplifier that constitutes the excitation circuit. On the other hand, the connection point between the fifth capacitor 98b and the fifth secondary coil 88b is connected (that is, grounded) to the negative power supply input terminal of the excitation operational amplifier.

Note that the resolver and the excitation circuit can be applied with reference to Japanese Unexamined Patent Application Publication No. 2015-73407. Vrm in FIG. 3 is a drive voltage for the excitation circuit. On the other hand, Von is a driving voltage for the power elements 1-6. The driving voltage Vrm is set higher than the driving voltage Vom.

The power supply IC 101 is configured by an integrated circuit. The power supply IC 101 is connected to the gate electrode of the power supply side switch 100 . The power supply IC 101 turns on/off the power supply side switch 100 in order to feedback-control the feedback voltage Vfb to the target voltage Vtgt. Also, the power supply IC 101 has the detection terminal Tfb connected to the wiring between the first resistor 102c and the second resistor 102d.

The target voltage Vtgt is set so that the output voltage of the fourth secondary coil 86b becomes the drive voltage Vom of the power elements 1-6. Specifically, the target voltage Vtgt is set to a value obtained by dividing the driving voltage Vom by the first and second resistors 102c and 102d.

Further, the isolated power supply 50 changes its operating state so as to correspond to the driving state of the power elements 1-6 based on the driving information indicating the driving state of the power elements 1-6. The isolated power supply 50 changes the switching frequency or voltage of the power supply side switch 100 as an operating state. The drive state may be an individual drive state for the power elements 1-6 or a common drive state for the power elements 1-6.

In this embodiment, the switching frequency of the power supply side switch 100 is used as an example of the operating state of the insulated power supply 50 to be changed. Further, in this embodiment, the driving frequencies of the power elements 1 to 6 are used as an example of the driving state. Therefore, in the present embodiment, information indicating the driving frequencies of the power elements 1-6 is used as an example of the driving information indicating the driving states of the power elements 1-6. For example, information indicating that the driving frequency is high and information indicating that the driving frequency is low can be used as the information indicating the driving frequency.

Therefore, the insulated power supply 50 changes the switching frequency of the power supply side switch 100 so as to correspond to the drive frequencies of the power elements 1-6 based on the information indicating the drive frequencies of the power elements 1-6.

For example, the microcomputer 30 transmits information indicating the drive frequencies of the power elements 1 to 6 to the isolated power supply 50 . The insulated power supply 50 (power supply IC 101) determines the loads of the drive circuits 11-16 and the power elements 1-6 based on the information indicating the drive frequency. The power supply IC 101 increases the switching frequency of the power supply side switch 100 as the load increases. That is, the power supply IC 101 makes the switching frequency of the power supply side switch 100 higher when the load is large than when the load is small. In other words, the power supply IC 101 lowers the switching frequency of the power supply side switch 100 when the load is small than when the load is large. It should be noted that the present disclosure may determine only the loads of power elements 1-6.

Furthermore, the power supply IC 101 considers that the higher the driving frequency of the power elements 1 to 6, the larger the load. Therefore, as shown in FIG. 4, the power supply IC 101 increases the switching frequency of the power supply side switch 100 as the drive frequency of the power elements 1 to 6 increases. That is, the power supply IC 101 makes the switching frequency of the power supply side switch 100 higher when the driving frequency of the power elements 1-6 is high than when the driving frequency of the power elements 1-6 is low. In other words, the power supply IC 101 lowers the switching frequency of the power supply side switch 100 when the driving frequency of the power elements 1-6 is low than when the driving frequency of the power elements 1-6 is high. As a result, the power conversion system can reduce current consumption in addition to driving loss, which will be described later.

Here, the operation of the power conversion system will be described. The insulated power supply 50 generates power on the high voltage side. The microcomputer 30 transmits information indicating the driving frequencies of the power elements 1 to 6 to the insulated power supply 50 . The isolated power supply 50 changes the switching frequency of the power-side switch 100 based on the received drive frequency, as described above.

The microcomputer 30 outputs a drive signal 8gxy to the drive circuits 11-16 based on the drive request from the outside. The drive signal 8gxy is converted from a low voltage signal to a high voltage signal by the insulating element 51 . The drive circuits 11-16 turn on/off the power elements 1-6 according to the drive signal 8gxy.

The power conversion system continuously performs from the generation of the power supply on the high voltage side to the on/off operation of the power elements 1-6. The power conversion system performs operations from generation of a high-voltage side power supply to turning on/off the power elements 1 to 6. FIG. Thereafter, the power conversion system may continuously perform from the output of the drive signal 8gxy to the on/off operation of the power elements 1-6.

Here, the effect of the power conversion system will be described. The load of the isolated power supply 50 depends on the driving state of the power elements 1-6 of the power conversion circuit. Therefore, since the power conversion system is configured as described above, the operating state of the isolated power supply 50 can correspond to the driving state of the power elements 1-6. Therefore, the power conversion system can reduce switching loss in the isolated power supply 50 without increasing the number of power elements.

More specifically, in the power conversion system, when the driving frequency of the power elements 1-6 is high, the required currents of the driving circuits 11-16 change quickly. In the power conversion system, the switching frequency of the power supply side switch 100 in the insulated power supply 50 that supplies the current must be correspondingly increased to cope with rapid changes. On the other hand, in the power conversion system, when the driving frequency of the power elements 1-6 is low, the change in the required current of the driving circuits 11-16 is slow, and the switching frequency of the power supply side switch 100 can be lowered. Therefore, the power conversion system can reduce the switching loss of the isolated power supply 50 while supplying power necessary for driving.

Note that the power conversion system may change the operating state of the insulated power supply 100 according to the temperature. That is, the power supply IC 101 acquires the temperature of the power converter 10 as an example of drive information. Then, the power supply IC 101 considers that the higher the temperature, the larger the load. Therefore, the power supply IC 101 increases the switching frequency of the power supply side switch 100 as the load increases. Even if it does in this way, there can exist an effect similar to the above.

The preferred embodiments of the present disclosure have been described above. However, the present disclosure is by no means limited to the above embodiments, and various modifications are possible without departing from the scope of the present disclosure.

Modifications 1 to 14 will be described below as other forms of the present disclosure. The above-described embodiment and Modifications 1 to 14 can be implemented independently, but can also be implemented in combination as appropriate. The present disclosure can be implemented in various combinations without being limited to the combinations shown in the embodiments. For example, the driving information and the operating state to be changed that are used in the modified examples below can also be used in the above-described embodiment and other modified examples.

(Modification 1)
Based on FIG. 5, the power conversion system of Modification 1 will be described. Modification 1 will mainly be described with respect to points different from the above-described embodiment. Modification 1 differs from the embodiment in drive information, which is information for changing the operating state of the insulated power supply 50 . The configuration and basic operation of the power conversion system of Modification 1 are the same as those of the embodiment.

The power conversion system has a configuration in which the driving modes of the power elements 1 to 6 are switched. The power conversion system switches between a normal drive mode in which the drive signal is a sine wave and a rectangular wave drive mode in which the drive signal is a rectangular wave. The microcomputer 30 switches the drive mode according to predetermined conditions. In FIG. 5, the upper stage shows the normal drive mode, and the lower stage shows the rectangular wave drive mode.

The microcomputer 30 transmits the drive modes of the power elements 1 to 6 as drive information. Then, the power supply IC 101 of the isolated power supply 50 acquires the drive modes of the power elements 1-6. Also, the power supply IC 101 changes its operating state based on the drive mode. That is, the power supply IC 101 considers that the load increases as the drive frequency increases, and increases the switching frequency of the power supply side switch 100 .

Specifically, a square wave appears to have a lower driving frequency than a sine wave. Also, as described above, the power supply IC 101 assumes that the higher the drive frequency of the power elements 1 to 6, the greater the load. When the drive frequency of the power elements 1-6 is high, the power supply IC 101 makes the switching frequency of the power-side switch 100 higher than when the drive frequency of the power elements 1-6 is low. Therefore, as shown in FIG. 5, the power supply IC 101 makes the switching frequency of the power supply side switch 100 lower when the drive mode is the rectangular wave drive mode than when the drive mode is the normal drive mode.

The power conversion system of Modification 1 can produce effects similar to those of the above-described embodiment. Furthermore, the power conversion system of Modification 1 can reduce current consumption.

(Modification 2)
Based on FIG. 6, the power conversion system of Modification 2 will be described. Modification 2 will mainly be described with respect to points different from the above-described embodiment. Modification 2 differs from the embodiment in drive information, which is information for changing the operating state of the insulated power supply 50 . The configuration and basic operation of the power conversion system of Modification 2 are the same as those of the embodiment.

The power conversion system has a configuration in which the driving modes of the power elements 1 to 6 are switched. The power conversion system switches between a normal drive mode in which the drive signal is a sine wave and an overmodulation drive mode in which the drive signal is overmodulated. The microcomputer 30 switches the drive mode according to predetermined conditions. In FIG. 6, the upper stage shows the normal drive mode, and the lower stage shows the overmodulation drive mode.

The microcomputer 30 transmits the drive modes of the power elements 1 to 6 as drive information. Then, the power supply IC 101 of the isolated power supply 50 acquires the drive modes of the power elements 1-6. Also, the power supply IC 101 changes its operating state based on the drive mode. That is, the power supply IC 101 considers that the load increases as the drive frequency increases, and increases the switching frequency of the power supply side switch 100 .

Specifically, in the case of overmodulation, the drive frequency appears lower than in the sine wave. Also, as described above, the power supply IC 101 assumes that the higher the drive frequency of the power elements 1 to 6, the greater the load. When the drive frequency of the power elements 1-6 is high, the power supply IC 101 makes the switching frequency of the power-side switch 100 higher than when the drive frequency of the power elements 1-6 is low. Therefore, as shown in FIG. 6, when the drive mode is the overmodulation drive mode, the power supply IC 101 lowers the switching frequency of the power supply side switch 100 than when the drive mode is the normal drive mode.

The power conversion system of Modification 2 can achieve the same effects as those of the above embodiment. Furthermore, the power conversion system of Modification 2 can reduce current consumption.

Modification 2 can also be implemented in combination with Modification 1. That is, the microcomputer 30 is configured to be able to switch between three drive modes: normal drive mode, rectangular wave drive mode, and overmodulation drive mode. Then, the power supply IC 101 changes its operating state based on the drive mode. In this case, the power supply IC 101 lowers the switching frequency of the power supply side switch 100 in the order of normal drive mode, overmodulation drive mode, and rectangular wave drive mode.

(Modification 3)
Based on FIG. 7, the power conversion system of Modification 3 will be described. Modification 3 will mainly be described with respect to points different from the above-described embodiment. Modification 3 differs from the embodiment in drive information, which is information for changing the operating state of the insulated power supply 50 . The configuration and basic operation of the power conversion system of Modification 3 are the same as those of the embodiment.

In this modified example, the value of current flowing through each of the power elements 1 to 6 is used as drive information. For this reason, the power conversion system includes a current detector that detects the current flowing through each of the power elements 1-6. A well-known technique can be adopted for the current detection unit. A method for detecting the current flowing through each of the power elements 1 to 6 is not particularly limited. In FIG. 7, the upper stage shows the operation when the power device current is larger than the lower stage.

The microcomputer 30 transmits the current values of the power elements 1 to 6 as drive information. Then, the power supply IC 101 of the isolated power supply 50 obtains the current values of the power elements 1-6. Also, the power supply IC 101 changes the operating state based on the current value.

The power supply IC 101 considers that the load increases as the current value increases because the gate total charge increases. Therefore, as shown in FIG. 7, the power supply IC 101 increases the switching frequency of the power supply side switch 100 as the current value increases.

In other words, the power supply IC 101 considers that the smaller the current value, the smaller the total gate charge amount, and thus the smaller the load. Therefore, the power supply IC 101 lowers the switching frequency of the power supply side switch 100 as the current value is smaller.

The power conversion system of Modification 3 can achieve the same effects as those of the above embodiment. Furthermore, the power conversion system of Modification 3 can reduce the switching loss in the isolated power supply 50 according to the currents of the power elements 1-6. The power conversion system of modification 3 can reduce current consumption.

(Modification 4)
Based on FIG. 8, the power conversion system of Modification 4 will be described. Modification 4 will mainly be described with respect to points different from Modification 3 described above. Modification 4 differs from Modification 3 in the region where the operating state of the insulated power supply 50 is changed. The configuration and operation of the power conversion system of Modification 4 are the same as those of the above embodiment.

The microcomputer 30 transmits the current values of the power elements 1 to 6 as drive information. Then, the power supply IC 101 of the isolated power supply 50 obtains the current values of the power elements 1-6. Also, the power supply IC 101 changes its operating state based on the current value. In particular, as shown in the lower part of FIG. 8, the power supply IC 101 changes the operating state based on the current value only when the current value of each of the power elements 1 to 6 is greater than a predetermined value in a large current region. The power supply IC 101 considers that the load increases as the current value increases because the gate total charge amount increases. Therefore, the power supply IC 101 increases the switching frequency of the power supply side switch 100 as the current value increases. In addition, in FIG. 8, the large current region is surrounded by a dotted line circle.

The power conversion system of Modification 4 can achieve the same effects as Modification 3 described above.

(Modification 5)
Based on FIG. 9, the power conversion system of Modification 5 will be described. Modification 5 will mainly be described with respect to points different from the above-described embodiment. Modification 5 differs from the embodiment in drive information, which is information for changing the operating state of the insulated power supply 50 . The configuration and basic operation of the power conversion system of Modification 5 are the same as those of the embodiment.

In this modified example, voltage values applied to the power elements 1 to 6 are used as drive information. For this reason, the power conversion system includes a voltage detection section that detects the voltage applied to each of the power elements 1-6. The voltage detector detects the collector-emitter voltage of each of the power elements 1-6. A well-known technique can be adopted for the voltage detection unit. A method of detecting the voltage applied to each of the power elements 1 to 6 is not particularly limited. In FIG. 9, the upper stage shows the operation when the power element voltage is lower than the lower stage.

The microcomputer 30 transmits voltage values of the power elements 1 to 6 as drive information. Then, the power supply IC 101 of the isolated power supply 50 obtains the voltage values of the power elements 1-6. Also, the power supply IC 101 changes the operating state based on the voltage value.

The power supply IC 101 assumes that the lower the voltage value, the greater the total gate charge amount, and thus the greater the load. Therefore, as shown in FIG. 9, the power supply IC 101 increases the switching frequency of the power supply side switch 100 as the voltage value decreases.

In other words, the power supply IC 101 considers that the higher the voltage value, the smaller the total gate charge amount, and hence the smaller the load. Therefore, the power supply IC 101 lowers the switching frequency of the power supply side switch 100 as the voltage value increases.

The power conversion system of Modification 5 can achieve the same effects as those of the above embodiment. Furthermore, the power conversion system of Modification 5 can reduce the switching loss in the isolated power supply 50 according to the voltages of the power elements 1-6. The power conversion system of modification 3 can reduce current consumption.

It should be noted that the present disclosure can also employ MOSFETs as each of the power elements 1-6. In this case, the voltage detector detects the drain-source voltage of each of the power elements 1-6.

(Modification 6)
Based on FIG. 10, the power conversion system of Modification 6 will be described. Modification 6 will mainly be described with respect to points different from Modification 5 above. Modification 6 differs from Modification 5 in drive information, which is information for changing the operating state of the insulated power supply 50 . The configuration and basic operation of the power conversion system of Modification 6 are the same as those of Modification 5.

In this modified example, gate voltage values applied to the power elements 1 to 6 are used as drive information. Therefore, the power conversion system includes a voltage detection section that detects the gate voltage applied to each of the power elements 1-6. A well-known technique can be adopted for the voltage detection unit. A method for detecting the gate voltage applied to each of the power elements 1 to 6 is not particularly limited. In FIG. 10, the upper stage shows the operation when the gate voltage is higher than the lower stage.

The microcomputer 30 transmits the gate voltage values of the power elements 1 to 6 as drive information. Then, the power supply IC 101 of the isolated power supply 50 obtains the gate voltage values of the power elements 1-6. Also, the power supply IC 101 changes the operating state based on the gate voltage value.

The power supply IC 101 assumes that the load increases because the gate total charge amount increases as the gate voltage value increases. Therefore, as shown in FIG. 10, the power supply IC 101 increases the switching frequency of the power supply side switch 100 as the gate voltage value increases.

In other words, the power supply IC 101 considers that the smaller the gate voltage value, the smaller the gate total charge amount, and thus the smaller the load. Therefore, the power supply IC 101 lowers the switching frequency of the power supply side switch 100 as the gate voltage value is smaller.

The power conversion system of Modification 6 can achieve the same effects as Modification 5.

(Modification 7)
The power conversion system of Modification 7 will be described with reference to FIGS. 11 and 12. FIG. Modification 7 will mainly be described with respect to points different from the above-described embodiment. Modification 7 differs from the embodiment in the operating state of the insulated power supply 50 to be changed. Moreover, the modification 7 differs from the embodiment in the feedback circuit 102 . The basic configuration and operation of the power conversion system of Modification 7 are the same as those of the embodiment.

The insulated power supply 50 changes its operating state so as to correspond to the driving state of the power elements 1-6 based on the driving information indicating the driving state of the power elements 1-6, as in the above embodiment. However, the insulated power supply 50 of this modified example changes the voltage of the insulated power supply 50 as an operating state. The voltage of the insulated power supply 50 is a driving voltage applied to the driving circuits 11-16. In other words, this modification changes the output of the insulated power supply 50 as the operating state. In FIG. 11, the upper stage shows the operation when the drive frequency of the power elements 1 to 6 is higher than the lower stage.

As shown in FIG. 12, the feedback circuit 102 of this modification includes a voltage dividing resistor 102e and a voltage dividing switching element 102f. Hereinafter, the voltage dividing switching element 102f is abbreviated as a voltage dividing switch 102f. The microcomputer 30 is connected to the gate of the voltage dividing switch 102f.

The driving voltage can be changed, for example, by switching the feedback constant by the microcomputer 30 . When increasing the driving voltage of the insulated power supply 50, the microcomputer 30 turns on the voltage dividing switch 102f to change the ratio of the voltage dividing resistors.

As a result, the feedback circuit 102 has a smaller resistance value due to the parallel resistance of the voltage dividing resistor 102e and the second resistor 102d, and the feedback constant becomes smaller. Therefore, the power supply IC 101 increases the driving voltage (output). Conversely, when lowering the driving voltage of the insulated power supply 50, the microcomputer 30 turns off the voltage dividing switch 102f.

However, the present disclosure is not limited to this. In the present disclosure, the microcomputer 30 may directly instruct the power supply IC 101 to change the driving voltage.

By the way, it is more efficient to use a large amount of power supply than to use a small amount with respect to the supplied power (voltage). This modification uses this principle to improve efficiency.

Therefore, as shown in FIG. 11, the power supply IC 101 increases the drive voltage of the insulated power supply 50 as the drive frequency of the power elements 1 to 6 increases. That is, the power supply IC 101 makes the driving voltage higher when the driving frequency of the power elements 1-6 is high than when the driving frequency of the power elements 1-6 is low. In other words, the power supply IC 101 lowers the driving voltage when the driving frequency of the power elements 1-6 is low than when the driving frequency of the power elements 1-6 is high. It can also be said that the power supply IC 101 increases the output of the isolated power supply 50 as the driving frequency of the power elements 1-6 increases, and decreases the output of the isolated power supply 50 as the driving frequency of the power elements 1-6 decreases. It can also be said that the power conversion system operates the isolated power supply 50 at a point where the efficiency of the isolated power supply 50 is improved by varying the driving voltage.

The power conversion system of Modification 7 can achieve the same effects as those of the above embodiment. Furthermore, since the power conversion system of Modified Example 7 can increase the efficiency of the isolated power supply 50, the switching loss in the isolated power supply 50 can be reduced.

This modified example can also be applied to the embodiment and modified examples 1 to 6. That is, in the embodiment and Modifications 1 to 6, the driving voltage of the insulated power supply 50 may be changed as the operating state of the insulated power supply 50 . In this case, in the embodiment and Modifications 1 to 6, the driving voltage is set higher when the load is large than when the load is small. That is, in the embodiment and Modifications 1 to 6, the higher the load, the higher the driving voltage. Also, in other modified examples, instead of the switching frequency of the power supply side switch 100, the driving voltage of the insulated power supply 50 may be changed.

(Modification 8)
The power conversion system of Modification 8 will be described based on FIGS. 13 and 14. FIG. Modification 1 will mainly be described with respect to points different from the above-described embodiment. Modification 1 differs from the embodiment in the change timing of the operating state of the insulated power supply 50 . The configuration and basic operation of the power conversion system of Modification 8 are the same as those of the embodiment.

As shown in FIG. 13, the insulated power supply 50 changes the state of the load when the load changes from a large state to a small state, that is, when the drive frequency of the power elements 1 to 6 changes from a high state to a low state. Later, the operating state of the isolated power supply 50 is changed. In other words, when the load changes from a large state to a small state at timing tm1, the insulating power supply 50 changes its operating state at timing tm2 after timing tm1. This modified example adopts an example in which the switching frequency of the power-side switch 100 is lowered at the timing tm2.

In this case, the microcomputer 30 transmits drive information to the insulated power supply 50 with a time lag. In other words, the microcomputer 30 delays the timing at which the drive states of the power elements 1 to 6 change by a predetermined time, and transmits the changed drive information. This allows the power conversion system to change the operating state of the isolated power supply 50 after a load state change.

On the other hand, as shown in FIG. 14, the insulated power supply 50 changes from a low load state to a high load state, that is, when the drive frequency of the power elements 1 to 6 changes from a low state to a high state. Before the change, it changes the operating state of the isolated power supply 50 . In other words, when the load changes from light to heavy at timing tm12, the insulating power supply 50 changes its operating state at timing tm11 prior to timing tm12. This modified example adopts an example in which the switching frequency of the power-side switch 100 is increased at timing tm11.

In this case, the microcomputer 30 transmits drive information to the insulated power supply 50 with a time lag. That is, the microcomputer 30 advances the timing of changing the driving state of the power elements 1 to 6 by a predetermined time and transmits the changed driving information. This allows the power conversion system to change the operating state of the isolated power supply 50 prior to the load state change.

The power conversion system of Modification 8 can achieve the same effects as those of the above embodiment. Furthermore, the power supply side switch 100 has higher controllability and resistance to fluctuations when the switching frequency is higher than when the switching frequency is low. Therefore, the power conversion system of Modification 8 can suppress the power fluctuation of the insulated power supply 50 .

Note that the timing of changing the operating state of the insulated power supply 50 in the present disclosure is not limited to the above. The present disclosure may change the operating state of the isolated power supply 50 concurrently with the load state change when the load changes from a heavy state to a light state. Also, the present disclosure may change the operating state of the isolated power supply 50 at the same time as the state of the load changes when the load changes from a light state to a heavy state.

Further, the present disclosure changes the operating state of the isolated power supply 50 after a load state change when the load changes from a large to a small state, and changes the load state change when the load changes from a small to a large state. At the same time, the operating state of the insulated power supply 50 may be changed. Conversely, the present disclosure changes the operating state of the isolated power supply 50 before the state change of the load when the load changes from light to heavy, and changes the operating state of the isolated power supply 50 when the load changes from heavy to light. The operating state of the isolated power supply 50 may be changed simultaneously with the state change.

Further, the power conversion system of Modification 8 can also be applied when the driving voltage is changed as the operating state of the insulated power supply 50 .

(Modification 9)
The power conversion system of Modification 9 will be described based on FIGS. 15, 16, and 17. FIG. Modification 9 will mainly be described with respect to points different from the above-described embodiment. The ninth modification differs from the embodiment in drive information, which is information for changing the operating state of the insulated power supply 50 . The basic operation of the power conversion system of Modification 9 is the same as that of the embodiment.

As shown in FIG. 15, two isolation elements 52, 53 are provided. The insulating elements 52 and 53 can employ elements similar to the insulating element 51 . The microcomputer 30 outputs the generated drive signal 8gxy to the drive circuit 11 of the power element 1 through the first insulating element 52 as in the embodiment. On the other hand, the driving circuit 11 outputs a signal to the microcomputer 30 via the second insulating element 53 .

The drive circuit 11 detects an abnormality in the power element 1 driven by itself. Then, the drive circuit 11 outputs an abnormality detection signal indicating the detection result to the microcomputer 30 via the second insulating element 53 . A method for detecting an abnormality in the power element 1 is not particularly limited. The anomaly detection signal corresponds to an anomaly detection result. The other drive circuits 12-16 similarly detect an abnormality in the power devices 2-6 driven by themselves and output an abnormality detection signal to the microcomputer 30. FIG.

Therefore, the microcomputer 30 receives an abnormality detection signal indicating the abnormality detection result of the power element 1 . Therefore, the microcomputer 30 can individually determine whether or not the power device 1 is abnormal.

Upon receiving the abnormality detection signal, the microcomputer 30 transmits the abnormality detection signal to the insulated power supply 50 as drive information. Further, when the abnormality detection signal indicates an abnormality, the microcomputer 30 stops the abnormal drive circuit. The microcomputer 30 stops the first drive circuit 11, for example, when the abnormality detection signal, which is the detection result of the power element 1, indicates an abnormality. However, the microcomputer 30 may stop all the driving circuits 11 to 16 when even one of the plurality of abnormality detection signals indicates an abnormality.

The insulated power supply 50 changes its operating state based on the abnormality detection signal. Specifically, as shown in FIG. 16, when the abnormality detection signal indicates an abnormality, the power supply IC 101 lowers the switching frequency of the power supply side switch 100 than when it does not indicate an abnormality.

The power conversion system of Modification 9 can achieve the same effects as those of the above embodiment. Furthermore, the power conversion system of Modification 9 can reduce current consumption.

Note that the power conversion system may be configured as shown in FIG. 17 . That is, as shown in the upper part of FIG. 17 , the drive circuit 11 may output the abnormality detection signal to the isolated power supply 50 via the second insulating element 52 without via the microcomputer 30 . Further, as shown in the lower part of FIG. 17 , the drive circuit 11 may output the abnormality detection signal to the isolated power supply 50 without going through the microcomputer 30 or the second insulating element 52 .

In this case, the drive circuit 11 detects an abnormality of the power element 1 by itself, and stops the power element 1 when it determines that there is an abnormality. The power supply IC 101 changes its operating state based on the abnormality detection signal received by itself, regardless of the signal from the microcomputer 30 . As a result, the power conversion system can stop the power element 1 more quickly than when the microcomputer 30 stops the power element 1 via the drive circuit 11 . Moreover, the power conversion system can change the operating state more quickly than when the microcomputer 30 transmits the abnormality detection signal.

(Modification 10)
The power conversion system of Modification 10 will be described with reference to FIGS. 18 and 19. FIG. Modification 10 will mainly be described with respect to points different from the above embodiment. Modification 10 differs from the embodiment in circuit configuration. The basic operation of the power conversion system of Modification 10 is the same as that of the embodiment.

As shown in FIG. 18, the power conversion system includes an inverter circuit 10a, a generator circuit 10b, and a booster circuit 10c as a plurality of switch groups. That is, each of the inverter circuit 10a, generator circuit 10b, and booster circuit 10c includes at least one power element n. n is a natural number of 2 or more.

Specifically, the inverter circuit 10a includes six power elements n. The generator circuit 10b comprises six power elements n. The booster circuit 10c has two power elements n. A drive circuit 1n is individually connected to each power element n.

Each of the inverter circuit 10a, the generator circuit 10b, and the booster circuit 10c includes an insulated power supply 50n and an insulating element 5n. That is, the insulated power supply 50n and the insulating element 5n are separated for each of the inverter circuit 10a, the generator circuit 10b, and the booster circuit 10c.

The microcomputer 30 is commonly connected to each insulating power supply 50n and each insulating element 5n. That is, only one microcomputer 30 is provided for the plurality of isolated power supplies 50n and the plurality of insulating elements 5n. The microcomputer 30 is configured to be able to individually transmit drive information to each of the isolated power supplies 50n.

Thereby, the power conversion system can control the isolated power supply 50n in accordance with the driving information of the power elements n included in the inverter circuit 10a, the generator circuit 10b, and the booster circuit 10c. Therefore, each insulated power supply 50n is configured to be able to change its operating state individually without changing the operating state at the same time.

In addition, the power conversion system can intentionally shift the timing of changing the operating state. As for the interval for shifting the change timing, for example, a period in which input fluctuations are contained is obtained in advance including variations and stored in the memory of the microcomputer 30 . Then, the microcomputer 30 refers to the stored contents of the memory and adjusts the transmission timing of the drive information, thereby shifting the timing of changing the operating state. Furthermore, the microcomputer 30 may learn and update input fluctuations.

As shown in FIG. 19, for example, the booster circuit 10c changes the operating state of the isolated power supply 50n at timing tm31. The generator circuit 10b changes the operating state of the isolated power supply 50n at timing tm32 after timing tm31. The inverter circuit 10a changes the operating state of the insulated power supply 50n at timing tm33 after timing tm32.

The power conversion system of this modified example can achieve the same effects as those of the above-described embodiment.

(Modification 11)
The power conversion system of Modification 11 will be described with reference to FIG. 20 . In the eleventh modification, mainly the differences from the tenth modification will be described. Modification 11 differs from Modification 10 in circuit configuration. The basic operation of the power conversion system of Modification 11 is the same as that of the embodiment. Note that FIG. 20 shows only the isolated power supply 50n and the insulating element 5n corresponding to one arm. That is, in FIG. 20, illustration of the insulated power supply 50n and the insulating element 5n corresponding to the remaining two arms is omitted.

The power conversion system has a plurality of arms each including one power element n. Here, as an example, an example with three arms including two power elements n is adopted. Each arm corresponds to the U-phase, V-phase, and W-phase of the three-phase inverter. Each arm can also be said to be a switch group.

Further, the power conversion system has multiple isolated power supplies 50n and multiple isolation elements 5n. Each insulating power supply 50n and each insulating element 5n are provided correspondingly for each arm. Thus, the power conversion system has three isolated power supplies 50n and three isolation elements 5n. Each insulated power supply 50n acquires the drive information of the corresponding arm and changes the operating state based on the drive information.

The power conversion system of this modified example can achieve the same effects as those of the eleventh modified example.

(Modification 12)
The power conversion system of Modification 11 will be described with reference to FIG. 21 . Modification 11 will mainly be described with respect to points different from the above-described embodiment. Modification 11 differs from the embodiment in circuit configuration. The basic operation of the power conversion system of Modification 11 is the same as that of the embodiment.

In this modified example, the switching frequency of the power supply side switch 100 is used as an example of the operating state of the insulated power supply 50 to be changed. Further, in this modified example, the drive frequencies of the power elements 1 to 6 are used as an example of the drive state. Therefore, in this modified example, information indicating the driving frequencies of the power elements 1-6 is used as an example of the driving information indicating the driving states of the power elements 1-6.

As shown in FIG. 21, the power conversion system is configured such that the driving frequencies of power elements 1 to 6 can be changed stepwise. Therefore, the microcomputer 30 transmits information indicating the drive frequency for each stage of the power elements 1 to 6 to the insulated power supply 50 .

At this time, the microcomputer 30 transmits information indicating the drive frequency corresponding to each stage, as shown in the upper part of FIG. However, the present disclosure is not so limited. The microcomputer 30 may transmit, as drive information, information indicating drive frequencies in some of the drive frequencies in a plurality of steps. The microcomputer 30 may transmit only the information indicating the highest driving frequency and the information indicating the lowest driving frequency as drive information, as shown in the lower part of FIG. 21, for example.

The insulated power supply 50 (power supply IC 101) determines the loads of the drive circuits 11-16 and the power elements 1-6 based on the information indicating the drive frequency, as in the embodiment. The power supply IC 101 increases the switching frequency of the power supply side switch 100 as the load increases. At this time, the power supply IC 101 changes the switching frequency of the power supply side switch 100 step by step based on the information indicating the driving frequency of each step. In the case of the upper part of FIG. 21, the power supply IC 101 is changed stepwise at timings tm41 and tm42. In the case of the lower part of FIG. 21, the power supply IC 101 is changed stepwise at timings tm51 and tm52.

The power conversion system of this modified example can achieve the same effects as those of the embodiment. Furthermore, the power conversion system of this modification can reduce the switching loss of the insulated power supply 50 while suppressing power supply fluctuations.

DESCRIPTION OF SYMBOLS 10... Power converter, 1-n... Power switching element, 1d-6d... Flywheel diode, 11-1n... Drive circuit, 20... Motor generator, 30... Microcomputer, 40... High-voltage battery, 50... Insulated power supply, 51 100 Power supply side switching element 101 Power supply IC 104 Capacitor

Claims (13)

at least one power switching element (1 to n) constituting a power conversion circuit;
at least one drive circuit (11 to 1n) for driving the power switching element;
at least one switching power supply unit (50) for supplying power to the driving circuit;
a microcomputer (30) that outputs a drive signal for the drive circuit to drive the power switching element to the drive circuit,
The switching power supply unit changes its own operation state so as to correspond to the drive state of the power switching element based on drive information indicating the drive state of the power switching element ,
The switching power supply unit changes the switching frequency as the operating state, determines the load of the power switching element based on the drive information, and increases the switching frequency as the load increases. system. The switching power supply unit acquires the driving frequency of the power switching element as the driving information, and changes the operating state based on the driving frequency. It is assumed that the higher the driving frequency, the larger the load. The power conversion system according to claim 1 , wherein the switching frequency is increased. The switching power supply unit acquires the drive mode of the power switching element as the drive information, and changes the operating state based on the drive mode. 2. The power conversion system according to claim 1 , wherein the switching frequency is increased. A current detection unit that detects a current flowing through the power switching element,
The switching power supply unit acquires the current value detected by the current detection unit as the drive information, and changes the operating state based on the current value. The larger the current value, the larger the load. 2. The power conversion system according to claim 1 , wherein the switching frequency is increased assuming that the switching frequency becomes higher. A voltage detection unit that detects a voltage applied to the power switching element,
The switching power supply unit acquires the voltage value detected by the voltage detection unit as the drive information, and changes the operating state based on the voltage value. The smaller the voltage value, the larger the load. 2. The power conversion system according to claim 1 , wherein the switching frequency is increased assuming that the switching frequency becomes higher. A voltage detection unit that detects the voltage applied to the power switching element,
The switching power supply unit acquires a gate voltage value applied to the power switching element as the drive information, and changes the operating state based on the gate voltage value. 2 . The power conversion system according to claim 1 , wherein the switching frequency is increased considering that . When the load changes from a large state to a small state, the switching power supply unit changes the operating state after or at the same time as the load state changes, and changes the load state from the small load state to the large state. 7. The power conversion system according to any one of claims 1 to 6 , wherein when the state of the load changes, the operating state is changed at the same time. wherein the microcomputer transmits the changed drive information to the switching power supply section earlier than the timing of changing the drive state by a predetermined time;
2. The power conversion system according to claim 1, wherein when the load changes from a small state to a large state, the switching power supply section changes the operating state before the load state changes. The drive circuit detects an abnormality of the power switching element,
The switching power supply unit acquires an abnormality detection result of the drive circuit as the drive information, and changes the operating state based on the abnormality detection result, and the abnormality detection result indicates an abnormality of the power switching element. 2. The power conversion system according to claim 1 , wherein the switching frequency is set lower when the abnormality is indicated than when the abnormality of the power switching element is not indicated. The power conversion system according to any one of claims 1 to 9 , wherein the switching power supply section changes the operating state in stages. A plurality of switch groups including at least one of the power switching elements,
Further, a plurality of the switching power supply units are provided, and each switching power supply unit is provided corresponding to each of the switch groups,
11. The power conversion system according to any one of claims 1 to 10 , wherein each switching power supply unit is configured to be able to change the operating state individually without changing the operating state at the same time. 12. The power conversion system according to claim 11 , wherein said plurality of switch groups include a booster circuit, a generator circuit, and an inverter circuit. A plurality of arms including one power switching element,
Furthermore, a plurality of the switching power supply units are provided, and each switching power supply unit is provided corresponding to each of the arms,
The power conversion system according to any one of claims 1 to 10 , wherein each switching power supply acquires the drive information of the corresponding arm and changes the operating state based on the drive information.

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