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

Abstract

A power conversion device (1) is provided with an inverter (310), a drive unit (320), and a control unit (400). The drive unit (320) is provided with a switching element drive unit (340) that drives the switching elements (311a-311f) by changing the switching characteristics of the switching elements (311a-311f) provided in the inverter (310). The control unit (400) is provided with: a basic signal generation unit (410) that generates a basic signal that determines the on / off state of at least one switching element among the plurality of switching elements (311a-311f); an opening / closing characteristic setting unit (430) for generating an opening / closing characteristic setting signal for determining the opening / closing characteristic of the at least one switching element on the basis of a state quantity indicating the operating state of the power conversion device (1); and a signal transmission unit (420) that generates a control signal for operating the switching element drive unit (340) on the basis of the basic signal and the opening / closing characteristic setting signal, and transmits the control signal to the switching element drive unit (340).

Description

Technical Field

[0001] The present disclosure relates to a power conversion device, a motor drive device, and a refrigeration cycle application device that perform power conversion. Background Art

[0002] In the past, the switching speed of the switching element was changed by switching a gate resistor with a different gate resistance value to connect to the switching element. For example, Patent Document 1 discloses the following technology: in an inverter control device having an inverter main circuit with a plurality of switching elements, when the gate drive waveform of the switching element is changed, a switch is used to switch the gate resistor connected to the switching element to a gate resistor with a different gate resistance value.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-200042 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] If the technology described in the above-mentioned patent document 1 is used, the switching speed of the switching element can be changed, so that the operation can be performed in consideration of both the noise and loss generated according to the operating state of the device. However, the technology described in patent document 1 is a technology for switching the switching speed according to the gate resistance value of the gate resistor. Therefore, in order to control the noise and loss to a desired state, many resistance values ​​are required, and there is a problem that the circuit scale increases. Therefore, a technology that can suppress the increase in circuit scale and control the noise and loss to a desired state is required.

[0008] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to obtain a power conversion device capable of suppressing an increase in circuit scale and controlling noise and loss to a desired state.

[0009] Means used to solve problems

[0010] In order to solve the above problems and achieve the purpose, the power conversion device disclosed in the present invention includes an inverter having multiple switching elements, a control unit, a drive unit and a state quantity detection unit, and supplies power to a motor driving a load through the inverter. The control unit controls the operation of the inverter. The drive unit drives multiple switching elements. The state quantity detection unit detects a state quantity representing the operation state of the power conversion device. The drive unit includes a switch element drive unit that drives the switch element by changing the opening and closing characteristics of the switch element. The control unit includes a first signal generating unit, a second signal generating unit and a signal sending unit. The first signal generating unit generates a first setting signal that determines the opening and closing state of at least one switch element among the multiple switch elements. The second signal generating unit generates a second setting signal that determines the opening and closing characteristics of at least one switch element based on the state quantity. The signal sending unit generates a control signal that causes the switch element drive unit to operate based on the first setting signal and the second setting signal and sends it to the switch element drive unit.

[0011] Effects of the Invention

[0012] According to the power conversion device of the present disclosure, it is possible to suppress an increase in circuit scale and control noise and loss to a desired state. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram showing a configuration example of a power conversion device according to Embodiment 1.

[0014] Figure 2 This is a diagram showing an example of conduction Joule loss, on-state current, and on-state voltage when the opening and closing speed of the switching element of the inverter is slowed down in the power conversion device according to the first embodiment.

[0015] Figure 3 This is a diagram showing an example of conduction Joule loss, on-state current, and on-state voltage when the opening and closing speed of the switching element of the inverter is increased in the power conversion device according to the first embodiment.

[0016] Figure 4 This is a diagram showing an example of the relationship between noise and loss generated by a general switching element.

[0017] Figure 5 This is a first diagram for explaining the effect obtained by changing the opening and closing speed of the switching elements of the inverter in the power conversion device according to the first embodiment.

[0018] Figure 6 FIG. 2 is a second diagram for explaining the effect obtained by changing the opening and closing speed of the switching elements of the inverter in the power conversion device according to the first embodiment.

[0019] Figure 7 This is a diagram showing a configuration example of a switching element driving unit of the power conversion device according to the first embodiment.

[0020] Figure 8 This is a diagram showing a signal sequence of a basic signal and a switching characteristic setting signal used in the first embodiment in relation to a carrier signal.

[0021] Fig. 9 FIG. 1 is a first diagram showing a relationship between a gate current outputted from a switching element driving unit and a gate voltage indicating a rising speed of a switching element in the power conversion device according to the first embodiment.

[0022] Fig.10 The second diagram shows the relationship between the gate current outputted from the switching element driving unit and the gate voltage indicating the rising speed of the switching element in the power conversion device according to the first embodiment.

[0023] Fig.11 FIG. 3 is a third diagram showing the relationship between the gate current outputted from the switching element driving unit and the gate voltage indicating the rising speed of the switching element in the power conversion device according to the first embodiment.

[0024] Fig.12 This is a diagram showing an example of the relationship between a basic signal output by a basic signal generating unit and a gate current output by a switching element driving unit in the power conversion device according to the first embodiment.

[0025] Fig.13 This is a flowchart for explaining the operation of changing the switching characteristics of the switching element in the power conversion device according to the first embodiment.

[0026] Fig.14 This is a diagram showing an example of a hardware configuration for realizing a control unit included in the power conversion device according to the first embodiment.

[0027] Fig.15 This is a diagram showing a configuration example of a power conversion device according to the second embodiment.

[0028] Fig.16 This is a diagram showing a basic signal, a switching characteristic setting signal, and a switching characteristic switching signal used in the second embodiment in relation to a carrier signal.

[0029] Fig.17 This is a diagram showing a configuration example of a power conversion device according to a third embodiment.

[0030] Fig.18 This is a diagram showing a configuration example of a power conversion device according to a fourth embodiment.

[0031] Fig.19 This is a diagram showing a configuration example of a refrigeration cycle application device according to the fifth embodiment. DETAILED DESCRIPTION

[0032] Hereinafter, 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.

[0033] Implementation method 1.

[0034] Figure 1 1 is a diagram showing a configuration example of a power conversion device 1 according to Embodiment 1. The power conversion device 1 is connected to a commercial power source 110 and a motor 314. The power conversion device 1 converts a first AC power generated by a power supply voltage supplied from the commercial power source 110 into a second AC power having a desired amplitude and phase and supplies the second AC power to the motor 314. The commercial power source 110 is connected to a commercial power source 110 and a motor 314. Figure 1 In the example of the embodiment, a three-phase AC power supply is used, but a single-phase AC power supply may also be used. The power conversion device 1 includes a rectifier 130, state quantity detection units 501, 502, 505, 506, a capacitor 210, an inverter 310, a drive unit 320, and a control unit 400. In addition, the power conversion device 1 and the motor 314 constitute a motor drive device 2.

[0035] Rectifier 130 includes, for example, a bridge circuit composed of four rectifier elements (not shown) and a reactor. Rectifier 130 rectifies an AC voltage generated by the first AC power supplied from commercial power source 110 and converts it into DC power. Rectifier 130 may also include a step-up chopper circuit or the like.

[0036] 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, etc. In addition, the power conversion device 1 only needs to be able to supply DC power to the inverter 310, so the commercial power supply 110, the rectifier 130, and the capacitor 210 may be replaced by a DC power supply, a battery, etc.

[0037] 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, a voltage value of the DC power supplied from the capacitor 210 to the inverter 310, a current value of the DC power supplied from the capacitor 210 to the inverter 310, and the like.

[0038] The inverter 310 is a power converter connected to both ends of the capacitor 210 . The inverter 310 includes switching elements 311 a to 311 f and flyback diodes 312 a to 312 f as semiconductor elements. The switching elements 311 a to 311 f and flyback diodes 312 a to 312 f are housed in a semiconductor package 342 .

[0039] In the inverter 310, the switch elements 311a to 311f are controlled to be turned on or off by the drive unit 320 controlled by the control unit 400. The inverter 310 converts the DC power output from the rectifier 130 and the capacitor 210 into the second AC power having the desired amplitude and phase by turning the switch elements 311a to 311f on and off, that is, generates the second AC power and outputs it to the motor 314. The switch elements 311a to 311f are, for example, IGBTs (Insulated Gate Bipolar Transistors), MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), bipolar transistors, etc., but are not limited thereto. The circuit structure of the inverter 310 is not particularly limited to a three-phase bridge circuit, a single-phase bridge circuit, a half-bridge circuit, etc. In addition, the inverter 310 is not limited to a two-level three-phase bridge circuit, but may also be a two-level three-phase bridge circuit.

[0040] The driving unit 320 includes a switching element driving unit 340 that can change the switching characteristics of the switching elements 311a to 311f. The switching waveform of the switching elements 311a to 311f is one of the switching characteristics of the switching elements 311a to 311f. The switching element driving unit 340 can output two or more waveform shapes as the waveform shape of the switching waveform of the switching elements 311a to 311f. Figure 1 In the example of , the switch element driver 340 is a structure capable of changing the opening and closing characteristics of the switch elements 311a to 311f, but it is set to be capable of changing the opening and closing characteristics of at least one of the switch elements 311a to 311f. The driver 320 including the switch element driver 340 may also be a structural part located inside the inverter 310. In this case, the inverter 310 may also be a structure equipped with the switch element driver 340 for each switch element 311a to 311f. The detailed operation of the switch element driver 340 will be described later.

[0041] The state quantity detection unit 502 detects a state quantity indicating the operation state of the power conversion device 1. The state quantity detection unit 502 detects, for example, a voltage value of the second AC power supplied from the inverter 310 to the motor 314 as a load, a current value of the second AC power supplied from the inverter 310 to the motor 314 as a load, etc. The state quantity detection unit 505 detects a state quantity indicating the operation state of the power conversion device 1. The state quantity detection unit 505 detects, for example, a current value of the DC power supplied from the capacitor 210 to the inverter 310, etc. The state quantity detection unit 506 detects a state quantity indicating the operation state of the power conversion device 1. The state quantity detection unit 506 detects, for example, a current flowing to the switching elements 311b, 311d, and 311f, etc.

[0042] The control unit 400 obtains the state quantities detected by the state quantity detection units 501, 502, 505, 506 from the state quantity detection units 501, 502, 505, 506, and controls the operation of the inverter 310 based on the obtained state quantities, specifically, controls the on and off of the switching elements 311a to 311f of the inverter 310. The control unit 400 includes a basic signal generation unit 410, a signal transmission unit 420, and an opening and closing characteristic setting unit 430.

[0043] The basic signal generating unit 410 calculates a duty ratio corresponding to the state quantity detected by the state quantity detecting units 501, 502, 505, and 506. In addition, the basic signal generating unit 410 generates a basic signal S1 for controlling the operation of the switching elements 311a to 311f of the inverter 310 based on the duty ratio and the carrier signal CA. The basic signal S1 is, for example, a pulse width modulation (PWM) signal having a duty ratio corresponding to the state quantity detected by the state quantity detecting units 501, 502, 505, and 506. An example of a carrier signal is a triangular wave signal. The triangular wave signal is a periodic signal that repeats according to a carrier period that is one period of the carrier signal. The basic signal S1 generated by the basic signal generating unit 410 is a signal that determines the open / close state of at least one of the switching elements 311a to 311f, that is, whether the switching element is turned on or off. In this specification, the basic signal generator 410 is sometimes referred to as a “first signal generator” and the basic signal S1 is sometimes referred to as a “first setting signal.” The basic signal generator 410 outputs the generated basic signal S1 to the signal transmitter 420 and the switching characteristic setting unit 430 .

[0044] The switching characteristic setting unit 430 generates a switching characteristic setting signal S2 for setting the switching characteristics of the switching elements 311a to 311f when the switching characteristics of the switching elements 311a to 311f are changed by the switching element driving unit 340 of the driving unit 320. The switching characteristic setting signal S2 is set based on the state quantity detected by the state quantity detection units 501, 502, 505, and 506. The switching characteristic setting signal S2 generated by the switching characteristic setting unit 430 is a signal for determining the switching characteristics of at least one of the switching elements 311a to 311f. The carrier signal CA is referenced when the switching characteristic setting signal S2 is generated.

[0045] Specifically, when the switching elements 311a to 311f are turned on and off based on the basic signal S1 generated by the basic signal generating unit 410 for controlling the operation of the switching elements 311a to 311f of the inverter 310, the switching characteristic setting unit 430 generates a signal for controlling the magnitude of the drive signal and the timing of outputting the drive signal as the switching characteristic setting signal S2, which is used by the switching element driving unit 340 of the driving unit 320 to actually drive the switching elements 311a to 311f. In addition, in this specification, the switching characteristic setting unit 430 is sometimes described as a "second signal generating unit" and the switching characteristic setting signal S2 is sometimes described as a "second setting signal". The switching characteristic setting unit 430 outputs the generated switching characteristic setting signal S2 to the signal transmitting unit 420.

[0046] The signal transmission unit 420 generates a control signal CS for operating the switching element driver 340 based on the basic signal S1 and the switching characteristic setting signal S2, and transmits the control signal CS to the switching element driver 340. When the inverter 310 is configured to include a switching element driver 340 for each of the switching elements 311a to 311f, that is, to include six switching element drivers 340, the control unit 400 may also be configured to include a signal transmission unit 420 for each of the switching element drivers 340, that is, to include six signal transmission units 420.

[0047] In addition, Figure 1 In the example of FIG. 1 , the control unit 400 obtains the state quantity detected by the state quantity detection units 501, 502, 505, 506 from the state quantity detection units 501, 502, 505, 506, and controls the operation of the inverter 310 based on the obtained state quantity, but the present invention is not limited thereto. The control unit 400 can control the operation of the inverter 310 based on the state quantity obtained from at least one of the state quantity detection units 501, 502, 505, 506. In addition, the power conversion device 1 does not need to be operated according to the state quantity detection unit 501, 502, 505, 506. Figure 1All the state quantity detection units 501, 502, 505, and 506 are arranged in this manner. As long as the state quantity can be detected, the power conversion device 1 may include the state quantity detection unit at any position other than the position shown in the figure.

[0048] The motor 314 is a load connected to the power conversion device 1. The motor 314 is, for example, a motor for driving a compressor. The motor 314 rotates according to the amplitude and phase of the second AC power supplied from the inverter 310 to perform a compression operation. For example, in the case where the compressor is a sealed compressor, the load torque of the motor 314 that drives the compressor is mostly regarded as a constant torque load. In the motor 314, regarding the motor winding not shown in the figure, it can be a Y connection, it can be a Δ connection, and it can also be a specification that can switch between the Y connection and the Δ connection.

[0049] In addition, 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 provided in a hand dryer. In addition, the load connected to the power conversion device 1 is not limited to the motor 314, but may be a load other than the motor 314.

[0050] According to the above configuration, the power conversion device 1 of the first embodiment can change the switching characteristics of the switching elements 311a to 311f of the inverter 310 through the switching characteristics setting unit 430 and the switching element driving unit 340. Specifically, the power conversion device 1 can change the switching speed, dead time, etc. when the switching elements 311a to 311f of the inverter 310 perform the switching operation. The dead time is a short-circuit prevention period provided to prevent the switching elements 311a, 311c, 311e of the upper arm and the corresponding switching elements 311b, 311d, 311f of the lower arm from being turned on at the same time.

[0051] Figure 2 This is a diagram showing an example of conduction Joule loss, on-current, and on-voltage when the opening and closing speed of the switching elements 311 a to 311 f of the inverter 310 is slowed down in the power conversion device 1 according to the first embodiment. Figure 3 This is a diagram showing an example of conduction Joule loss, on-current, and on-voltage when the opening and closing speed of the switching elements 311 a to 311 f of the inverter 310 is increased in the power conversion device 1 according to the first embodiment.

[0052] exist Figure 2 and Figure 3 In the figure, A represents the conduction Joule loss, B represents the conduction current, and C represents the conduction voltage. Figure 2 and Figure 3In the figure, the horizontal axis represents time. For example, the on-current is the current flowing through the switch element 311a, the on-voltage is the voltage applied to both ends of the switch element 311a, and the on-joule loss is obtained by multiplying the on-current and the on-voltage. However, the measurement object is not limited to the switch element 311a, and can also be other switch elements 311b to 311f. In addition, Figure 2 and Figure 3 The difference in characteristics caused by the opening and closing speed of the switching elements 311a to 311f of the inverter 310 is shown, and the specific values ​​of "slow" and "fast" of the opening and closing speed are not particularly limited. Figure 2 and Figure 3 As shown in , by slowing down the switching speed, the noise indicated by the peak value of the on-current of B becomes smaller, but the loss indicated by the area of ​​the on-joule loss of A becomes larger. Figure 2 and Figure 3 As shown, by increasing the switching speed, the noise represented by the peak value of the on-current of B increases, but the loss represented by the area of ​​the on-joule loss of A decreases. That is, in the switching elements 311a to 311f, the generated noise and loss are in a trade-off relationship.

[0053] In the power conversion device 1, the switching element driving unit 340 is constituted by a digital gate driver. Alternatively, in the power conversion device 1, the switching elements 311a to 311f of the inverter 310 and the switching element driving unit 340 are constituted by a digital gate driver module. Thus, the power conversion device 1 can change the opening and closing 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 can control the noise and loss generated by the switching elements 311a to 311f to a desired state. In addition, the function of the opening and closing characteristic setting unit 430 in the control unit 400 can also be constituted in the digital gate driver module. In the case of this structure, the function of the existing control unit 400 can be used without modifying it.

[0054] Figure 4 1 is a diagram showing an example of the relationship between noise and loss generated by a general switching element. As described above, the noise and loss generated by a switching element are in a trade-off relationship. Therefore, in a general switching element, such as Figure 4 As shown, by increasing the switching speed, the noise increases but the loss decreases, and by decreasing the switching speed, the noise decreases but the loss increases.

[0055] Figure 51 is a first diagram for explaining the effect obtained by changing the opening and closing speed of the switching elements 311a to 311f of the inverter 310 in the power conversion device 1 of the first embodiment. Even if the power conversion device 1 is operated within the noise range specified by the product equipped with the power conversion device 1, when the load state of the motor 314 changes from a light load to a heavy load, as shown in FIG. Figure 5 As shown, the curve representing the characteristics of the noise and loss generated by the switching elements 311a to 311f also shifts to the upper right, resulting in an increase in noise. That is, in the power conversion device 1, the heavier the load, the more the noise increases. Therefore, the power conversion device 1 can reduce the noise generated by the switching elements 311a to 311f by slowing down the opening and closing speed of the switching elements 311a to 311f. Similarly, even if the power conversion device 1 is operated within the range of losses specified by the product equipped with the power conversion device 1, when the load state of the motor 314 changes from a light load to a heavy load, as shown in FIG. Figure 5 As shown, the curve representing the characteristics of noise and loss generated by the switching elements 311a to 311f also shifts to the upper right, resulting in an increase in loss. That is, in the power conversion device 1, the heavier the load, the greater the increase in loss. Therefore, the power conversion device 1 can reduce the loss generated by the switching elements 311a to 311f by increasing the opening and closing speed of the switching elements 311a to 311f.

[0056] When the load state of the motor 314 changes from a light load to a heavy load, the switching characteristic setting unit 430 changes the setting of the switching characteristics of the switching elements 311a to 311f so that the noise generated by the switching elements 311a to 311f satisfies the prescribed conditions and the loss generated by the switching elements 311a to 311f is reduced. Alternatively, when the load state of the motor 314 changes from a light load to a heavy load, the switching characteristic setting unit 430 changes the setting of the switching characteristics of the switching elements 311a to 311f so that the loss generated by the switching elements 311a to 311f satisfies the prescribed conditions and the noise generated by the switching elements 311a to 311f is reduced.

[0057] Figure 6 FIG. 2 is a diagram for explaining the effect obtained by changing the opening and closing speed of the switching elements 311a to 311f of the inverter 310 in the power conversion device 1 of the first embodiment. Specifically, the power conversion device 1 divides the on-time or off-time into two or more periods in one switching operation of the switching elements 311a to 311f, and changes the amplitude of the gate current or gate voltage for the switching elements 311a to 311f to different values ​​in each of the divided periods. The power conversion device 1 is configured as follows: Figure 6 As shown in FIG. 1 , the switching waveforms of the switching elements 311a to 311f are optimized to obtain Figure 4 The characteristics of noise and loss generated by the switching elements 311a to 311f which cannot be obtained by conventional switching elements are shown.

[0058] Next, the configuration of the switching element driving unit 340 will be described. Here, as an example, in order to simplify the description, the case where the switching element driving unit 340 changes the waveform shape of the switching waveform of one switching element 311 a will be described. Figure 7 1 is a diagram showing a configuration example of the switching element driving unit 340 of the power conversion device 1 according to the first embodiment. Figure 7 This figure also shows a configuration example of a digital gate driver composed of a switch element driver 340 and a switch element 311a. The switch element driver 340 includes n P-channel MOSFETs for conduction, namely PMOS (P-channel Metal Oxide Semiconductor), n PreDrivers for operating the n PMOS, n N-channel MOSFETs for cutoff, namely NMOS (N-channel Metal Oxide Semiconductor), and n PreDrivers for operating the n NMOS.

[0059] The switch element driver 340 is connected to the control power supply Vdd and the ground GND. The switch element driver 340 receives the control signal CS sent from the signal sending unit 420. The switch element driver 340 changes the number of PMOS or NMOS operating in the switch element driver 340 based on the control signal CS. Thus, the switch element driver 340 can change the gate current I as the drive signal output to the switch element 311a during each period of the on period and the off period. G The amplitude value of is changed to n types to adjust the opening and closing speed of the switch element 311a. The more the number of PMOS or NMOS in operation is increased in the switch element driving unit 340, the greater the gate current I output to the switch element 311a can be. G The greater the absolute value of the gate current I, the faster the switching speed of the switch element 311a can be. In addition, for the switch element driver 340, the more PMOS and NMOS are provided inside, the more precise the switching speed of the switch element 311a can be adjusted. G The faster the response to the increase or decrease of I, the more precise the gate current I can be adjusted during one switching period. GThe control signal CS from the signal transmission unit 420 can be either an analog signal or a digital signal as long as it can change the number of PMOS or NMOS operating in the switch element driving unit 340. Figure 7 In the example shown in FIG. 1 , m control signals CS are connected in parallel from the signal transmission unit 420 to the switch element driving unit 340. However, this is an example, and the number of control signals CS is not limited to m. The number of control signals CS may be a number that can indicate whether each PMOS and each NMOS can operate. If the control signal indicates a voltage or the like by an analog signal, the number may be 1.

[0060] Next, the basic signal S1 generated by the basic signal generating unit 410 and the switching characteristic setting signal S2 generated by the switching characteristic setting unit 430 are described. Here, as with the switching element driving unit 340, the case where the switching element driving unit 340 changes the waveform shape of the switching waveform of one switching element 311a is described as an example. Figure 8 This is a diagram showing the signal sequence of the basic signal S1 and the switching characteristic setting signal S2 used in the first embodiment in relation to the carrier signal. Figure 8 In the upper part of FIG, a triangular wave signal is shown as an example of a carrier signal. Figure 8 The middle part of FIG. 1 shows a PWM signal as an example of a basic signal S1 that determines the on / off state of the switching element 311 a. Figure 8 The lower layer of shows the switching characteristic setting signal S2 that determines the switching characteristic of the switching element 311a. Figure 8 The lower layer portion of shows the switching characteristic setting signal S2 in a simplified manner, but it is assumed that a serial signal of a plurality of bits is transmitted during the period indicated by one pulse.

[0061] exist Figure 8 In the example, the basic signal S1 is generated based on the timing of the valley at the bottom of the triangular wave signal. The data length of the basic signal S1 is a fixed length and is generated in microseconds. One cycle of the basic signal S1 is, for example, 10μs to 1ms. In this example, the basic signal S1 is sent to the signal sending unit 420 with a data length of 10μs to 1ms in each cycle of 10μs to 1ms.

[0062] On the other hand, the switching characteristic setting signal S2 is generated based on the timing of the peak at the top of the triangular wave signal. The data length of the switching characteristic setting signal S2 is a variable length. In addition, the switching characteristic setting signal S2 is a signal generated every time the switching characteristic needs to be changed, that is, a signal generated irregularly. As described above, in this specification, the switching characteristic setting signal S2 assumes a serial signal of multiple bits. To give a specific example, when a pulse signal with a width of 100μs of 48 bits is sent during 1 cycle, the data length of the switching characteristic setting signal S2 becomes 4.8ms. If at least 10 bits of information are sent, the data length becomes more than 1ms. Therefore, the switching characteristic setting signal S2 is generated in milliseconds and sent to the signal sending unit 420.

[0063] In the first embodiment, when the signal transmission unit 420 does not receive the switching characteristic setting signal S2, it generates the control signal CS using only the basic signal S1 and transmits the generated control signal CS to the switching element driving unit 340. In addition, in the first embodiment, when the signal transmission unit 420 receives the switching characteristic setting signal S2, after the reception of the switching characteristic setting signal S2 is completed, it generates the control signal CS based on both the basic signal S1 and the switching characteristic setting signal S2 and transmits it to the switching element driving unit 340. In this way, the switching elements 311a to 311f of the inverter 310 can be stably driven. In addition, the switching characteristics of the switching elements 311a to 311f can be quickly changed by the control signal CS reflecting the switching characteristic setting signal S2, so even if the load of the device connected to the motor 314 changes, the load change can be quickly suppressed.

[0064] In addition, in the above description, the case where the basic signal S1 is generated based on the timing of the valley of the triangular wave signal and the switching characteristic setting signal S2 is generated based on the timing of the peak of the triangular wave signal is described, but the present invention is not limited thereto. The basic signal S1 may be generated based on the timing of the peak of the triangular wave signal and the switching characteristic setting signal S2 may be generated based on the timing of the valley of the triangular wave signal.

[0065] Fig. 9 1 is a graph showing the gate current I outputted by the switching element driving unit 340 in the power conversion device 1 according to the first embodiment. G The gate voltage V G Figure 1 of the relationship. Fig.10 1 is a graph showing the gate current I outputted by the switching element driving unit 340 in the power conversion device 1 according to the first embodiment. G The gate voltage V G The second figure of the relationship. Fig. 9 and Fig.10 As shown, the switching element driving unit 340 increases the output gate current I G , the faster the gate voltage V G The higher the value, the faster the opening and closing speed of the switch element 311a can be made. Fig. 9 and Fig.10 As shown, the switching element driving unit 340 reduces the output gate current I G , the more it can slow down the gate voltage V G The higher the value, the slower the opening and closing speed of the switch element 311a. Figure 4 As shown, the power conversion device 1 can reduce the output gate current I when it is desired to reduce the noise generated by the switching element 311a. G By slowing down the switching speed, when it is desired to reduce the loss caused by the switching element 311a, the output gate current I can be increased. G This makes the opening and closing speed faster. Fig. 9 and Fig.10 The gate current I G and gate voltage V G The waveform is an ideal example, Figure 2 and Figure 3 As shown, in fact, the gate current I G It takes time for the current to become a constant value.

[0066] Fig.11 1 is a graph showing the gate current I outputted by the switching element driving unit 340 in the power conversion device 1 according to the first embodiment. G The gate voltage V G Figure 3 of the relationship. Fig.11 As shown, the switch element driving unit 340 can divide the conduction period and change the gate current I G That is, the switching element driving unit 340 can finely adjust the gate current I within one conduction period. G Therefore, the same gate current I as that output during the on-time is G Compared with the case of Figure 6 As shown, control is performed to reduce the noise generated by the switching element 311a and reduce the loss generated by the switching element 311a.

[0067] use Figures 9 to 11 , the on-period of the switch element 311a is described as an example, but the off-period of the switch element 311a is the same. Fig.121 and 2 show the relationship between the basic signal S1 outputted by the basic signal generating unit 410 and the gate current I outputted by the switching element driving unit 340 in the power conversion device 1 according to the first embodiment. G The following is an example of a relationship between . Fig.12 In the on-period of the switching element 311a, the switching element driving unit 340 outputs the gate current I G During the period of division, the gate current I with a large amplitude current Ig2 can be output at the beginning. G Then, the gate current I with a small amplitude Ig1 is output. G , it is also possible to output a gate current I with a small amplitude of current Ig1 at the beginning G Then, the gate current I with a large amplitude Ig2 is output. G Similarly, the switching element driving unit 340 outputs a gate current I during the off period of the switching element 311a. G The gate current I with a large amplitude of -Ig2 can be output from the beginning. G Then the gate current I with a small amplitude of -Ig1 is output. G , it is also possible to output a gate current I with a small amplitude of -Ig1 at the beginning G Then the gate current I with a large current amplitude -Ig2 is output. G .

[0068] In this way, the switch element driving unit 340 can divide at least one of the on-period and off-period of the switch element 311a into two or more periods based on the on-period set by the on-period setting unit 430, and set the gate current I G The amplitude of the gate current I is changed to a different size. In addition, the switching element driving unit 340 includes a plurality of transistors, and the number of transistors to be operated is changed based on the switching characteristics set by the switching characteristics setting unit 430, thereby changing the gate current I G Amplitude.

[0069] In addition, the switching element driving unit 340 can change the gate current I G The switching element driving unit 340 can change to a different switching characteristic for each switching cycle of the switching element 311a during the operation of the power conversion device 1. In this case, the switching characteristic setting unit 430 can change the setting of the switching characteristic of the switching element 311a according to the same cycle as the switching cycle of the switching element 311a. The switching characteristic setting unit 430 can also change the setting of the switching characteristic of the switching element 311a according to a cycle that is a positive integer multiple of the switching cycle of the switching element 311a.

[0070] In addition, regarding the structure of the switching element driving unit 340, Figure 7 The structure of the switching element driving unit 340 shown is an example and is not limited thereto. Regarding the MOS (Metal Oxide Semiconductor) used internally, the switching element driving unit 340 may use transistors other than MOS.

[0071] The switch element driver 340 can adjust the opening and closing speed of the switch element 311a more finely by digital control based on multiple MOS, compared with the analog control of physically switching the gate resistor described in Patent Document 1. In addition, the resistance value of the gate resistor changes according to the temperature, so the accuracy of the temperature change sometimes becomes a problem. In contrast, in the digital gate driver, such a problem does not occur. Therefore, the switch element driver 340 composed of the digital gate driver can adjust the opening and closing speed with high accuracy.

[0072] In addition, in the above example, the switch element driving unit 340 changes the number of PMOS or NMOS to be operated according to the obtained control signal CS, and increases the gate current I corresponding to the number of PMOS or NMOS to be operated. G The switching element driving unit 340 may also pre-store the gate current I corresponding to the control signal CS. G The gate current I is output according to the output pattern corresponding to the obtained control signal CS. G In addition, the switching element driving unit 340 may also pre-store the control signal CS obtained in the past and the gate current I when the control signal CS was obtained in the past. G When the same control signal CS is obtained, the gate current I is output according to the stored output pattern. G The switch element driving unit 340 stores the gate current I corresponding to the control signal CS in advance. G output style, which can reduce the output gate current I G processing load at the time.

[0073] In addition, regarding the switching element driving unit 340, in the above example, the gate current I is changed as the driving signal output to the switching element 311a. G , to adjust the switching speed of the switch element 311a and change the switching characteristics of the switch element 311a, but the present invention is not limited thereto. The switch element driving unit 340 can set the driving signal output to the switch element 311a to be the gate voltage V G , by changing the gate voltage V G, similarly, the opening and closing speed of the switch element 311a is adjusted to change the opening and closing characteristics of the switch element 311a.

[0074] In this way, the switch element driving unit 340 can divide at least one of the on-period and off-period of the switch element 311a into two or more periods based on the on-period set by the on-period setting unit 430, and set the gate voltage V for the switch element 311a to 100V in each of the divided periods. G The amplitude of the switching element is changed to a different size. In addition, the switching element driving unit 340 includes a plurality of transistors, and the number of transistors to be operated is changed based on the switching characteristics set by the switching characteristics setting unit 430, thereby being able to change the gate voltage V G Amplitude.

[0075] In addition, the switch element driving unit 340 may also adjust the dead time set in the opening and closing action of the switch elements 311a to 311f when controlling the above-mentioned opening and closing speed. Specifically, when the opening and closing speed is changed, in the case where the opening and closing speed after the change is set to be faster than the opening and closing speed before the change, the switch element driving unit 340 sets the dead time after the change to be shorter than the dead time before the change. In addition, in the case where the opening and closing speed after the change is set to be slower than the opening and closing speed before the change, the switch element driving unit 340 sets the dead time after the change to be longer than the dead time before the change. In this way, the dead time can be appropriately adjusted, and therefore, the influence of the voltage error caused by the dead time can be reduced.

[0076] Fig.13 This is a flowchart for explaining the operation of changing the switching characteristics of the switching elements 311a to 311f in the power conversion device 1 of the first embodiment. In the power conversion device 1, the basic signal generation unit 410 generates a basic signal S1 for driving the switching elements 311a to 311f of the inverter 310 based on the state quantity obtained from the state quantity detection units 501, 502, 505, and 506 (step S1). In this way, in the control unit 400, the basic signal generation unit 410 generates the basic signal S1 based on the state quantity obtained from the state quantity detection units 501, 502, 505, and 506, and determines the timing of turning on the switching elements 311a to 311f and the timing of turning off the switching elements 311a to 311f. The basic signal generation unit 410 outputs the generated basic signal S1 to the switching characteristic setting unit 430.

[0077] The switching characteristic setting unit 430 generates a switching characteristic setting signal S2 for setting the switching characteristics of the switching elements 311a to 311f of the inverter 310 based on the basic signal S1 obtained from the basic signal generating unit 410 and the state quantities obtained from the state quantity detecting units 501, 502, 505, and 506 (step S2). In the switching characteristic setting signal S2, the switching characteristics of the timing of turning on the switching elements 311a to 311f and the timing of turning off the switching elements 311a to 311f determined by the basic signal S1 are set.

[0078] The signal transmission unit 420 generates a control signal CS for operating the switch element driver 340 based on the basic signal S1 and the switch characteristic setting signal S2 (step S3). The control signal CS generated by the signal transmission unit 420 is transmitted to the switch element driver 340. The switch element driver 340 changes the switch characteristics of the switch elements 311a to 311f based on the control signal CS obtained from the signal transmission unit 420 (step S4).

[0079] As described above, the power conversion device 1 of embodiment 1 can change the switching characteristics of the switching elements 311a to 311f when driving the switching elements 311a to 311f of the inverter 310 by utilizing the functions of the basic signal generating unit 410, the signal transmitting unit 420 and the switching characteristic setting unit 430.

[0080] Next, the hardware configuration of the control unit 400 included in the power conversion device 1 will be described. Fig.14 1 is a diagram showing an example of a hardware configuration for realizing the control unit 400 included in the power conversion device 1 according to Embodiment 1. The control unit 400 is realized by a processor 91 and a memory 92 .

[0081] The processor 91 is a CPU (also called a Central Processing Unit, a central processing device, a processing device, an arithmetic device, a microprocessor, a microcomputer, a processor, a DSP (Digital Signal Processor), or a system LSI (Large Scale Integration). The memory 92 can be exemplified by a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable ROM), or an EEPROM (registered trademark) (Electrically EPROM). In addition, the memory 92 is not limited thereto, and may be a magnetic disk, an optical disk, a high-density disk, a mini disk, or a DVD (Digital Versatile Disc).

[0082] As described above, according to the power conversion device of embodiment 1, the control unit controls the operation of the inverter, and the drive unit drives the multiple switching elements provided by the inverter. The drive unit includes a switch element drive unit that changes the opening and closing characteristics of the switch element to drive the switch element. The control unit includes a first signal generating unit, a second signal generating unit, and a signal sending unit. The first signal generating unit generates a first setting signal that determines the opening and closing state of at least one switch element among the multiple switch elements. The second signal generating unit generates a second setting signal that determines the opening and closing characteristics of at least one switch element based on the state quantity. The signal sending unit generates a control signal that causes the switch element drive unit to operate based on the first setting signal and the second setting signal and sends it to the switch element drive unit. As a result, the power conversion device can suppress the increase in circuit scale and change the opening and closing characteristics of the switch element.

[0083] In addition, in the power conversion device of the first embodiment, the switch element driving unit is configured to be able to divide at least one of the on-period and off-period of the switch element into two or more periods based on the on-off characteristics set by the on-off characteristics setting signal, and change the amplitude of the gate current or gate voltage for the switch element to different sizes in each of the divided periods. According to the power conversion device configured in this way, the gate current or gate voltage output to the switch element can be finely adjusted within one switching period, and the on-off characteristics that cannot be achieved by the method of patent document 1 and the like can be realized. As a result, it is possible to suppress the increase in circuit scale and control noise and loss to a desired state.

[0084] In addition, in the power conversion device of the first embodiment, when the signal transmission unit does not receive the second setting signal, it generates the control signal using only the first setting signal, and when the second setting signal is received, after the second setting signal is received, it generates the control signal using both the first setting signal and the second setting signal. As a result, the second setting signal that has been received is quickly reflected in the control of the switching characteristics. Thus, the load fluctuation generated by the power conversion device can be quickly suppressed.

[0085] Implementation method 2.

[0086] Fig.15 1A is a diagram showing a configuration example of a power conversion device 1A according to Embodiment 2. In Embodiment 2, the power conversion device 1A and the motor 314 constitute a motor drive device 2A. Figure 1 In the structure of , the driving unit 320 is replaced by the driving unit 320A, the control unit 400 is replaced by the control unit 400A, and the signal sending unit 420 is replaced by the signal sending unit 420A. Fig.15 A signal receiving unit 350 is added to the driving unit 320A. Figure 1 The power conversion device 1 shown is the same or equivalent, and the same reference numerals are given to the same or equivalent components, and duplicate description is omitted.

[0087] The signal sending unit 420A sends the basic signal S1 sent from the basic signal generating unit 410 to the signal receiving unit 350 of the driving unit 320A. The transmission of the basic signal S1 can be parallel transmission or serial transmission. In addition, the signal sending unit 420A sends the switching characteristic setting signal S2 sent from the switching characteristic setting unit 430 to the signal receiving unit 350 of the driving unit 320A. In embodiment 2, the transmission of the switching characteristic setting signal S2 is performed by serial transmission. Any synchronization method can also be used for synchronization in serial transmission. As representative synchronization methods, there are a start-stop synchronization method, an independent synchronization method, a frame synchronization method, etc.

[0088] Fig.16 This is a diagram showing the basic signal S1, the switching characteristic setting signal S2, and the switching characteristic switching signal used in the second embodiment in relation to the carrier signal. Fig.16 In the upper part of FIG, a triangular wave signal is shown as an example of a carrier signal. Fig.16 The upper middle portion of FIG. 1 shows a PWM signal as an example of a basic signal S1 that determines the on / off state of the switching element 311 a. Fig.16The lower middle portion of FIG. 1 shows a switching characteristic setting signal S2 that determines the switching characteristics of the switching element 311a. These triangular wave signals, the basic signal S1, and the switching characteristic setting signal S2 are basically the same as those described in Embodiment 1. Fig.16 The lower layer of shows the switching characteristic switching signal. The switching characteristic switching signal is superimposed on the switching characteristic setting signal S2 and transmitted to the signal receiving unit 350 of the driving unit 320A.

[0089] The switching characteristic switching signal is a timing signal that specifies the switching timing for switching the switching characteristics of the switch elements 311a to 311f. That is, in the second embodiment, the switching characteristic setting signal S2 includes a timing signal that specifies the timing for switching the switching characteristics of the switch elements 311a to 311f.

[0090] Therefore, in the control of the second embodiment, the switching characteristics of the plurality of switching elements can be changed simultaneously at a timing when none of the plurality of switching elements performs a switching operation. Such control is useful in applications where the number of switching elements is large, such as inverter driving of a three-phase motor. If the switching characteristics of the plurality of switching elements are changed simultaneously, the load can be driven stably.

[0091] As described above, according to the power conversion device of the second embodiment, the control unit controls the operation of the inverter, and the drive unit drives the plurality of switching elements provided by the inverter. The control unit includes a first signal generating unit, a second signal generating unit, and a signal transmitting unit. The drive unit includes a switching element driving unit and a signal receiving unit. The first signal generating unit generates a first setting signal that determines the switching state of at least one switching element among the plurality of switching elements. The second signal generating unit generates a second setting signal that determines the switching characteristics of at least one switching element based on the state quantity. The signal transmitting unit transmits the first setting signal and the second setting signal to the drive unit. The signal receiving unit generates a control signal CS that causes the switching element driving unit to operate based on the first setting signal and the second setting signal received from the control unit. The switching element driving unit changes the switching characteristics of the switching element based on the control signal CS. Thus, the power conversion device can suppress the increase in circuit scale and change the switching characteristics of the switching element including the switching speed. In addition, the power conversion device can change the switching characteristics of a plurality of switching elements at the same time, so that even if the switching characteristics are changed, the load can be driven stably.

[0092] Implementation method 3.

[0093] Fig.17 1B is a diagram showing a configuration example of a power conversion device 1B according to a third embodiment. In the third embodiment, the power conversion device 1B and the motor 314 constitute a motor drive device 2B. Fig.15In the structure of , the drive unit 320A is replaced by the drive unit 320B. Fig.17 In the driving unit 320B of the embodiment, a noise suppression unit 360 is added to the input side of the signal receiving unit 350. Fig.15 The power conversion device 1A shown is the same or equivalent, and the same reference numerals are given to the same or equivalent components, and duplicate description is omitted.

[0094] The noise suppression unit 360 suppresses the high-frequency noise contained in the switching characteristic setting signal S2. An example of the noise suppression unit 360 is a low-pass filter. The low-pass filter can be composed of an RC filter based on a resistor and a capacitor. In addition, the low-pass filter can also be composed of only a capacitor. As described above, when the switching speed of the switching elements 311a to 311f is fast, the noise becomes larger. Therefore, when the signal receiving unit 350 is located near the semiconductor package 342 or is provided inside the semiconductor package 342, high-frequency noise is easily superimposed on the switching characteristic setting signal S2 received by the signal receiving unit 350. Therefore, in embodiment 3, the high-frequency noise that may be contained in the switching characteristic setting signal S2 is suppressed by the noise suppression unit 360. As a result, the switching characteristics of the switching elements 311a to 311f can be prevented from being erroneously changed. This effect is particularly useful when the switching elements 311a to 311f are power semiconductor elements to which a high voltage is applied.

[0095] In the third embodiment, only the switching characteristic setting signal S2 is passed through the noise suppression unit 360, but the present invention is not limited thereto. The basic signal S1 may be received by the signal receiving unit 350 after passing through the noise suppression unit.

[0096] As described above, according to the power conversion device of the third embodiment, in the structure of the second embodiment, the driving unit includes a noise suppression unit that suppresses high-frequency noise, and the signal receiving unit receives at least one of the first setting signal and the second setting signal transmitted from the signal transmitting unit via the noise suppression unit. Thus, it is possible to suppress high-frequency noise that may be superimposed on the basic signal S1 or the switching characteristic setting signal S2, thereby preventing the switching characteristics of the switching element from being erroneously changed.

[0097] Implementation method 4.

[0098] Fig.18 1C is a diagram showing a configuration example of a power conversion device 1C according to a fourth embodiment. In the fourth embodiment, the power conversion device 1C and the motor 314 constitute a motor drive device 2C. Fig.17 In the structure of , the driving unit 320B is replaced by the driving unit 320C, and the control unit 400A is replaced by the control unit 400C. Fig.18In the driving unit 320C, the signal receiving unit 350 is replaced by a signal transceiver unit 350C. Fig.18 In the control unit 400C, the signal sending unit 420A is replaced by the signal transceiver unit 420C. Fig.17 The same or equivalent components are denoted by the same reference numerals and duplicate descriptions are omitted. In addition, in this specification, the signal transceiver 420C is sometimes described as a "first transceiver" and the signal transceiver 350C is sometimes described as a "second transceiver".

[0099] The signal transceiver 350C has the functions of the signal receiving unit 350 described above, and further generates an implementation signal CV indicating that the change control of the switching characteristics has been implemented, and transmits it to the signal transceiver 420C of the control unit 400C. The control unit 400C receives the implementation signal CV through the signal transceiver 420C, and can grasp the situation that the switching characteristics of the switching elements 311a to 311f have been changed. That is, the control unit 400C can grasp the operating conditions of the switching element driving unit 340 and the signal transceiver 350C based on the implementation signal CV.

[0100] In the fourth embodiment, the structure in which the transmission function is added to the drive unit side and the reception function is added to the control unit side is applied to Fig.17 The structure of the third embodiment shown in FIG. Fig.15 The structure of embodiment 2 is shown.

[0101] As described above, according to the power conversion device of the fourth embodiment, in the structure of the second and third embodiments, the control unit includes a first signal transceiver unit, which sends the first setting signal and the second setting signal to the drive unit, and receives an implementation signal indicating that the switching element has been subjected to a change control of the switching characteristic from the drive unit. In addition, the drive unit includes a second signal transceiver unit, which generates a control signal for causing the switching element drive unit to operate based on the first setting signal and the second setting signal received from the control unit, and sends an implementation signal to the control unit when the switching element has been subjected to a change control of the switching characteristic. Thus, the control unit can grasp the operation status of the drive unit.

[0102] Implementation method 5.

[0103] Fig.19Refrigeration cycle application device 900 of Embodiment 5 is a diagram showing a structural example. Refrigeration cycle application device 900 of Embodiment 5 includes power conversion device 1 described in Embodiment 1. Refrigeration cycle application device 900 of Embodiment 5 can also include power conversion devices 1A to 1C described in Embodiments 2 to 4. Refrigeration cycle application device 900 of Embodiment 5 can be applied to products including refrigeration cycles, such as air conditioners, refrigerators, freezers, and heat pump water heaters. Fig.19 In the drawings, components having the same functions as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

[0104] The refrigeration cycle application equipment 900 is equipped with the compressor 315 having the motor 314 built therein, the four-way valve 902 , the indoor heat exchanger 906 , the expansion valve 908 , and the outdoor heat exchanger 910 in the first embodiment via a refrigerant pipe 912 .

[0105] A compression mechanism 904 for compressing the refrigerant and a motor 314 for operating the compression mechanism 904 are provided inside the compressor 315 .

[0106] The refrigeration cycle application device 900 can perform heating operation or cooling operation by switching the four-way valve 902. The compression mechanism 904 is driven by the motor 314 which is subjected to variable speed control.

[0107] During heating operation, as shown by the solid arrow, the refrigerant is pressurized by the compression mechanism 904 and then sent out, and returns to the compression mechanism 904 through the four-way valve 902, the indoor heat exchanger 906, the expansion valve 908, the outdoor heat exchanger 910 and the four-way valve 902.

[0108] During cooling operation, as shown by the dotted arrow, the refrigerant is pressurized by the compression mechanism 904 and then sent out, and returns to the compression mechanism 904 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.

[0109] During heating operation, the indoor heat exchanger 906 functions as a condenser to release heat, and the outdoor heat exchanger 910 functions as an evaporator to absorb heat. During cooling operation, the outdoor heat exchanger 910 functions as a condenser to release heat, and the indoor heat exchanger 906 functions as an evaporator to absorb heat. The expansion valve 908 decompresses the refrigerant and expands it.

[0110] In addition, regarding the refrigeration cycle application device 900, even if it is operated within the specified noise range, when the load state of the motor 314 changes from a light load to a heavy load, such as Figure 5As shown in FIG. 1 , the curve representing the characteristics of noise and loss generated by the switching elements 311a to 311f and the like also shifts to the upper right, resulting in an increase in noise. Therefore, the refrigeration cycle application device 900 can reduce the noise generated by the switching elements 311a to 311f and the like by slowing down the opening and closing speed of the switching elements 311a to 311f and the like. Similarly, with respect to the refrigeration cycle application device 900, even if the operation is within the prescribed loss range, when the load state of the motor 314 changes from a light load to a heavy load, as shown in FIG. Figure 5 As shown, the curve representing the characteristics of noise and loss generated by the switching elements 311a to 311f and the like also shifts to the upper right, resulting in an increase in loss. Therefore, the refrigeration cycle application device 900 can reduce the loss generated by the switching elements 311a to 311f and the like by increasing the opening and closing speed of the switching elements 311a to 311f and the like.

[0111] Here, in the power conversion device 1 provided in the refrigeration cycle application device 900, when the digital gate driver composed of the switching element driving unit 340 and the switching elements 311a to 311f included in the driving unit 320 opens and closes quickly, the surge voltage increases and a large amount of electromagnetic noise is generated. When the refrigeration cycle application device 900 uses a refrigerant with flammability, when the refrigerant leaks, it may burn due to discharge caused by electromagnetic noise. Therefore, the refrigeration cycle application device 900 sets the opening and closing speed of the digital gate driver provided in the power conversion device 1 according to the flammability of the refrigerant used by the refrigeration cycle application device 900. For example, the higher the flammability of the refrigerant used by the refrigeration cycle application device 900, the slower the opening and closing speed of the digital gate driver provided in the power conversion device 1 by the refrigeration cycle application device 900. The refrigeration cycle application device 900 can reduce the surge voltage by slowing down the opening and closing speed of the digital gate driver and suppress the generation of discharge caused by electromagnetic noise, thereby preventing combustion even if the refrigerant leaks from the refrigeration cycle application device 900.

[0112] The refrigerant used in the refrigeration cycle application equipment 900 is, for example, R1234yf, R1234ze(E), R1243zf, HFO1123, HFO1132(E), R1132a, CF3I, R290, R463A, R466A, R454A, R454B, R454C, etc.

[0113] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, the embodiments may be combined with each other, and some configurations may be omitted or modified without departing from the spirit and scope of the invention.

[0114] Description of Reference Numerals

[0115] 1, 1A, 1B, 1C power conversion device, 2, 2A, 2B, 2C motor drive device, 91 processor, 92 memory, 110 commercial power supply, 130 rectifier, 210 capacitor, 310 inverter, 311a to 311f switching element, 312a to 312f freewheeling diode, 314 motor, 315 compressor, 320, 320A, 320B, 320C drive unit, 340 switch element drive unit, 342 semiconductor package, 350 signal connection receiving unit, 350C, 420C signal receiving and transmitting unit, 360 noise suppression unit, 400, 400A, 400C control unit, 410 basic signal generating unit, 420, 420A signal sending unit, 430 opening and closing characteristic setting unit, 501, 502, 505, 506 state quantity detection unit, 900 refrigeration cycle application equipment, 902 four-way valve, 904 compression mechanism, 906 indoor heat exchanger, 908 expansion valve, 910 outdoor heat exchanger, 912 refrigerant piping.

Claims

1. A power conversion device comprising an inverter having a plurality of switching elements, a control unit for controlling the operation of the inverter, and a drive unit for driving the plurality of switching elements, wherein power is supplied to a motor driving a load through the inverter, wherein: The power conversion device includes a state quantity detection unit that detects a state quantity indicating an operating state of the power conversion device. The driving unit includes a switching element driving unit that changes the switching characteristics of the switching element to drive the switching element. The control unit comprises: a first signal generating unit for generating a first setting signal for determining an open / close state of at least one switching element among the plurality of switching elements; a second signal generating unit for generating a second setting signal for determining the switching characteristics of the at least one switching element based on the state quantity; as well as A signal transmission unit generates a control signal for operating the switching element driving unit based on the first setting signal and the second setting signal, and transmits the control signal to the switching element driving unit.

2. The power conversion device according to claim 1, wherein: The first setting signal is a pulse width modulation signal, The second setting signal is a serial signal.

3. The power conversion device according to claim 1 or 2, wherein: When the signal transmission unit does not receive the second setting signal, the signal transmission unit generates the control signal using only the first setting signal. When the signal transmission unit receives the second setting signal, the signal transmission unit generates the control signal using both the first setting signal and the second setting signal after reception of the second setting signal is completed.

4. A power conversion device comprising an inverter having a plurality of switching elements, a control unit for controlling the operation of the inverter, and a drive unit for driving the plurality of switching elements, wherein power is supplied to a motor driving a load through the inverter, wherein: The power conversion device includes a state quantity detection unit that detects a state quantity indicating an operating state of the power conversion device. The control unit comprises: a first signal generating unit for generating a first setting signal for determining an open / close state of at least one switching element among the plurality of switching elements; a second signal generating unit for generating a second setting signal for determining the switching characteristics of the at least one switching element based on the state quantity; and a signal sending unit that sends the first setting signal and the second setting signal to the driving unit, The driving unit comprises: a switching element driving unit that changes the switching characteristics of the switching element; and A signal receiving unit generates a control signal for operating the switching element driving unit based on the first setting signal and the second setting signal received from the control unit.

5. The power conversion device according to claim 4, wherein: The second setting signal includes a timing signal that specifies a timing for switching the opening and closing characteristics of the switching element.

6. The power conversion device according to claim 4 or 5, wherein: The driving unit includes a noise suppressing unit for suppressing high frequency noise. The signal receiving unit receives at least one of the first setting signal and the second setting signal transmitted from the signal transmitting unit via the noise suppressing unit.

7. A power conversion device comprising an inverter having a plurality of switching elements, a control unit for controlling the operation of the inverter, and a drive unit for driving the plurality of switching elements, wherein power is supplied to a motor driving a load through the inverter, wherein: The power conversion device includes a state quantity detection unit that detects a state quantity indicating an operating state of the power conversion device. The control unit comprises: a first signal generating unit for generating a first setting signal for determining an open / close state of at least one switching element among the plurality of switching elements; a second signal generating unit for generating a second setting signal for determining the switching characteristics of the at least one switching element based on the state quantity; as well as a first signal transceiver that transmits the first setting signal and the second setting signal to the drive unit, and receives from the drive unit an implementation signal indicating that the switching characteristic change control is implemented on the switching element, The driving unit comprises: a switching element driving unit that changes the switching characteristics of the switching element; and A second signal transceiver generates a control signal for causing the switch element driving unit to operate based on the first setting signal and the second setting signal received from the control unit, and sends the implementation signal to the control unit when the switch element is controlled to change the opening and closing characteristics.

8. The power conversion device according to claim 7, wherein: The second setting signal includes a timing signal that specifies a timing for switching the opening and closing characteristics of the switching element.

9. The power conversion device according to claim 7 or 8, wherein: The driving unit includes a noise suppressing unit for suppressing high frequency noise. The second signal transceiver receives at least one of the first setting signal and the second setting signal transmitted from the first signal transceiver via the noise suppression unit.

10. The power conversion device according to any one of claims 1 to 9, wherein: The switching element driving unit is configured to divide at least one of the on-period and off-period of the switching element into two or more periods based on the opening and closing characteristics set by the second setting signal, and to change the amplitude of the gate current or gate voltage of the switching element to different sizes in each of the divided periods.

11. The power conversion device according to claim 10, wherein: The switching characteristics are the switching speed and dead time of the switching element. When the opening / closing speed after the change is set faster than the opening / closing speed before the change, the dead time after the change is set shorter than the dead time before the change, When the opening / closing speed after the change is set to be slower than the opening / closing speed before the change, the dead time after the change is set to be longer than the dead time before the change.

12. The power conversion device according to any one of claims 1 to 11, wherein: The data length of the first setting signal is a fixed length. The data length of the second setting signal is a variable length.

13. The power conversion device according to claim 12, wherein: The first setting signal is generated in microseconds. The second setting signal is generated in millisecond order.

14. A motor drive device, wherein: The motor drive device includes the power conversion device according to any one of claims 1 to 13.

15. A refrigeration cycle application device, wherein: The refrigeration cycle application equipment includes the power conversion device according to any one of claims 1 to 13.

16. The refrigeration cycle application device according to claim 15, wherein: The refrigerant used in the refrigeration cycle application equipment is any refrigerant selected from R1234yf, R1234ze(E), R1243zf, HFO1123, HFO1132(E), R1132a, CF3I, R290, R463A, R466A, R454A, R454B, and R454C.

17. The refrigeration cycle application device according to claim 16, wherein: The opening and closing speed of the digital gate driver included in the power conversion device is set according to the combustibility of the refrigerant.

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