WO2023238296A1

WO2023238296A1 - Electric power conversion device, motor drive device, and refrigeration cycle application apparatus

Info

Publication number: WO2023238296A1
Application number: PCT/JP2022/023172
Authority: WO
Inventors: 遥松尾; 知宏沓木; 貴昭 ▲高▼原; 浩一有澤; 泰章古庄; 亮祐小林
Original assignee: 三菱電機株式会社
Priority date: 2022-06-08
Filing date: 2022-06-08
Publication date: 2023-12-14

Abstract

This electric power conversion device (1) comprises an inverter (310) that has switching elements (311a–311f) that are housed in a semiconductor package (342), and supplies electric power by the inverter (310) to a motor (314) that drives a load. The semiconductor package (342) is provided with a radiator. The electric power conversion device (1) comprises: a waveform-shape-changing unit (340) that is capable of changing the waveform shape of the switching waveform of at least one switching element among the switching elements (311a–311f); state amount detection units (501, 502) that detect a state amount that indicates an operating state of the electric power conversion device (1); and a waveform shape control signal output unit (420) that sets, according to the state amount, a waveform shape of the switching waveform of the switching elements (311a–311f) when the switching waveform of the switching elements (311a–311f) is to be changed by the waveform-shape-changing unit (340), and outputs a control signal that indicates the set waveform shape.

Description

Power conversion equipment, motor drive equipment, and refrigeration cycle application equipment

The present disclosure relates to a power conversion device, a motor drive device, and a refrigeration cycle application device that performs power conversion.

Conventionally, the switching speed of a switching element has been changed by switching and connecting gate resistors with different gate resistance values to the switching element. For example, in Patent Document 1, in an inverter control device including an inverter main circuit having a plurality of switching elements, when changing the gate drive waveform of the switching element, the gate resistance connected to the switching element is changed using a switch. A technique for switching to a gate resistance with a gate resistance value has been disclosed.

Japanese Patent Application Publication No. 2012-200042

However, according to the above-mentioned conventional technology, a switch is used to switch the gate resistance connected to the switching element. Therefore, in order to increase the number of types of gate drive waveforms, it is necessary to use a large number of gate resistors and switches, resulting in an increase in circuit scale and substrate area.

The present disclosure has been made in view of the above, and an object of the present disclosure is to obtain a power conversion device that can change the switching speed of a switching element while suppressing an increase in circuit scale and substrate area.

In order to solve the above-mentioned problems and achieve the objective, a power conversion device according to the present disclosure includes an inverter having a plurality of switching elements housed in a semiconductor package, and supplies power to a motor that drives a load by the inverter. . The semiconductor package is provided with a heat sink. The power conversion device includes a waveform shape changing section that can change the waveform shape of a switching waveform of at least one switching element among the plurality of switching elements. In addition, the power conversion device includes a state quantity detection unit that detects a state quantity indicating the operating state of the power conversion device, and a waveform shape changing unit that changes the switching waveform of the switching element according to the state quantity detected by the state quantity detection unit. The device includes a waveform shape control signal output unit that sets the waveform shape of the switching waveform of the switching element when changing the waveform shape, and outputs a control signal indicating the set waveform shape.

According to the power conversion device according to the present disclosure, it is possible to change the switching speed of the switching element while suppressing an increase in circuit scale and substrate area.

A diagram showing a configuration example of a power conversion device according to Embodiment 1. A diagram showing an example of turn-on Joule loss, turn-on current, and turn-on voltage when the switching speed of the switching element of the inverter is slowed down in the power conversion device according to Embodiment 1. A diagram showing an example of turn-on Joule loss, turn-on current, and turn-on voltage when the switching speed of the switching element of the inverter is increased in the power conversion device according to Embodiment 1. Diagram showing an example of the relationship between noise and loss generated in general switching elements The first diagram used to explain the effect obtained by changing the switching speed of the switching element of the inverter in the power conversion device according to the first embodiment. A second diagram used to explain the effect obtained by changing the switching speed of the switching element of the inverter in the power conversion device according to Embodiment 1. A diagram showing a configuration example of a waveform shape changing section of the power conversion device according to Embodiment 1. The first diagram showing the relationship between the gate current output by the waveform shape changing unit and the gate voltage indicating the rising speed of the switching element in the power conversion device according to the first embodiment. A second diagram showing the relationship between the gate current output by the waveform shape changing unit and the gate voltage indicating the rising speed of the switching element in the power conversion device according to the first embodiment. A third diagram showing the relationship between the gate current output by the waveform shape changing unit and the gate voltage indicating the rising speed of the switching element in the power conversion device according to the first embodiment. A diagram showing an example of the relationship between the basic pulse output by the basic pulse generation unit and the gate current output by the waveform shape changing unit in the power conversion device according to Embodiment 1. Flowchart used to explain the operation of changing the waveform shape of the switching waveform of the switching element in the power conversion device according to Embodiment 1 Diagram used to explain the first loss line defined in the power conversion device according to Embodiment 1 Diagram used to explain the first loss line and second loss line defined in the power conversion device according to Embodiment 1 Third diagram used to explain the effect obtained by changing the switching speed of the switching element of the inverter in the power conversion device according to Embodiment 1 Fourth diagram used to explain the effect obtained by changing the switching speed of the switching element of the inverter in the power conversion device according to Embodiment 1 A diagram showing changes in switching characteristics under the two operating conditions shown in FIG. A diagram illustrating an example of a hardware configuration that implements a control unit included in the power conversion device according to Embodiment 1. A diagram showing a configuration example of a power conversion device according to Embodiment 2 A diagram used to explain control for changing the waveform shape of a switching waveform of a switching element in the power conversion device according to Embodiment 3. A diagram showing a configuration example of a refrigeration cycle application device according to Embodiment 4

Below, a power conversion device, a motor drive device, and a refrigeration cycle application device according to an embodiment of the present disclosure will be described in detail based on the drawings.

Embodiment 1.
FIG. 1 is a diagram showing a configuration example of a power conversion device 1 according to the first embodiment. Power conversion device 1 is connected to commercial power source 110 and motor 314. The power conversion device 1 converts first AC power based on a power supply voltage supplied from a commercial power source 110 into second AC power having a desired amplitude and phase, and supplies the second AC power to the motor 314. Although the commercial power source 110 is a three-phase AC power source in the example of FIG. 1, it may be a single-phase AC power source. The power converter 1 includes a rectifier 130,

state quantity detectors

501, 502, 505, and 506, a capacitor 210, an inverter 310, and a controller 400. Note that the power conversion device 1 and the motor 314 constitute a motor drive device 2.

The rectifying section 130 includes, for example, a bridge circuit composed of four rectifying elements (not shown) and a reactor. The rectifier 130 rectifies the AC voltage of the first AC power supplied from the commercial power source 110 and converts it into DC power. Note that the rectifier 130 may include a boost chopper circuit or the like.

The capacitor 210 is connected to the output end of the rectifier 130 and smoothes the DC power converted by the rectifier 130. The capacitor 210 is, for example, an electrolytic capacitor, a film capacitor, or the like. Note that the power converter 1 only needs to be able to supply DC power to the inverter 310, so the commercial power supply 110, rectifier 130, and capacitor 210 may be replaced with a DC power supply, a battery, or the like.

The state quantity detection unit 501 detects a state quantity indicating the operating state of the power conversion device 1. The state quantity detection unit 501 detects, for example, the voltage value of the DC power supplied from the capacitor 210 to the inverter 310, the current value of the DC power supplied from the capacitor 210 to the inverter 310, and the like.

The inverter 310 is a power converter connected to both ends of the capacitor 210. The inverter 310 includes switching elements 311a to 311f, which are semiconductor elements, and freewheeling diodes 312a to 312f. These switching elements 311a to 311f and free wheel diodes 312a to 312f are housed in a semiconductor package 342. Although not shown in FIG. 1, the semiconductor package 342 or the substrate on which the semiconductor package 342 is mounted is provided with a heat sink for cooling the switching elements 311a to 311f and the free wheel diodes 312a to 312f. . Examples of the heat radiator include a heat sink (HS), a refrigerant cooler, and the like. A refrigerant cooler is a device that is equipped with a refrigerant circuit, such as an air conditioner, where the refrigerant piping that is part of the refrigerant circuit passes near the circuit board, and is mounted on the circuit board using refrigerant piping made of a thermally conductive material. It lowers the temperature of the element.

The inverter 310 turns on and off the switching elements 311a to 311f under the control of the control unit 400 and converts the DC power output from the rectifier 130 and the capacitor 210 into second AC power having a desired amplitude and phase. AC power is generated and output to the motor 314. The switching elements 311a to 311f are, for example, IGBTs (Insulated Gate Bipolar Transistors), MOSFETs (Metal Oxide Semiconductor Field Effect Tr). transistors), bipolar transistors, etc., but are not limited to these. The circuit configuration of the inverter 310 is not particularly limited, and may be a full bridge circuit, a single-phase bridge circuit, a half bridge circuit, or the like.

Furthermore, in the first embodiment, the inverter 310 includes a waveform shape changing section 340 that can change the waveform shape of the switching waveforms of the switching elements 311a to 311f. The waveform shape changing section 340 can output two or more waveform shapes as the waveform shapes of the switching waveforms of the switching elements 311a to 311f. In the example of FIG. 1, the waveform shape changing unit 340 is configured to be able to change the waveform shape of the switching waveform of the switching elements 311a to 311f, but the waveform shape of the switching waveform of at least one switching element among the switching elements 311a to 311f is The shape can be changed. The inverter 310 may be configured to include a waveform shape changing section 340 for each of the switching elements 311a to 311f. Waveform shape changing section 340 may be a component located outside of inverter 310. The detailed operation of the waveform shape changing section 340 will be described later.

The state quantity detection unit 502 detects a state quantity indicating the operating state of the power conversion device 1. The state quantity detection unit 502 detects, for example, the voltage value of the second AC power supplied from the inverter 310 to the motor 314, which is the load, and the current value of the second AC power, which is supplied from the inverter 310 to the motor 314, which is the load. Detect etc. The state quantity detection unit 505 detects a state quantity indicating the operating state of the power conversion device 1. The state quantity detection unit 505 detects, for example, the current value of the DC power supplied from the capacitor 210 to the inverter 310. The state quantity detection unit 506 detects a state quantity indicating the operating state of the power conversion device 1. The state quantity detection unit 506 detects, for example, current flowing through the switching

elements

311b, 311d, and 311f.

The control unit 400 acquires the state quantities detected by the state

quantity detection units

501, 502, 505, and 506, and controls the inverter 310 based on the obtained state quantities. The operation is controlled, specifically, the on/off of the switching elements 311a to 311f of the inverter 310 is controlled. The control section 400 includes a basic pulse generation section 410 and a waveform shape control signal output section 420.

The basic pulse generation unit 410 calculates a duty ratio according to the state quantities detected by the state

quantity detection units

501, 502, 505, and 506, and also performs basic pulse generation for controlling the operation of the switching elements 311a to 311f of the inverter 310. Generate a pulse. The basic pulse is, for example, a PWM (Pulse Width Modulation) signal having a duty ratio according to the state quantities detected by the state

quantity detection units

501, 502, 505, and 506. The basic pulse generation section 410 outputs basic pulses for controlling the operations of the switching elements 311a to 311f of the inverter 310 to the waveform shape control signal output section 420.

The waveform shape control signal output unit 420 changes the switching waveforms of the switching elements 311a to 311f in the waveform shape changing unit 340 of the inverter 310 according to the state quantities detected by the state

quantity detection units

501, 502, 505, and 506. The waveform shape of the switching waveform of the switching elements 311a to 311f is set, and a control signal indicating the set waveform shape is output. Specifically, the waveform shape control signal output unit 420 turns on and off the switching elements 311a to 311f based on the basic pulse generated by the basic pulse generation unit 410 for controlling the operation of the switching elements 311a to 311f of the inverter 310. At this time, the waveform shape changing unit 340 of the inverter 310 controls the magnitude of the drive signal output to the switching elements 311a to 311f and the timing of outputting the drive signal in order to actually drive the switching elements 311a to 311f. The waveform shape control signal output section 420 outputs a control signal for controlling the operation of the waveform shape modification section 340 to the waveform shape modification section 340 . When the inverter 310 is configured to include a waveform shape changer 340 for each of the switching elements 311a to 311f, that is, to include six waveform shape changers 340, the control unit 400 performs waveform shape control for each waveform shape changer 340. A configuration including a signal output section 420, that is, a configuration including six waveform shape control signal output sections 420 may be used. The waveform shape control signal output section 420 includes a setting section 421, as shown in FIG. The specific operations performed by the setting unit 421 will be described later.

In addition, in the example of FIG. 1, the control unit 400 acquires the state quantities detected by the state

quantity detection units

501, 502, 505, and 506 from the state

quantity detection units

501, 502, 505, and 506, and determines the acquired state. Although the operation of the inverter 310 is controlled based on the amount, the present invention is not limited thereto. The control unit 400 can control the operation of the inverter 310 based on the state quantity acquired from at least one state quantity detection unit among the state

quantity detection units

501, 502, 505, and 506.

Furthermore, in the control unit 400, the basic pulse generation unit 410 and the waveform shape control signal output unit 420 both operate based on the state quantities acquired from the state

quantity detection units

501, 502, 505, and 506. The functions of the basic pulse generation section 410 and the waveform shape control signal output section 420 may be combined into one component.

The motor 314 is a load connected to the power converter 1. The motor 314 is, for example, a motor for driving a compressor. In the normal operation mode, the motor 314 rotates according to the amplitude and phase of the second AC power supplied from the inverter 310, and performs a compression operation. For example, when the compressor is a hermetic compressor, the load torque of the motor 314 that drives the compressor can often be regarded as a constant torque load. The motor 314 may have a Y-connection, a Δ-connection, or a specification in which the Y-connection and the Δ-connection can be switched for motor windings (not shown). Further, in the heating operation mode, the motor 314 is supplied with power for restraint energization supplied from the inverter 310, and heats the liquid refrigerant stagnant inside the compressor.

Note that the load connected to the power conversion device 1 is not limited to the motor 314 for driving the compressor, but may be a fan motor or a motor included in a hand dryer. Further, the load connected to the power converter 1 is not limited to the motor 314, and may be a load other than the motor 314.

With the above-described configuration, the power conversion device 1 according to the first embodiment can change the waveform shapes of the switching waveforms of the switching elements 311a to 311f of the inverter 310 using the waveform shape control signal output section 420 and the waveform shape changing section 340. I can do it. Specifically, the power conversion device 1 can change the switching speed, delay time, etc. when the switching elements 311a to 311f of the inverter 310 perform a switching operation.

FIG. 2 is a diagram showing an example of turn-on Joule loss, turn-on current, and turn-on voltage when the switching speed of switching elements 311a to 311f of inverter 310 is slowed in power converter 1 according to the first embodiment. FIG. 3 is a diagram showing examples of turn-on Joule loss, turn-on current, and turn-on voltage when the switching speed of switching elements 311a to 311f of inverter 310 is increased in power converter 1 according to the first embodiment.

In FIGS. 2 and 3, A indicates turn-on Joule loss, B indicates turn-on current, and C indicates turn-on voltage. In FIGS. 2 and 3, the horizontal axis indicates time. For example, the turn-on current is the current flowing through the switching element 311a, the turn-on voltage is the voltage applied across the switching element 311a, and the turn-on Joule loss is the product of the turn-on current and the turn-on voltage, but the measurement target is the switching element 311a. It is not limited to the element 311a, and other switching elements 311b to 311f may be used. Note that FIGS. 2 and 3 show the differences in each characteristic depending on the switching speed of the switching elements 311a to 311f of the inverter 310, and the specific values of "slow" and "fast" in the switching speed are not particularly important. . As shown in FIGS. 2 and 3, by slowing down the switching speed, the noise represented by the peak value of the turn-on current of B becomes smaller, but the loss represented by the area of the turn-on joule loss of A becomes larger. Furthermore, as shown in FIGS. 2 and 3, by increasing the switching speed, the noise indicated by the peak value of the turn-on current of B becomes larger, but the loss indicated by the area of the turn-on joule loss of A becomes smaller. . That is, in the switching elements 311a to 311f, there is a trade-off relationship between noise and loss generated.

In the power conversion device 1, the waveform shape changing unit 340 is configured by a digital gate driver. Alternatively, in the power conversion device 1, the switching elements 311a to 311f of the inverter 310 and the waveform shape changing section 340 are configured by a digital gate driver module. Thereby, the power conversion device 1 can change the switching speed of the switching elements 311a to 311f of the inverter 310 by changing the command value of the software without changing the hardware, and the switching elements 311a to 311f It is possible to control noise and loss generated in a desired state. Note that the function of the waveform shape control signal output section 420 in the control section 400 can also be configured within a digital gate driver module. In the case of this configuration, the functions of the existing control unit 400 can be used without modification.

FIG. 4 is a diagram showing an example of the relationship between noise and loss generated in a general switching element. As mentioned above, there is a trade-off relationship between noise and loss generated in switching elements. Therefore, in general switching elements, as shown in Figure 4, increasing the switching speed increases noise but decreases loss, and slowing the switching speed decreases noise but increases loss. .

FIG. 5 is a first diagram used to explain the effects obtained by changing the switching speeds of switching elements 311a to 311f of inverter 310 in power conversion device 1 according to Embodiment 1. Even if the power converter 1 is operated within the noise range specified by the product in which the power converter 1 is installed, when the load state of the motor 314 changes from light load to heavy load, the power converter 1 will cause the noise shown in FIG. 5 to change from light load to heavy load. As such, the curve representing the characteristics of noise and loss generated in the switching elements 311a to 311f moves toward the upper right, resulting in an increase in noise. That is, in the power conversion device 1, the heavier the load, the more noise increases. Therefore, the power converter 1 can reduce the noise generated in the switching elements 311a to 311f by slowing down the switching speed of the switching elements 311a to 311f. Similarly, even if the power converter 1 is operated within the loss range specified by the product in which the power converter 1 is installed, when the load state of the motor 314 changes from light load to heavy load, the As shown in FIG. 5, the curve showing the characteristics of noise and loss generated in the switching elements 311a to 311f moves toward the upper right, and as a result, the loss increases. That is, in the power conversion device 1, the heavier the load, the more the loss increases. Therefore, the power conversion device 1 can reduce the loss generated in the switching elements 311a to 311f by increasing the switching speed of the switching elements 311a to 311f.

When the load state of the motor 314 changes from a light load to a heavy load, the waveform shape control signal output unit 420 controls the noise generated in the switching elements 311a to 311f while satisfying the specified requirements. The waveform shapes of the switching waveforms of the switching elements 311a to 311f are changed to reduce the loss caused by the switching elements 311a to 311f. Alternatively, when the load state of the motor 314 changes from a light load to a heavy load, the waveform shape control signal output section 420 outputs the switching elements 311a to 311f while satisfying the specified requirements for losses generated in the switching elements 311a to 311f. The waveform shapes of the switching waveforms of the switching elements 311a to 311f are changed so as to reduce the noise generated in the switching elements 311a to 311f.

FIG. 6 is a second diagram used to explain the effects obtained by changing the switching speeds of switching elements 311a to 311f of inverter 310 in power conversion device 1 according to Embodiment 1. The power conversion device 1, specifically the waveform shape changing unit 340, divides a turn-on period or a turn-off period into two or more periods in one switching operation of the switching elements 311a to 311f, and in each divided period, The amplitudes of the gate currents or gate voltages for the switching elements 311a to 311f are changed to different magnitudes. By optimizing the switching waveforms of the switching elements 311a to 311f as shown in FIG. 6, the power converter 1 can reduce the power generated in the switching elements 311a to 311f, which could not be achieved with general switching elements as shown in FIG. It is possible to obtain noise and loss characteristics that

Here, the configuration of the waveform shape changing section 340 will be explained. Here, as an example, in order to simplify the explanation, a case will be described in which the waveform shape changing section 340 can change the waveform shape of the switching waveform of one switching element 311a. FIG. 7 is a diagram illustrating a configuration example of the waveform shape changing unit 340 of the power conversion device 1 according to the first embodiment. FIG. 7 is also a diagram showing a configuration example of one digital gate driver configured by the waveform shape changing section 340 and the switching element 311a. As shown in FIG. 1, the waveform shape changing section 340 is included in the inverter 310, which is a power converter including a switching element 311a. The waveform shape changing unit 340 includes n PMOSs (P-channel Metal Oxide Semiconductor) which are P-channel MOSFETs for turn-on, n PreDrivers for operating the n PMOSs, and n PreDrivers for turn-off. It includes an NMOS (N-channel Metal Oxide Semiconductor) that is an N-channel MOSFET, and n PreDrivers for operating the n NMOS.

The waveform shape changing section 340 is connected to the control power supply Vdd and the ground GND. The waveform shape changing section 340 changes the number of PMOSs or NMOSs to be operated based on the control signal from the waveform shape control signal output section 420, thereby outputting it to the switching element 311a in each period of the turn-on period and the turn-off period. The amplitude value of the gate current _IG , which is the drive signal, can be changed in n ways to adjust the switching speed of the switching element 311a. The waveform shape changing unit 340 can increase the absolute value of the gate current _IG output to the switching element 311a as the number of PMOSs or NMOSs to be operated increases, and the switching speed of the switching element 311a can be increased. can. In addition, the waveform shape changing unit 340 can finely adjust the switching speed of the switching element 311a as the number of PMOSs and NMOSs provided therein is large, and the faster the response to increase/decrease the gate current _IG , the more finely the switching speed of the switching element 311a can be adjusted. It is possible to finely adjust the gate current _IG during the switching period. The control signal from the waveform shape control signal output section 420 may be an analog signal or a digital signal as long as it can change the number of PMOSs or NMOSs operated by the waveform shape changing section 340. Furthermore, although the example in FIG. 7 shows that there are m control signals in parallel from the waveform shape control signal output section 420 to the waveform shape change section 340, this is just an example, and the number of control signals is m. Not limited. The number of control signals may be a number that can indicate whether each PMOS and each NMOS can operate, or it may be one as long as it is an analog signal that indicates voltage or the like.

FIG. 8 is a first diagram showing the relationship between the gate current IG output by the waveform shape changing unit 340 and _{the gate voltage VG} _indicating the rising speed of the switching element 311a in the power conversion device 1 according to the first embodiment. be. FIG. 9 is a second diagram showing the relationship between the gate current _IG output by the waveform shape changing unit 340 and the gate voltage _VG indicating the rising speed of the switching element 311a in the power conversion device 1 according to the first embodiment. be. As shown in FIGS. 8 and 9, the waveform shape changing unit 340 can increase the rise of the gate voltage _VG , that is, increase the switching speed of the switching element 311a, as the output gate current _IG increases. can. Further, as shown in FIGS. 8 and 9, the waveform shape changing unit 340 slows down the rise of the gate voltage _VG , that is, the switching speed of the switching element 311a, as the gate current _IG to be output is made smaller. be able to. As a result, as shown in FIG. 4, when the power conversion device 1 wants to reduce the noise generated in the switching element 311a, the output gate current _IG is decreased to slow the switching speed, and the noise generated in the switching element 311a is reduced. When it is desired to reduce the loss, the output gate current _IG can be increased to increase the switching speed. Note that the waveforms of the gate current _IG and gate voltage _VG shown in FIGS. 8 and 9 are ideal examples, and as shown in FIGS. 2 and 3, in reality, the gate current _IG is constant. It will take time to reach the current value.

FIG. 10 is a third diagram showing the relationship between the gate current _IG output by the waveform shape changing unit 340 and the gate voltage _VG indicating the rising speed of the switching element 311a in the power conversion device 1 according to the first embodiment. be. As shown in FIG. 10, the waveform shape changing unit 340 can divide the turn-on period and change the magnitude of the gate current _IG in each period. That is, the waveform shape changing section 340 can finely adjust the magnitude of the gate current _IG during one turn-on period. As a result, the power converter 1 can reduce the noise generated in the switching element 311a while reducing the noise generated in the switching element 311a, as shown in FIG. 6, compared to the case where the same gate current _IG is output during the turn-on period. control can be performed to reduce the loss caused by

Although the turn-on period of the switching element 311a has been described as an example using FIGS. 8 to 10, the same applies to the turn-off period of the switching element 311a. FIG. 11 is a diagram illustrating an example of the relationship between the fundamental pulse outputted by the fundamental pulse generating section 410 and the gate current _IG outputted by the waveform shape changing section 340 in the power conversion device 1 according to the first embodiment. In FIG. 11, it is assumed that |Ig2|>|Ig1|. The waveform shape changing unit 340 divides the period in which the gate current _IG is output during the turn-on period of the switching element 311a, first outputs the gate current _IG with a large amplitude current Ig2, and then outputs the gate current IG with a small amplitude current Ig1. The gate current _IG of the current Ig1 with a small amplitude may be outputted first, and then the gate current _IG of the current Ig2 with _a large amplitude may be outputted. Similarly, the waveform shape changing unit 340 divides the period in which the gate current _IG is output during the turn-off period of the switching element 311a, first outputs the gate current IG with a large amplitude - Ig2, and then outputs the gate current _IG with a large amplitude. You may output the gate current _IG with a small current -Ig1, or first output the gate current _IG with a small amplitude current -Ig1, and then output the gate current _IG with a large amplitude current -Ig2. You can also output it.

In this manner, the waveform shape changing section 340 changes the waveform shape of the switching waveform of the switching element 311a between the turn-on period and the turn-off period of the switching element 311a based on the waveform shape set by the waveform shape control signal output section 420. At least one period can be divided into two or more periods, and the amplitude of the gate current _IG to the switching element 311a can be changed to a different magnitude in each divided period. Further, the waveform shape changing section 340 includes a plurality of transistors, and changes the amplitude of the gate current _IG by changing the number of transistors to be operated based on the waveform shape set by the waveform shape control signal output section 420. can do.

Further, the waveform shape changing section 340 can change the output pattern of the gate current _IG every switching period of the switching element 311a. The waveform shape changing unit 340 can change the switching waveform to a different waveform shape every switching period of the switching element 311a while the power conversion device 1 is in operation. In this case, the waveform shape control signal output section 420 can change the waveform shape of the switching waveform of the switching element 311a at the same cycle as the switching cycle of the switching element 311a. The waveform shape control signal output unit 420 may change the waveform shape of the switching waveform of the switching element 311a at a cycle that is a positive integer multiple of the switching cycle of the switching element 311a.

Note that, regarding the configuration of the waveform shape changing unit 340, the configuration of the waveform shape changing unit 340 shown in FIG. 7 is an example, and is not limited thereto. The waveform shape changing unit 340 may use a transistor other than a MOS (Metal Oxide Semiconductor) for internal use.

The waveform shape changing unit 340 uses digital control using a plurality of MOSs to finely control the switching speed of the switching element 311a compared to analog control that physically switches the gate resistance as described in Patent Document 1. can be adjusted to Furthermore, since the resistance value of the gate resistor varies depending on the temperature, accuracy with respect to temperature variation may become a problem. In contrast, with digital gate drivers, this problem does not occur. Therefore, the waveform shape changing unit 340 configured by the digital gate driver can adjust the switching speed with high accuracy.

Further, in the above example, the waveform shape changing unit 340 changes the number of PMOSs or NMOSs to be operated according to the acquired control signal, and applies a gate current _IG to the switching element 311a according to the number of PMOSs or NMOSs to be operated. However, the output is not limited to this. The waveform shape changing unit 340 stores in advance an output pattern, that is, a waveform shape, of the gate current _IG in accordance with the control signal, and outputs the gate current _IG in the output pattern, that is, the waveform shape, in accordance with the acquired control signal. Good too. Further, the waveform shape changing unit 340 stores the control signal acquired in the past and the output pattern, that is, the waveform shape, of the gate current _IG for the control signal acquired in the past, and stores it when the same control signal is acquired. The gate current _IG may be output in the same output pattern, ie, waveform shape. The waveform shape changing section 340 can reduce the processing load when outputting the gate current _IG by storing the output pattern, that is, the waveform shape, of the gate current _IG according to the control signal.

Further, in the example of FIG. 4, the waveform shape changing unit 340 adjusts the switching speed of the switching element 311a by changing the gate current _IG as a drive signal output to the switching element 311a, and changes the switching waveform of the switching element 311a. Although the waveform shape was changed, the present invention is not limited to this. The waveform shape changing unit 340 sets the drive signal output to the switching element 311a to a gate voltage _VG , and by changing the gate voltage _VG , similarly adjusts the switching speed of the switching element 311a, and changes the switching waveform of the switching element 311a. The waveform shape of can be changed.

In this way, the waveform shape changing section 340 changes the waveform shape of the switching waveform of the switching element 311a between the turn-on period and the turn-off period of the switching element 311a based on the control signal output from the waveform shape control signal output section 420. At least one period can be divided into two or more periods, and the amplitude of the gate voltage V _G applied to the switching element 311a can be changed to a different magnitude in each divided period. Further, the waveform shape changing unit 340 includes a plurality of transistors, and changes the amplitude of the gate voltage V _G by changing the number of transistors to be operated based on the control signal output from the waveform shape control signal output unit 420. can do.

FIG. 12 is a flowchart used to explain the operation of changing the waveform shapes of the switching waveforms of the switching elements 311a to 311f in the power conversion device 1 according to the first embodiment. In the power conversion device 1, the basic pulse generation unit 410 generates basic pulses for driving the switching elements 311a to 311f of the inverter 310 based on the state quantities acquired from the state

quantity detection units

501, 502, 505, and 506. (Step S1). In this way, in the control unit 400, the basic pulse generation unit 410 generates a basic pulse based on the state quantities acquired from the state

quantity detection units

501, 502, 505, and 506, and turns on the switching elements 311a to 311f. Determine timing and turn-off timing. The basic pulse generation section 410 outputs the generated basic pulse to the waveform shape control signal output section 420.

The waveform shape control signal output section 420 performs switching of the switching elements 311a to 311f of the inverter 310 based on the basic pulse obtained from the basic pulse generation section 410 and the physical quantities obtained from the state

quantity detection sections

501, 502, 505, and 506. Set the waveform shape to change the waveform shape of the waveform. In this way, in the control section 400, the waveform shape control signal output section 420 outputs the switching element 311a determined by the basic pulse generation section 410 based on the state quantities acquired from the state

quantity detection sections

501, 502, 505, and 506. The waveform shape of the switching waveform at the timing of turning on and turning off 311f is set. The waveform shape control signal output section 420 outputs a control signal that can change the magnitude and output timing of the drive signal according to the set waveform shape to the waveform shape change section 340 (step S2).

The waveform shape changing unit 340 acquires the waveform shape of the gate current _IG output to the switching elements 311a to 311f of the inverter 310, that is, the waveform shape of the switching waveform of the switching elements 311a to 311f, from the waveform shape control signal output unit 420. It is changed based on the control signal (step S3). The waveform shape changing section 340 outputs the gate current _IG after changing the waveform shape to the switching elements 311a to 311f of the inverter 310.

As described above, the power conversion device 1 according to the first embodiment uses the functions of the basic pulse generation section 410 and the waveform shape control signal output section 420 described above to perform driving for driving the switching elements 311a to 311f of the inverter 310. Signal magnitude and output timing can be changed. The power conversion device 1 according to the first embodiment can obtain various effects by applying this function to a power conversion device including a radiator.

FIG. 13 is a diagram used to explain the first loss line L1 defined in the power conversion device 1 according to the first embodiment. FIG. 14 is a diagram used to explain the first loss line L1 and the second loss line L2 defined in the power conversion device 1 according to the first embodiment. FIG. 15 is a third diagram used to explain the effect obtained by changing the switching speeds of switching elements 311a to 311f of inverter 310 in power converter 1 according to the first embodiment.

In FIG. 13, the first loss line L1 is a boundary line representing the loss limit allowed in the power converter 1 when the power converter 1 is not equipped with a radiator. As mentioned above, slowing the switching speed reduces noise and increases loss. In order to reduce noise, it is possible to slow the switching speed by changing the waveform shape of the switching waveform of the switching elements 311a to 311f, but if the loss becomes large, it is possible to reduce the switching speed of at least one of the switching elements 311a to 311f. The device may experience thermal runaway. That is, the first loss line L1 is a boundary line indicating a loss boundary at which at least one of the switching elements 311a to 311f does not cause thermal runaway. Therefore, as shown in FIG. 13, if the region from the vertical axis, which means zero loss, to the first loss line L1 is expressed as "R1", this region R1 corresponds to the power conversion device 1 without a heat sink. This means an operational area. Note that although the first loss line L1 is shown as a straight line in FIG. 13, it does not necessarily have to be a straight line. Furthermore, it goes without saying that the first loss line L1 and the region R1 will have different curves and different regions even if the switching elements are the same but if the driving target is different.

Further, in FIG. 14, the second loss line L2 is a boundary line representing the loss limit allowed in the power converter 1 when the power converter 1 is equipped with a radiator. As shown in FIG. 14, the area from the first loss line L1 to the second loss line L2 is represented by "R2". When the power converter 1 includes a radiator, the loss limit allowed in the power converter 1 is relaxed by the radiator. Therefore, when the power conversion device 1 includes a heat sink, it becomes possible to further reduce the switching speed and further reduce noise. Thereby, the region in which the power conversion device 1 can operate can be expanded to region R2 in addition to region R1. Note that even if the switching elements are the same, the second loss line L2 and the region R2 may have different curves and different regions if the driving target is different, or if the size of the radiator and the cooling characteristics of the radiator are different. Needless to say.

On the left and right sides of FIG. 15, the approximate sizes and approximate positional relationships of the waveform shape changing unit 340, the semiconductor package 342, and the noise countermeasure component 322 mounted on the board 320 are schematically shown. Further, on the right side of FIG. 15, a radiator 344 is shown that is provided to cover the waveform shape changing section 340 and the semiconductor package 342 in order to suppress a temperature rise due to heat generation in the waveform shape changing section 340 and the semiconductor package 342. ing. Note that although FIG. 15 shows an example in which the heat radiator 344 is provided on the mounting surface of the waveform shape changing section 340 and the semiconductor package 342, the present invention is not limited to this configuration. The heat sink 344 may be provided on a surface opposite to the mounting surface of the waveform shape changing section 340 and the semiconductor package 342.

As described above, by providing a heat radiator, it is possible to expand the allowable loss limit range in the power conversion device 1. Further, as described above, noise can be reduced by slowing down the switching speed and increasing loss. Therefore, in the power converter 1 according to the first embodiment, the waveform shape changing unit 340 and the waveform shape control signal output unit 420 perform switching so as to operate actively in the region R2 under operating conditions where noise becomes large. The waveform shapes of the switching waveforms of the elements 311a to 311f are changed. In this way, as shown in FIG. 15, by providing the heat radiator 344, the area occupied by the noise countermeasure component 322 can be reduced. As a result, the substrate area, which is the area of the substrate 320, can be reduced. Note that by including the heatsink 344, the size in the direction perpendicular to the board surface, that is, in the height direction increases, but the board 320 originally has components that have sizes in the height direction, such as electrolytic capacitors and terminals. Since there are a large number of heat sinks, an increase in the length in the height direction due to the heat radiator is hardly a problem.

FIG. 16 is a fourth diagram used to explain the effects obtained by changing the switching speeds of switching elements 311a to 311f of inverter 310 in power conversion device 1 according to Embodiment 1. FIG. 17 is a diagram showing changes in switching characteristics under the two operating conditions shown in FIG. 16.

The upper graph in FIG. 16 shows the simulation results of analyzing the operation of the switching elements 311a to 311f when the inverter 310 is operated under certain operating conditions, using the HS area, element loss, and temperature excess as parameters. There is. Here, the HS area is the area of the heat sink when the heat sink is viewed from a direction perpendicular to the substrate surface, assuming that the heat sink is a heat sink. The element loss means the loss of the switching elements 311a to 311f. Excess temperature indicates the amount of increase or decrease in temperature of the switching elements 311a to 311f. Further, the horizontal axis of the graph in FIG. 16 represents the HS area, and the vertical axis of the graph in FIG. 16 represents the temperature excess due to element loss. In addition, the table on the lower side of FIG. 16 shows the parameters of HS area, element loss, and overtemperature under each operating condition for the three operating conditions (1) to (3) shown on the upper side of FIG. 16. Each value is shown. Regarding the HS area and element loss, the values for operating conditions (2) and (3) are normalized and shown based on the value for operating condition (1).

The simulation results shown in FIG. 16 will be explained. First, when the inverter 310 operates under operating condition (1), it is confirmed that the temperature exceeds the specified temperature that the elements can withstand by 1.4 [° C.]. Note that, as described above, the HS area and element loss at this time are normalized as 1. In order to keep the temperature exceedance within the specified range, as operating condition (2), the HS area is set to be 1.3 times that of operating condition (1). FIG. 16 shows that by doing this, the excess temperature can be suppressed to −0.1 [° C.]. That is, in order to suppress the temperature exceedance to −0.1 [° C.], the HS area is required to be 1.3 times the operating condition (1). However, increasing the HS area is not a good idea, and it is often difficult to increase the HS area. Therefore, under operating condition (3), the element loss in the inverter 310 is reduced by 10% using the method of changing the waveform shape of the switching waveform described above without changing the HS area. FIG. 16 shows that this allows the temperature excess to be suppressed to −0.1 [° C.].

FIG. 17 shows an image of control for transitioning from operating condition (1) to operating condition (3). In FIG. 17, A is an operating point corresponding to operating condition (1), and is located on the right side of the second loss line L2. Further, B is an operating point corresponding to operating condition (3), and is located on the left side of the second loss line L2. Waveform shape control signal output section 420 changes the waveform shape of the switching waveforms of switching elements 311a to 311f of inverter 310 so that element loss in inverter 310 increases. Then, the waveform shape changing section 340 changes the waveform shapes of the switching waveforms of the switching elements 311a to 311f based on the control signal obtained from the waveform shape control signal output section 420. In this way, the operating point on the switching characteristic curve shown in FIG. 17 can be moved from operating point A to operating point B. This makes it possible to appropriately adjust the element loss in the switching elements 311a to 311f while suppressing noise generated in the power converter 1, thereby preventing thermal runaway of the switching elements 311a to 311f.

Next, the hardware configuration of the control unit 400 included in the power conversion device 1 will be described. FIG. 18 is a diagram illustrating an example of a hardware configuration that implements the control unit 400 included in the power conversion device 1 according to the first embodiment. The control unit 400 is realized by a processor 91 and a memory 92.

The processor 91 is a CPU (Central Processing Unit, also referred to as a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, a DSP (Digital Signal Processor)), or a system LSI (Large Scale Intel). gration). The memory 92 includes RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), and EEP. Non-volatile or volatile memory such as ROM (registered trademark) (Electrically Erasable Programmable Read Only Memory) An example is semiconductor memory. Furthermore, the memory 92 is not limited to these, and may be a magnetic disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disc).

As described above, the power conversion device according to the first embodiment includes an inverter having a plurality of switching elements housed in a semiconductor package, and the inverter supplies power to a motor that drives a load. The power conversion device includes a waveform shape changing section, a state quantity detection section, and a waveform shape control signal output section, and the semiconductor package is provided with a heat sink. The waveform shape control signal output section sets the waveform shape of the switching waveform of the switching element when the waveform shape changing section changes the switching waveform of the switching element according to the state quantity detected by the state quantity detection section. The waveform shape changing section changes the waveform shape of the switching waveform of the switching element based on the waveform shape set by the waveform shape control signal output section. Thereby, the power conversion device can change the switching speed of the switching element while suppressing an increase in circuit scale and substrate area.

Further, in the power conversion device according to the first embodiment, the waveform shape changing unit adjusts the turn-on period of the switching element with respect to the waveform shape of the switching waveform of the switching element based on the waveform shape set by the waveform shape control signal output unit. At least one of the turn-off periods and the turn-off period is divided into two or more periods, and the amplitude of the gate current or gate voltage for the switching element can be changed to a different magnitude in each divided period. According to the power conversion device configured in this way, it is possible to finely adjust the gate current or gate voltage output to the switching element in one switching period, and it is possible to finely adjust the gate current or gate voltage output to the switching element in one switching period, which could not be achieved with the method of Patent Document 1 etc. It is possible to realize the waveform shape of the switching waveform.

Further, the power conversion device according to the first embodiment recognizes as a first loss line a boundary line representing a loss limit allowed in the power conversion device when the power conversion device is not equipped with a heatsink, and is equipped with a heatsink. A boundary line representing the allowable loss limit in a power converter is sometimes recognized as a second loss line. The waveform shape control signal output unit sets the waveform shape of the switching waveform of the switching element so that the power converter can operate in a region where the loss exceeds the first loss line and does not exceed the second loss line. According to the power converter configured in this way, it is possible to operate the power converter by effectively utilizing the ability of the radiator, so it is possible to expand the range of allowable loss limits in the power converter. can. This makes it possible to reduce noise by slowing down the switching speed and increasing loss, so the area occupied by noise countermeasure components can be made smaller than in the past, and the board area can be reduced.

Embodiment 2.
FIG. 19 is a diagram showing a configuration example of a power conversion device 1A according to the second embodiment. In the second embodiment, the power conversion device 1A and the motor 314 constitute a motor drive device 2A. Moreover, in the power conversion device 1A according to the second embodiment, a physical quantity detection unit 504 is added to the configuration of the power conversion device 1 shown in FIG. Further, in FIG. 19, the control section 400 is replaced with a control section 400A. Further, in the control section 400A, the basic pulse generation section 410 is replaced with a basic pulse generation section 410A, the waveform shape control signal output section 420 is replaced with a waveform shape control signal output section 420A, and the setting section 421 is replaced with a setting section 421A. has been replaced by The other configurations are the same or equivalent to the power conversion device 1 shown in FIG. 1, and the same or equivalent components are denoted by the same reference numerals, and redundant explanations will be omitted.

The physical quantity detection unit 504 detects a physical quantity that is correlated with the loss that occurs in the power conversion device 1A due to switching of the switching elements 311a to 311f included in the inverter 310. The physical quantity detection unit 504 is, for example, a thermocouple, and detects the physical quantity correlated with the loss generated in the power conversion device 1A by detecting the heat generated in the installed portion, that is, the temperature. When the physical quantity detection unit 504 is a thermocouple, the physical quantity detection unit 504 is installed, for example, inside the semiconductor package 342, in or around the radiator 344, on the substrate 320, or the like. Although the power conversion device 1A includes one physical quantity detection section 504 in the example of FIG. 19, it may include a plurality of physical quantity detection sections 504.

The setting unit 421A sets the waveform shape of the switching waveform of the switching elements 311a to 311f based on the physical quantity detected by the physical quantity detection unit 504 and the loss threshold set based on the second loss line L2 described above. do. Specifically, when the physical quantity detected by the physical quantity detection unit 504 exceeds the loss threshold, the setting unit 421A increases the switching speed when driving the switching elements 311a to 311f, thereby increasing the switching speed of the switching elements 311a to 311f. control losses that occur. By controlling in this manner, thermal runaway of the switching elements 311a to 311f can be reliably prevented.

As described above, according to the power conversion device according to the second embodiment, the waveform shape control signal output section is configured to output a loss that is set based on the physical quantity detected by the physical quantity detection section and the second loss line. The waveform shape of the switching waveform of the switching element is set based on the threshold value. The waveform shape changing section changes the waveform shape of the switching waveform of the switching element based on the waveform shape set by the waveform shape control signal output section. This makes it possible to reliably prevent thermal runaway of the switching element even when the power converter device is operated by making full use of the capability of the radiator.

Embodiment 3.
In the third embodiment, control for changing the waveform shape of the switching waveforms of the switching elements 311a to 311f based on the amount of electric power supplied to the motor 314 will be described. The control according to the third embodiment can be performed using the power conversion device 1 shown in FIG. 1.

FIG. 20 is a diagram used to explain the control for changing the waveform shapes of the switching waveforms of the switching elements 311a to 311f in the power conversion device according to the third embodiment. FIG. 20 shows three switching characteristic curves when the load states of the motor 314 are light load, medium load, and heavy load. In FIG. 20, when the power conversion device 1 is operating at operating point C, which is a medium load, for example, when the load state becomes a heavy load, the power converter 1 shifts to operating point D. If the operation continues in this state, the switching elements 311a to 311f may experience thermal runaway. Therefore, in the third embodiment, the switching characteristics are changed so that the operating point D shifts to the operating point E. This control can be performed based on the amount of power supplied to motor 314. The amount of electric power supplied to the motor 314 can be calculated using the state quantity detected by the state quantity detection unit 502. As described above, the state quantity detection unit 502 detects the voltage value of the second AC power supplied from the inverter 310 to the motor 314 and the current value of the second AC power supplied from the inverter 310 to the motor 314. It is possible to detect.

Note that the determination of what kind of switching characteristics to use depending on the load state of the motor 314 may be realized by holding previously measured data as a table, or by using the physical quantities described in Embodiment 2. This may be realized by using the detection value of the detection unit 504. Moreover, although the example in which the amount of electric power supplied to the motor 314 is calculated using the state quantity detected by the state quantity detection unit 502 has been described above, the present invention is not limited to this example. The amount of electric power supplied to the motor 314 can also be calculated using a voltage command value and a current command value that are used or generated in the control unit 400.

As described above, according to the power conversion device according to the third embodiment, the waveform shape control signal output section sets the waveform shape of the switching waveform of the switching element based on the amount of power supplied to the motor. According to this control, even if the load condition of the motor suddenly changes, it is possible to respond quickly. This makes it possible to reliably prevent thermal runaway of the switching element even when the power converter device is operated by making full use of the capability of the radiator.

Embodiment 4.
FIG. 21 is a diagram showing a configuration example of a refrigeration cycle application device 900 according to the fourth embodiment. Refrigeration cycle application equipment 900 according to the fourth embodiment includes the power conversion device 1 described in the first embodiment. The refrigeration cycle application device 900 according to the fourth embodiment can also include the power conversion device 1A described in the second embodiment. The refrigeration cycle application device 900 according to the fourth embodiment can be applied to products including a refrigeration cycle, such as air conditioners, refrigerators, freezers, and heat pump water heaters. Note that in FIG. 21, components having the same functions as those in the first embodiment are given the same reference numerals as in the first embodiment.

Refrigeration cycle application equipment 900 includes a compressor 315 with built-in motor 314 in Embodiment 1, a four-way valve 902, an indoor heat exchanger 906, an expansion valve 908, and an outdoor heat exchanger 910 that connect refrigerant piping 912. It is attached through.

A compression mechanism 904 that compresses the refrigerant and a motor 314 that operates the compression mechanism 904 are provided inside the compressor 315.

The refrigeration cycle applicable equipment 900 can perform heating operation or cooling operation by switching the four-way valve 902. The compression mechanism 904 is driven by a variable speed controlled motor 314.

During heating operation, as shown by the solid arrow, the refrigerant is pressurized by the compression mechanism 904 and sent out, passing through the four-way valve 902, indoor heat exchanger 906, expansion valve 908, outdoor heat exchanger 910, and four-way valve 902. Returning to the compression mechanism 904.

During cooling operation, the refrigerant is pressurized by the compression mechanism 904 and sent out, passing through the four-way valve 902, the outdoor heat exchanger 910, the expansion valve 908, the indoor heat exchanger 906, and the four-way valve 902, as shown by the dashed arrow. Returning to the compression mechanism 904.

During heating operation, the indoor heat exchanger 906 acts as a condenser and releases heat, and the outdoor heat exchanger 910 acts as an evaporator and absorbs heat. During cooling operation, the outdoor heat exchanger 910 acts as a condenser and releases heat, and the indoor heat exchanger 906 acts as an evaporator and absorbs heat. The expansion valve 908 reduces the pressure of the refrigerant and expands it.

Note that even if the refrigeration cycle application equipment 900 is operated within the specified noise range, when the load state of the motor 314 changes from light load to heavy load, the switching elements 311a to 311f as shown in FIG. The curve showing the characteristics of noise and loss generated in such cases moves toward the upper right, resulting in an increase in noise. Therefore, the refrigeration cycle application equipment 900 can reduce the noise generated in the switching elements 311a to 311f by slowing down the switching speed of the switching elements 311a to 311f. Similarly, even if the refrigeration cycle application equipment 900 is operated within the specified loss range, when the load state of the motor 314 changes from light load to heavy load, switching elements 311a to 311a as shown in FIG. The curve showing the characteristics of noise and loss generated in 311f etc. moves toward the upper right, and as a result, the loss increases. Therefore, the refrigeration cycle applicable equipment 900 can reduce the loss generated in the switching elements 311a to 311f by increasing the switching speed of the switching elements 311a to 311f.

Here, in the power conversion device 1 included in the refrigeration cycle application equipment 900, the digital gate driver configured by the waveform shape changing section 340 and the switching elements 311a to 311f included in the inverter 310 has a high surge voltage when the switching speed is high. Therefore, a lot of electromagnetic noise is generated. When the refrigeration cycle application equipment 900 uses a combustible refrigerant, there is a possibility that the refrigerant will be combusted due to discharge caused by electromagnetic noise when the refrigerant leaks. Therefore, the refrigeration cycle application equipment 900 sets the switching speed of the digital gate driver included in the power conversion device 1 according to the combustibility of the refrigerant used in the refrigeration cycle application equipment 900. For example, the refrigeration cycle application equipment 900 decreases the switching speed of the digital gate driver included in the power converter 1 as the flammability of the refrigerant used in the refrigeration cycle application equipment 900 increases. The refrigeration cycle application equipment 900 can reduce the surge voltage by slowing down the switching speed of the digital gate driver, and by suppressing the occurrence of discharge caused by electromagnetic noise, even if refrigerant leaks from the refrigeration cycle application equipment 900. However, combustion can be prevented.

Refrigerants used in the refrigeration cycle application equipment 900 include, for example, R1234yf, R1234ze (E), R1243zf, HFO1123, HFO1132 (E), R1132a, CF3I, R290, R463A, R466A, R454A, R454B, and R454C.

The configurations shown in the embodiments above are merely examples, and can be combined with other known techniques, or can be combined with other embodiments, within the scope of the gist. It is also possible to omit or change part of the configuration.

1,1a electric power conversion device, 2,2A motor drive device, 91 processor, 92 memory, 110 commercial power supply, 130 stream, 210 capacitors, 310 inverters, 311a to 311F switching elements, 312a -312F Reduced duods, 315, 315 Compressor, 320 Board, 322 Noise countermeasure parts, 340 Waveform shape changing section, 342 Semiconductor package, 344 Heatsink, 400, 400A Control section, 410, 410A Basic pulse generation section, 420, 420A Waveform shape control signal output section, 421 , 421A Setting section, 501, 502, 505, 506 State quantity detection section, 504 Physical quantity detection section, 900 Refrigeration cycle application equipment, 902 Four-way valve, 904 Compression mechanism, 906 Indoor heat exchanger, 908 Expansion valve, 910 Outdoor heat exchange 912 Refrigerant piping.

Claims

A power conversion device comprising an inverter having a plurality of switching elements housed in a semiconductor package, the inverter supplying power to a motor that drives a load,
a waveform shape changing unit capable of changing the waveform shape of a switching waveform of at least one switching element among the plurality of switching elements;
a state quantity detection unit that detects a state quantity indicating an operating state of the power converter;
In accordance with the state quantity, the waveform shape changing unit sets a waveform shape of the switching waveform of the switching element when changing the switching waveform of the switching element, and outputs a control signal indicating the set waveform shape. a waveform shape control signal output section;
Equipped with
A power conversion device, wherein the semiconductor package is provided with a heat sink.
The waveform shape changing section changes the waveform shape of the switching waveform of the switching element to at least one of a turn-on period and a turn-off period of the switching element, based on the waveform shape set by the waveform shape control signal output section. The power conversion device according to claim 1, wherein the period is divided into two or more, and the amplitude of the gate current or gate voltage for the switching element can be changed to a different magnitude in each divided period.
A first loss line is a boundary line representing a loss limit allowable in the power converter when the heat radiator is not provided, and a loss limit allowable in the power converter when the heat radiator is provided. When the boundary line representing the second loss line is set as the second loss line,
The waveform shape control signal output section adjusts the switching waveform of the switching element so that the power converter can operate in a region where the loss exceeds the first loss line and does not exceed the second loss line. The power conversion device according to claim 1 or 2, wherein a waveform shape is set.
comprising a detection unit that detects a physical quantity correlated with loss occurring in the inverter,
The waveform shape control signal output unit sets the waveform shape of the switching waveform of the switching element based on the physical quantity and a loss threshold set based on the second loss line. The power conversion device described.
The state quantity is the amount of electric power supplied to the motor,
The power conversion device according to any one of claims 1 to 4, wherein the waveform shape control signal output unit sets the waveform shape of the switching waveform of the switching element based on the amount of electric power.
The power conversion device according to any one of claims 1 to 5, wherein the radiator is a heat sink.
The power conversion device according to any one of claims 1 to 5, wherein the radiator is a refrigerant cooler.
The power conversion device according to any one of claims 1 to 7, wherein the inverter including the switching element is configured to include the waveform shape changing section.
A motor drive device comprising the power conversion device according to any one of claims 1 to 8.
A refrigeration cycle applicable device comprising the power conversion device according to any one of claims 1 to 8.
The refrigerant used in the refrigeration cycle application equipment is any one of R1234yf, R1234ze (E), R1243zf, HFO1123, HFO1132 (E), R1132a, CF3I, R290, R463A, R466A, R454A, R454B, and R454C. 10. The refrigeration cycle applicable device according to 10.
The refrigeration cycle application equipment according to claim 11, wherein a switching speed of a digital gate driver included in the power conversion device is set depending on combustibility of the refrigerant.