Power conversion equipment and refrigeration cycle application equipment

Abstract

A power conversion device (1) comprises an inverter (310), a drive unit (320), and a control unit (400). The drive unit (320) comprises a switching element drive unit (340) that alters the opening / closing characteristics of switching elements (311a–311f) of the inverter (310) and drives the switching elements (311a–311f). The control unit (400) comprises a base signal generation unit (410) that generates a base signal that sets the open / closed state of at least one switching element from among the plurality of switching elements (311a–311f), an opening / closing characteristics setting unit (430) that generates an opening / closing characteristics setting signal that sets the opening / closing characteristics of at least one switching element in accordance with a state quantity that indicates 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 base signal and the opening / closing characteristics setting signal and transmits the control signal to the switching element drive unit (340).

Description

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

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

[0002] Conventionally, the opening and closing speed of a switching element has been changed by switching between gate resistors having different gate resistance values ​​and connecting them to the switching element. For example, Patent Document 1 discloses a technique for an inverter control device including an inverter main circuit having a plurality of switching elements, in which, when changing the gate drive waveform of the switching element, the gate resistor connected to the switching element is switched to a gate resistor having a different gate resistance value using a switch.

[0003] Japanese Patent Application Laid-Open No. 2012-200042

[0004] The technology described in Patent Document 1 makes it possible to change the switching speed of a switching element, thereby enabling operation that takes into account both noise and loss generated depending on the operating state of the device. However, the technology described in Patent Document 1 switches the switching speed depending on the gate resistance value of a gate resistor, which requires a large resistance value to control noise and loss to desired states, resulting in an increase in circuit size. Therefore, there is a need for a technology that can control noise and loss to desired states while suppressing an increase in circuit size.

[0005] The present disclosure has been made in view of the above, and has an object to provide a power conversion device that can control noise and loss to desired states while suppressing an increase in circuit size.

[0006] In order to solve the above-mentioned problems and achieve the object, a power conversion device according to the present disclosure includes an inverter having a plurality of switching elements, a control unit, a drive unit, and a state quantity detection unit, and supplies power to a motor that drives a load via the inverter. The control unit controls the operation of the inverter. The drive unit drives the plurality of switching elements. The state quantity detection unit detects state quantities that indicate the operating state of the power conversion device. The drive unit includes a switching element drive unit that changes the opening and closing characteristics of the switching elements to drive the switching elements. The control unit includes a first signal generation unit, a second signal generation unit, and a signal transmission unit. The first signal generation unit generates a first setting signal that determines the opening and closing state of at least one switching element among the plurality of switching elements. The second signal generation unit generates a second setting signal that determines the opening and closing characteristics of the at least one switching element in accordance with the state quantities. The signal transmission unit generates a control signal for operating the switching element drive unit based on the first and second setting signals and transmits the control signal to the switching element drive unit.

[0007] The power conversion device according to the present disclosure has the advantage of being able to control noise and loss to a desired state while suppressing an increase in circuit size.

[0008] FIG. 1 is a diagram showing an example of the configuration of a power conversion device according to embodiment 1. FIG. 2 is a diagram showing an example of the turn-on joule loss, turn-on current, and turn-on voltage when the switching speed of the inverter switching elements is slowed in the power conversion device according to embodiment 1. FIG. 3 is a diagram showing an example of the relationship between noise and loss generated in a general switching element. FIG. 4 is a first diagram used to explain the effect obtained by changing the switching speed of the inverter switching elements in the power conversion device according to embodiment 1. FIG. 5 is a second diagram used to explain the effect obtained by changing the switching speed of the inverter switching elements in the power conversion device according to embodiment 1. FIG. 6 is a diagram showing an example of the configuration of a switching element drive unit of a power conversion device according to embodiment 1. FIG. 7 is a diagram showing the signal trains of the basic signal and the switching characteristic setting signal used in embodiment 1 in relation to the carrier signal. FIG. 3 shows the relationship between the gate current output by the switching element drive unit and the gate voltage indicating the rise speed of the switching element in the power conversion device according to embodiment 1. FIG. 4 shows the relationship between the gate current output by the switching element drive unit and the gate voltage indicating the rise speed of the switching element in the power conversion device according to embodiment 1. FIG. 5 shows an example of the relationship between the basic signal output by the basic signal generation unit and the gate current output by the switching element drive unit in the power conversion device according to embodiment 1.

[0009] Hereinafter, a power conversion device, a motor drive device, and a refrigeration cycle applied device according to embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] First Embodiment. Fig. 1 is a diagram showing an example of the configuration of a power conversion device 1 according to a first embodiment. The power conversion device 1 is connected to a commercial power supply 110 and a motor 314. The power conversion device 1 converts first AC power, which is a power supply voltage supplied from the commercial power supply 110, into second AC power having a desired amplitude and phase and supplies the second AC power to the motor 314. In the example of Fig. 1, the commercial power supply 110 is a three-phase AC power supply, but it may also be a single-phase AC power supply. The power conversion device 1 includes a rectifier unit 130, state quantity detection units 501, 502, 505, and 506, a capacitor 210, an inverter 310, a drive unit 320, and a control unit 400. The power conversion device 1 and the motor 314 form a motor drive device 2.

[0011] The rectifier 130 includes, for example, a bridge circuit configured with four rectifier elements (not shown), and a reactor. The rectifier 130 rectifies the AC voltage resulting from the first AC power supplied from the commercial power supply 110 and converts it into DC power. The rectifier 130 may also include a boost chopper circuit or the like.

[0012] The capacitor 210 is connected to the output terminal of the rectifier 130 and smoothes the DC power converted by the rectifier 130. The capacitor 210 is, for example, an electrolytic capacitor or a film capacitor. Note that, since the power conversion device 1 only needs to be able to supply DC power to the inverter 310, the commercial power supply 110, the rectifier 130, and the capacitor 210 may be replaced with a DC power supply, a battery, or the like.

[0013] The state quantity detection unit 501 detects a state quantity that indicates 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, etc.

[0014] The inverter 310 is a power converter connected to both ends of the capacitor 210. The inverter 310 has switching elements 311a to 311f and freewheeling diodes 312a to 312f, which are semiconductor elements. The switching elements 311a to 311f and the freewheeling diodes 312a to 312f are housed in a semiconductor package 342.

[0015] In the inverter 310, switching elements 311a to 311f are controlled to be on or off by a drive unit 320 under the control of a control unit 400. By turning on and off the switching elements 311a to 311f, the inverter 310 converts the DC power output from the rectifier unit 130 and the capacitor 210 into second AC power having a desired amplitude and phase, i.e., generates second AC power, and outputs it to the motor 314. The switching elements 311a to 311f are, for example, insulated gate bipolar transistors (IGBTs), metal oxide semiconductor field effect transistors (MOSFETs), bipolar transistors, etc., but are not limited to these. The circuit configuration of the inverter 310 is not particularly limited and may be a three-phase bridge circuit, a single-phase bridge circuit, a half-bridge circuit, etc. Furthermore, the inverter 310 is not limited to a two-level three-phase bridge circuit, but may be a three-level three-phase bridge circuit.

[0016] The drive unit 320 includes a switching element drive 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 drive unit 340 can output two or more waveform shapes as the switching waveforms of the switching elements 311a to 311f. In the example of FIG. 1, the switching element drive unit 340 is configured to be able to change the switching characteristics of the switching elements 311a to 311f, but it is also possible to change the switching characteristics of at least one of the switching elements 311a to 311f. The drive unit 320, including the switching element drive unit 340, may be a component located inside the inverter 310. In this case, the inverter 310 may be configured to include a switching element drive unit 340 for each of the switching elements 311a to 311f. The detailed operation of the switching element drive unit 340 will be described later.

[0017] 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, a voltage value of the second AC power supplied from the inverter 310 to the motor 314, which is a load, and a current value of the second AC power supplied from the inverter 310 to the motor 314, which is a load. 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, a 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, a current flowing through the switching elements 311b, 311d, and 311f.

[0018] 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 controls the operation of the inverter 310 based on the acquired state quantities, specifically, controls the on / 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 / closing characteristic setting unit 430.

[0019] The basic signal generation unit 410 calculates a duty ratio corresponding to the state quantities detected by the state quantity detection units 501, 502, 505, and 506. The basic signal generation unit 410 also 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 quantities detected by the state quantity detection 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 with a carrier period, which is one period of the carrier signal. The basic signal S1 generated by the basic signal generation unit 410 is a signal that determines the open / closed state of at least one of the switching elements 311a to 311f, i.e., whether the switching element is on or off. In this document, the basic signal generating unit 410 may be referred to as a “first signal generating unit,” and the basic signal S1 may be referred to as a “first setting signal.” The basic signal generating unit 410 outputs the generated basic signal S1 to the signal transmitting unit 420 and the switching characteristic setting unit 430.

[0020] 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 element driving unit 340 of the driving unit 320 changes the switching characteristics of the switching elements 311a to 311f. The switching characteristic setting signal S2 is set in accordance with the state quantities 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 that determines the switching characteristic of at least one of the switching elements 311a to 311f. The carrier signal CA is referenced in generating the switching characteristic setting signal S2.

[0021] Specifically, when switching elements 311a to 311f are turned on and off based on basic signal S1 for controlling the operation of switching elements 311a to 311f of inverter 310, generated by basic signal generator 410, switching characteristic setting unit 430 generates, as switching characteristic setting signal S2, a signal that controls the magnitude of a drive signal used by switching element driver 340 of driver 320 to actually drive switching elements 311a to 311f and the timing at which the drive signal is output. Note that in this document, switching characteristic setting unit 430 may be referred to as a "second signal generator" and switching characteristic setting signal S2 may be referred to as a "second setting signal." Switching characteristic setting unit 430 outputs the generated switching characteristic setting signal S2 to signal transmitter 420.

[0022] The signal transmitting unit 420 generates a control signal CS for operating the switching element driving unit 340 based on the basic signal S1 and the switching characteristic setting signal S2, and transmits the control signal CS to the switching element driving unit 340. When the inverter 310 is configured to include a switching element driving unit 340 for each of the switching elements 311a to 311f, i.e., a configuration including six switching element driving units 340, the control unit 400 may be configured to include a signal transmitting unit 420 for each switching element driving unit 340, i.e., a configuration including six signal transmitting units 420.

[0023] In the example of FIG. 1 , the control unit 400 acquires 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 controls the operation of the inverter 310 based on the acquired state quantities, but this is not limitative. The control unit 400 can control the operation of the inverter 310 based on a state quantity acquired from at least one of the state quantity detection units 501, 502, 505, and 506. In the power conversion device 1, it is not necessary to arrange all of the state quantity detection units 501, 502, 505, and 506 as shown in FIG. 1 . In the power conversion device 1, the state quantity detection units may be provided anywhere other than those shown in the figure, as long as the state quantities can be detected.

[0024] 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 in accordance with 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 considered a constant torque load. The motor 314 may have motor windings (not shown) that are Y-connected or Δ-connected, or may be configured to be switchable between Y-connection and Δ-connection.

[0025] 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, a motor provided in a hand dryer, etc. Furthermore, 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.

[0026] With the above-described configuration, the power conversion device 1 according to the first embodiment can change the switching characteristics of the switching elements 311a to 311f of the inverter 310 by the switching characteristic setting unit 430 and the switching element drive unit 340. Specifically, the power conversion device 1 can change the switching speed, dead time, and the like 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 an arm short circuit, in which the switching elements 311a, 311c, and 311e of the upper arms and the corresponding switching elements 311b, 311d, and 311f of the lower arms are simultaneously turned on.

[0027] Fig. 2 is a diagram showing examples of turn-on joule loss, turn-on current, and turn-on voltage when the opening and closing speed of switching elements 311a to 311f of inverter 310 is slowed down in power conversion device 1 according to embodiment 1. Fig. 3 is a diagram showing examples of turn-on joule loss, turn-on current, and turn-on voltage when the opening and closing speed of switching elements 311a to 311f of inverter 310 is increased in power conversion device 1 according to embodiment 1.

[0028] In Figures 2 and 3, A represents turn-on joule loss, B represents turn-on current, and C represents turn-on voltage. In Figures 2 and 3, the horizontal axis represents time. For example, the turn-on current is the current flowing through switching element 311a, the turn-on voltage is the voltage across switching element 311a, and the turn-on joule loss is the product of the turn-on current and the turn-on voltage. However, the measurement target is not limited to switching element 311a and may also be the other switching elements 311b to 311f. Note that Figures 2 and 3 illustrate the differences in characteristics depending on the switching speed of switching elements 311a to 311f of inverter 310, and the specific values ​​of "slow" and "fast" switching speeds are not particularly important. As shown in Figures 2 and 3, slowing the switching speed reduces noise represented by the peak value of the turn-on current B, but increases loss represented by the area of ​​the turn-on joule loss A. 2 and 3, increasing the switching speed increases the noise represented by the peak value of the turn-on current of B, but decreases the loss represented by the area of ​​the turn-on joule loss of A. In other words, there is a trade-off between the noise and loss generated in the switching elements 311a to 311f.

[0029] In the power conversion device 1, the switching element driver 340 is configured using 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 driver 340 are configured using a digital gate driver module. This allows the power conversion device 1 to change the switching speed of the switching elements 311a to 311f of the inverter 310 by changing software command values ​​without changing the hardware, thereby controlling the noise and loss generated by the switching elements 311a to 311f to a desired state. Note that the function of the switching characteristic setting unit 430 in the control unit 400 can also be configured within the digital gate driver module. In this configuration, the functions of the existing control unit 400 can be used without modification.

[0030] Fig. 4 is a diagram showing an example of the relationship between noise and loss generated in a typical switching element. As mentioned above, there is a trade-off between noise and loss generated in a switching element. Therefore, in a typical switching element, as shown in Fig. 4, increasing the switching speed increases noise but decreases loss, and decreasing the switching speed decreases noise but increases loss.

[0031] FIG. 5 is a first diagram used to explain the effect obtained by changing the switching speed of the switching elements 311a to 311f of the inverter 310 in the power conversion device 1 according to the first embodiment. Even if the power conversion device 1 is operating within the noise range specified for the product in which the power conversion device 1 is installed, when the load state of the motor 314 changes from a light load to a heavy load, the curve showing the characteristics of the noise and loss generated by the switching elements 311a to 311f shifts upward to the upper right as shown in FIG. 5, resulting in an increase in noise. In other words, in the power conversion device 1, the heavier the load, the greater the noise. Therefore, the power conversion device 1 can reduce the noise generated by the switching elements 311a to 311f by slowing down the switching speed of the switching elements 311a to 311f. Similarly, even if the power conversion device 1 is operating within the loss range specified for the product in which the power conversion device 1 is installed, when the load state of the motor 314 changes from a light load to a heavy load, the curve showing the characteristics of the noise and loss generated by the switching elements 311a to 311f shifts to the upper right as shown in Figure 5, resulting in an increase in loss. In other words, in the power conversion device 1, the heavier the load, the greater the 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.

[0032] When the load state of motor 314 changes from a light load to a heavy load, switching characteristic setting unit 430 changes the settings of the switching characteristics of switching elements 311a to 311f so as to reduce losses generated in switching elements 311a to 311f while ensuring that noise generated in switching elements 311a to 311f satisfies specified requirements. Alternatively, when the load state of motor 314 changes from a light load to a heavy load, switching characteristic setting unit 430 changes the settings of the switching characteristics of switching elements 311a to 311f so as to reduce noise generated in switching elements 311a to 311f while ensuring that losses generated in switching elements 311a to 311f satisfy specified requirements.

[0033] 6 is a second diagram used to explain the effect obtained by changing the opening and closing speeds of the switching elements 311a to 311f of the inverter 310 in the power conversion device 1 according to the first embodiment. The power conversion device 1, specifically the switching element driver 340, divides, for example, the turn-on period or the turn-off period of a single switching operation of the switching elements 311a to 311f into two or more periods, and changes the amplitude of the gate current or gate voltage for the switching elements 311a to 311f to different magnitudes in each divided period. By optimizing the switching waveforms of the switching elements 311a to 311f as shown in FIG. 6, the power conversion device 1 can obtain noise and loss characteristics generated by the switching elements 311a to 311f that could not be obtained with typical switching elements such as those shown in FIG. 4.

[0034] Next, the configuration of the switching element driver 340 will be described. Here, for simplicity of explanation, an example will be described in which the switching element driver 340 changes the waveform shape of the switching waveform of one switching element 311a. FIG. 7 is a diagram showing an example configuration of the switching element driver 340 of the power conversion device 1 according to the first embodiment. FIG. 7 is also a diagram showing an example configuration of one digital gate driver configured by the switching element driver 340 and the switching element 311a. The switching element driver 340 includes n P-channel MOSFETs (PMOSs) for turn-on, n PreDrivers for operating the n PMOSs, n N-channel MOSFETs (NMOSs) for turn-off, and n PreDrivers for operating the n NMOSs.

[0035] The switching element driver 340 is connected to a control power supply Vdd and a ground GND. The switching element driver 340 receives a control signal CS transmitted from the signal transmitter 420. The switching element driver 340 changes the number of PMOS or NMOS transistors to be operated in the switching element driver 340 based on the control signal CS. As a result, the switching element driver 340 controls the gate current I, which is a drive signal to be output to the switching element 311a during each of the turn-on period and the turn-off period. Ｇ The switching element driver 340 can change the amplitude value of the gate current I to the switching element 311a in n ways, and adjust the opening and closing speed of the switching element 311a. Ｇ The absolute value of can be increased, and the opening and closing speed of the switching element 311a can be increased. In addition, the switching element driver 340 can adjust the opening and closing speed of the switching element 311a more precisely as the number of PMOS and NMOS included therein increases, and the gate current I ＧThe faster the response of the increase or decrease of the gate current I Ｇ It is possible to adjust the number of PMOS or NMOS transistors operated in the switching element driving unit 340. The control signal CS from the signal transmitting unit 420 may be an analog signal or a digital signal as long as it can change the number of PMOS or NMOS transistors operated in the switching element driving unit 340. In addition, the example in FIG. 7 shows that there are m parallel control signals CS from the signal transmitting unit 420 to the switching element driving unit 340, but this is just an example, and the number of control signals CS is not limited to m. The number of control signals CS may be any number that can indicate whether each PMOS transistor and each NMOS transistor is operable or not, or it may be one signal as long as it is an analog signal that indicates a voltage or the like.

[0036] 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 will be described. Here, similar to the switching element driving unit 340, a case will be described in which the switching element driving unit 340 changes the waveform shape of the switching waveform of one switching element 311a. FIG. 8 is a diagram showing the signal sequences of the basic signal S1 and the switching characteristic setting signal S2 used in the first embodiment in relation to a carrier signal. Specifically, the upper part of FIG. 8 shows a triangular wave signal as an example of the carrier signal. The middle part of FIG. 8 shows a PWM signal as an example of the basic signal S1 that determines the open / close state of the switching element 311a. The lower part of FIG. 8 shows the switching characteristic setting signal S2 that determines the opening / closing characteristic of the switching element 311a. Note that the lower part of FIG. 8 shows the switching characteristic setting signal S2 in a simplified form, but it is assumed that a multi-bit serial signal is transmitted within a period indicated by one pulse.

[0037] 8, the basic signal S1 is generated based on the timing of the valley, which is the bottom of the triangular wave signal. The data length of the basic signal S1 is fixed and is generated on the order of microseconds. One cycle of the basic signal S1 is, for example, 10 μs to 1 ms. In this example, the basic signal S1 with a data length of 10 μs to 1 ms is sent to the signal transmitting unit 420 every 10 μs to 1 ms.

[0038] On the other hand, the switching characteristic setting signal S2 is generated based on the timing of the crest, which is the peak of the triangular wave signal. The data length of the switching characteristic setting signal S2 is variable. The switching characteristic setting signal S2 is generated whenever a change in the switching characteristic is required, i.e., irregularly. As mentioned above, in this paper, the switching characteristic setting signal S2 is assumed to be a multi-bit serial signal. To give a specific example, if a 48-bit pulse signal with a width of 100 μs is sent per cycle, the data length of the switching characteristic setting signal S2 will be 4.8 ms. If at least 10 bits of information are sent, the data length will be more than 1 ms. Therefore, the switching characteristic setting signal S2 is generated on the order of milliseconds and sent to the signal transmitting unit 420.

[0039] In the first embodiment, when the signal transmitting unit 420 has not received 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. Also, in the first embodiment, when the signal transmitting unit 420 has received the switching characteristic setting signal S2, after completing reception of the switching characteristic setting signal S2, it generates the control signal CS using both the basic signal S1 and the switching characteristic setting signal S2 and transmits the control signal CS to the switching element driving unit 340. This allows the switching elements 311a to 311f of the inverter 310 to be driven stably. Furthermore, because the control signal CS reflecting the switching characteristic setting signal S2 quickly changes the switching characteristics of the switching elements 311a to 311f, even if a load fluctuation occurs in a device connected to the motor 314, the load fluctuation can be quickly suppressed.

[0040] Although the above description has been given of the basic signal S1 being generated based on the timing of the valleys of the triangular wave signal and the switching characteristic setting signal S2 being generated based on the timing of the peaks of the triangular wave signal, the present invention is not limited to this. The basic signal S1 may be generated based on the timing of the peaks of the triangular wave signal, and the switching characteristic setting signal S2 may be generated based on the timing of the valleys of the triangular wave signal.

[0041] FIG. 9 shows the gate current I output by the switching element driver 340 in the power conversion device 1 according to the first embodiment. Ｇand the gate voltage V, which indicates the rise speed of the switching element 311a. Ｇ 10 is a first diagram showing the relationship between the gate current I output by the switching element driver 340 in the power conversion device 1 according to the first embodiment. Ｇ and the gate voltage V, which indicates the rise speed of the switching element 311a. Ｇ 9 and 10, the switching element driver 340 outputs a gate current I Ｇ The larger the gate voltage V Ｇ 9 and 10, the switching element driver 340 can increase the rise time of the gate current I Ｇ The smaller the gate voltage V Ｇ 4, the power conversion device 1 can output a gate current I when it is desired to reduce noise generated by the switching element 311a. Ｇ When it is desired to reduce the opening and closing speed by decreasing the value of I and to reduce the loss generated in the switching element 311a, the gate current I Ｇ The switching speed can be increased by increasing the gate current I Ｇ and gate voltage V Ｇ The waveform of the gate current I is an ideal example, and in reality, as shown in FIGS. Ｇ It takes time for the current to reach a constant value.

[0042] FIG. 11 shows the gate current I output by the switching element driver 340 in the power conversion device 1 according to the first embodiment. Ｇ and the gate voltage V, which indicates the rise speed of the switching element 311a. Ｇ 11, the switching element driver 340 divides the turn-on period and controls the gate current I Ｇ That is, the switching element driver 340 can change the magnitude of the gate current IＧ This allows the power conversion device 1 to finely adjust the magnitude of the gate current I Ｇ 6, it is possible to perform control so as to reduce the loss generated in the switching element 311a while reducing the noise generated in the switching element 311a.

[0043] 9 to 11, the turn-on period of the switching element 311a has been described as an example, but the same applies to the turn-off period of the switching element 311a. Fig. 12 shows the basic signal S1 output by the basic signal generating unit 410 and the gate current I output by the switching element driving unit 340 in the power conversion device 1 according to the first embodiment. Ｇ 12 is a diagram illustrating an example of the relationship between |Ig2| and |Ig1|. In FIG. 12, |Ig2|>|Ig1|. The switching element driver 340 controls the gate current I Ｇ The period during which the current Ig2 having the larger amplitude is output is divided, and the gate current I Ｇ Then, the gate current I of the current Ig1 with the next smallest amplitude is output. Ｇ Alternatively, the gate current I of the current Ig1 with the small amplitude may be output first. Ｇ After outputting the gate current I of the current Ig2 with the next largest amplitude, Ｇ Similarly, the switching element driver 340 may output the gate current I Ｇ The period during which the current with the largest amplitude is output is divided, and the gate current I Ｇ Then, the gate current I of the next smallest amplitude current -Ig1 is output. Ｇ Alternatively, the gate current I of the current −Ig1 with a small amplitude may be output first. Ｇ After outputting the next largest current, the gate current Ig2 Ｇ may be output.

[0044] In this way, the switching element driving unit 340 divides at least one of the turn-on period and the turn-off period of the switching element 311a into two or more periods based on the switching characteristics set by the switching characteristic setting unit 430, and controls the gate current I for the switching element 311a in each divided period. Ｇ The switching element driver 340 includes a plurality of transistors, and by changing the number of transistors to be operated based on the switching characteristics set by the switching characteristics setting unit 430, the amplitude of the gate current I Ｇ The amplitude of can be changed.

[0045] In addition, the switching element driver 340 controls the gate current I Ｇ The switching element driver 340 can change the switching characteristics to different ones for each switching period of the switching element 311a during operation of the power conversion device 1. In this case, the switching characteristic setting unit 430 can change the settings of the switching characteristics of the switching element 311a at the same period as the switching period of the switching element 311a. The switching characteristic setting unit 430 may also change the settings of the switching characteristics of the switching element 311a at a period that is a positive integer multiple of the switching period of the switching element 311a.

[0046] 7 is merely an example of the configuration of the switching element driver 340, and is not limited to this. The switching element driver 340 may use transistors other than MOS (Metal Oxide Semiconductor) for the MOS (Metal Oxide Semiconductor) used internally.

[0047] The switching element driver 340 uses digital control with multiple MOS transistors to more precisely adjust the opening and closing speed of the switching element 311a compared to analog control, which physically switches the gate resistor as described in Patent Document 1. Furthermore, since the resistance value of the gate resistor varies with temperature, accuracy in response to temperature fluctuations can be an issue. In contrast, this issue does not arise with a digital gate driver. Therefore, the switching element driver 340, which is configured using a digital gate driver, can precisely adjust the opening and closing speed.

[0048] In the above example, the switching element driver 340 changes the number of PMOS or NMOS transistors to be operated in response to the acquired control signal CS, and controls the gate current I Ｇ to the switching element 311a, but is not limited to this. The switching element driver 340 outputs the gate current I Ｇ The output pattern of the gate current I is stored in advance, and the output pattern corresponds to the acquired control signal CS. Ｇ The switching element driver 340 may output a control signal CS previously acquired and a gate current I Ｇ The output pattern of the gate current I is stored in memory, and when the same control signal CS is acquired, the stored output pattern is used to control the gate current I Ｇ The switching element driver 340 may output a gate current I Ｇ By memorizing the output pattern of the gate current I Ｇ This reduces the processing load when outputting.

[0049] In the above example, the switching element driver 340 outputs a gate current I Ｇ The switching element driver 340 adjusts the switching speed of the switching element 311a by changing the gate voltage VＧ and the gate voltage V Ｇ By changing the value of the switching speed of the switching element 311a, the switching speed of the switching element 311a can be adjusted and the switching characteristics of the switching element 311a can be changed.

[0050] In this way, the switching element driver 340 divides at least one of the turn-on period and the turn-off period of the switching element 311a into two or more periods based on the switching characteristics set by the switching characteristic setting unit 430, and sets the gate voltage V Ｇ The switching element driver 340 includes a plurality of transistors, and by changing the number of transistors to be operated based on the switching characteristics set by the switching characteristic setting unit 430, the amplitude of the gate voltage V Ｇ The amplitude of can be changed.

[0051] Furthermore, when controlling the switching speed, the switching element drive unit 340 may adjust the dead time set in the switching operation of the switching elements 311a to 311f. Specifically, when the switching speed is changed, if the new switching speed is set faster than the old switching speed, the switching element drive unit 340 sets the new dead time shorter than the old dead time. Also, if the new switching speed is set slower than the old switching speed, the switching element drive unit 340 sets the new dead time longer than the old dead time. In this way, the dead time can be appropriately adjusted, thereby reducing the effect of voltage errors caused by the dead time.

[0052] 13 is a flowchart used to explain the operation of changing the switching characteristics 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 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 quantities acquired from the state quantity detection units 501, 502, 505, and 506 (step S1). As described above, in the control unit 400, the basic signal generation unit 410 generates the basic signal S1 based on the state quantities acquired from the state quantity detection units 501, 502, 505, and 506, and determines the timings for turning on and 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.

[0053] 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). The switching characteristic setting signal S2 sets the switching characteristics at the timings at which the switching elements 311a to 311f are turned on and off, which are determined by the basic signal S1.

[0054] Based on the basic signal S1 and the switching characteristic setting signal S2, the signal transmitting unit 420 generates a control signal CS for operating the switching element driving unit 340 (step S3). The control signal CS generated by the signal transmitting unit 420 is transmitted to the switching element driving unit 340. The switching element driving unit 340 changes the switching characteristics of the switching elements 311a to 311f based on the control signal CS received from the signal transmitting unit 420 (step S4).

[0055] As described above, the power conversion device 1 according to embodiment 1 can change the switching characteristics of the switching elements 311a to 311f of the inverter 310 when driving the switching elements 311a to 311f by using the functions of the basic signal generating unit 410, the signal transmitting unit 420, and the switching characteristic setting unit 430 described above.

[0056] Next, a description will be given of the hardware configuration of the control unit 400 included in the power conversion device 1. Fig. 14 is a diagram showing an example of a hardware configuration that realizes 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.

[0057] The processor 91 is a CPU (Central Processing Unit, also called a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, or DSP (Digital Signal Processor)), or a system LSI (Large Scale Integration). Examples of memory 92 include non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory). Memory 92 is not limited to these, and may also be a magnetic disk, optical disk, compact disk, minidisc, or DVD (Digital Versatile Disc).

[0058] As described above, in the power conversion device according to the first embodiment, the control unit controls the operation of the inverter, and the drive unit drives a plurality of switching elements included in the inverter. The drive unit includes a switching element drive unit that changes the opening and closing characteristics of the switching elements to drive the switching elements. The control unit includes first and second signal generation units and a signal transmission unit. The first signal generation unit generates a first setting signal that determines the opening and closing state of at least one switching element among the plurality of switching elements. The second signal generation unit generates a second setting signal that determines the opening and closing characteristics of the at least one switching element in accordance with a state quantity. The signal transmission unit generates a control signal that operates the switching element drive unit based on the first and second setting signals and transmits the control signal to the switching element drive unit. This allows the power conversion device to change the opening and closing characteristics of the switching elements while suppressing an increase in circuit size.

[0059] Furthermore, in the power conversion device according to the first embodiment, the switching element driver is configured to divide at least one of the turn-on period and the turn-off period of the switching element into two or more periods based on the switching characteristics set by the switching characteristic setting signal, and to change the amplitude of the gate current or gate voltage for the switching element to a different magnitude in each divided period. This power conversion device configured in this manner can finely adjust the gate current or gate voltage output to the switching element in one switching period, thereby achieving switching characteristics that could not be achieved by the method described in Patent Document 1 and the like. This makes it possible to control noise and loss to desired states while suppressing an increase in circuit size.

[0060] Furthermore, in the power conversion device according to the first embodiment, when the second setting signal has not been received, the signal transmitter generates a control signal using only the first setting signal. When the second setting signal has been received, the signal transmitter generates a control signal using both the first and second setting signals after the second setting signal has been received. As a result, the second setting signal that has been received is quickly reflected in the control of the switching characteristics. This allows load fluctuations occurring in the power conversion device to be quickly suppressed.

[0061] Second Embodiment. Fig. 15 is a diagram showing a configuration example of a power conversion device 1A according to a second embodiment. In the second embodiment, a motor drive device 2A is configured by the power conversion device 1A and a motor 314. In the power conversion device 1A according to the second embodiment, in the configuration of Fig. 1, the drive unit 320 is replaced with a drive unit 320A, the control unit 400 is replaced with a control unit 400A, and the signal transmission unit 420 is replaced with a signal transmission unit 420A. In addition, a signal receiving unit 350 is added to the drive unit 320A in Fig. 15. The other configuration is the same as or equivalent to that of the power conversion device 1 shown in Fig. 1, and the same or equivalent components are designated by the same reference numerals, and redundant description will be omitted.

[0062] The signal transmitting section 420A transmits the basic signal S1 sent from the basic signal generating section 410 to the signal receiving section 350 of the driving section 320A. The transmission of the basic signal S1 may be parallel transmission or serial transmission. The signal transmitting section 420A also transmits the switching characteristic setting signal S2 sent from the switching characteristic setting section 430 to the signal receiving section 350 of the driving section 320A. In the second embodiment, the transmission of the switching characteristic setting signal S2 is performed by serial transmission. Any synchronization method may be used for synchronization in serial transmission. Typical synchronization methods include start-stop synchronization, independent synchronization, and frame synchronization.

[0063] FIG. 16 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 a carrier signal. The upper part of FIG. 16 shows a triangular wave signal, which is an example of the carrier signal. The upper-middle part of FIG. 16 shows a PWM signal, which is an example of the basic signal S1 that determines the open / close state of the switching element 311a. The lower-middle part of FIG. 16 shows the switching characteristic setting signal S2 that determines the switching characteristic of the switching element 311a. The triangular wave signal, the basic signal S1, and the switching characteristic setting signal S2 are basically the same as those described in the first embodiment. The lower part of FIG. 16 also shows the switching characteristic switching signal. This switching characteristic switching signal is superimposed on the switching characteristic setting signal S2 and transmitted to the signal receiving unit 350 of the driver 320A.

[0064] The switching characteristic switching signal is a timing signal that specifies the timing for switching the switching characteristics of the switching 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 switching elements 311a to 311f.

[0065] Therefore, in the control of the second embodiment, it is possible to simultaneously change the switching characteristics of multiple switching elements at a timing when none of the multiple switching elements are performing switching operations. This type of control is useful in applications with a large number of switching elements, such as inverter drive of a three-phase motor. By simultaneously changing the switching characteristics of multiple switching elements, it is possible to drive a load stably.

[0066] As described above, in the power conversion device according to the second embodiment, the control unit controls the operation of the inverter, and the drive unit drives multiple switching elements included in the inverter. The control unit includes first and second signal generation units and a signal transmission unit. The drive unit includes a switching element drive unit and a signal reception unit. The first signal generation unit generates a first setting signal that determines the open / close state of at least one switching element among the multiple switching elements. The second signal generation unit generates a second setting signal that determines the open / close characteristics of the at least one switching element according to the state quantity. The signal transmission unit transmits the first and second setting signals to the drive unit. The signal reception unit generates a control signal CS that operates the switching element drive unit based on the first and second setting signals received from the control unit. The switching element drive unit changes the open / close characteristics of the switching elements based on the control signal CS. This allows the power conversion device to change the open / close characteristics of the switching elements, including the opening and closing speed, while suppressing an increase in circuit size. Furthermore, the power conversion device can simultaneously change the switching characteristics of a plurality of switching elements, and therefore can stably drive the load even when the switching characteristics are changed.

[0067] Third Embodiment Fig. 17 is a diagram showing a configuration example of a power conversion device 1B according to a third embodiment. In the third embodiment, a motor drive device 2B is configured by the power conversion device 1B and a motor 314. In the power conversion device 1B according to the third embodiment, the drive unit 320A in the configuration of Fig. 15 is replaced with a drive unit 320B. In the drive unit 320B of Fig. 17, a noise suppression unit 360 is added to the input side of the signal receiving unit 350. The other configurations are the same as or equivalent to those of the power conversion device 1A shown in Fig. 15, and the same or equivalent components are designated by the same reference numerals, and redundant description will be omitted.

[0068] The noise suppression unit 360 suppresses 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 configured as an RC filter using a resistor and a capacitor. Alternatively, the low-pass filter may be configured using only a capacitor. As described above, noise increases when the switching speed of the switching elements 311a to 311f is fast. Therefore, when the signal receiving unit 350 is located near the semiconductor package 342 or inside the semiconductor package 342, high-frequency noise is likely to be superimposed on the switching characteristic setting signal S2 received by the signal receiving unit 350. Therefore, in the third embodiment, the noise suppression unit 360 suppresses high-frequency noise that may be contained in the switching characteristic setting signal S2. This prevents the switching characteristics of the switching elements 311a to 311f 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.

[0069] In the third embodiment, only the switching characteristic setting signal S2 is passed through the noise suppression unit 360, but this is not limiting. The basic signal S1 may also be passed through the noise suppression unit before being received by the signal receiving unit 350.

[0070] As described above, according to the power conversion device of the third embodiment, in the configuration of the second embodiment, the drive unit includes a noise suppression unit that suppresses high-frequency noise, and the signal receiving unit receives at least one of the first and second setting signals transmitted from the signal transmitting unit via the noise suppression unit. This makes it 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 elements from being erroneously changed.

[0071] Fourth Embodiment. Fig. 18 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. In the power conversion device 1C according to the fourth embodiment, in the configuration of Fig. 17, the drive unit 320B is replaced with a drive unit 320C, and the control unit 400A is replaced with a control unit 400C. In the drive unit 320C of Fig. 18, the signal receiving unit 350 is replaced with a signal transmitting / receiving unit 350C. Furthermore, in the control unit 400C of Fig. 18, the signal transmitting unit 420A is replaced with a signal transmitting / receiving unit 420C. The other configurations are the same as or equivalent to those of the power conversion device 1B shown in Fig. 17, and the same or equivalent components are designated by the same reference numerals, and redundant description will be omitted. In this document, the signal transmitting / receiving unit 420C may be referred to as a "first transmitting / receiving unit," and the signal transmitting / receiving unit 350C may be referred to as a "second transmitting / receiving unit."

[0072] The signal transmitter / receiver 350C has the functions of the signal receiver 350 described above, and further generates an implementation signal CV indicating that change control of the switching characteristics has been carried out, and transmits the implementation signal CV to the signal transmitter / receiver 420C of the control unit 400C. When the signal transmitter / receiver 420C receives the implementation signal CV, the control unit 400C can determine that the switching characteristics of the switching elements 311a to 311f have been changed. In other words, the control unit 400C can determine the operating status of the switching element driver 340 and the signal transmitter / receiver 350C based on the implementation signal CV.

[0073] In the fourth embodiment, the configuration in which a transmission function is added to the drive unit side and a reception function is added to the control unit side is applied to the configuration of the third embodiment shown in FIG. 17, but it can also be applied to the configuration of the second embodiment shown in FIG. 15.

[0074] As described above, according to the power conversion device of embodiment 4, in the configurations of embodiments 2 and 3, the control unit includes a first signal transceiver that transmits first and second setting signals to the drive unit and receives from the drive unit an implementation signal indicating that control to change the switching characteristics of the switching element has been performed. The drive unit also includes a second signal transceiver that generates a control signal for operating the switching element drive unit based on the first and second setting signals received from the control unit and transmits the implementation signal to the control unit when control to change the switching characteristics of the switching element has been performed. This allows the control unit to grasp the operating status of the drive unit.

[0075] Fifth Embodiment. Fig. 19 is a diagram showing a configuration example of a refrigeration cycle-applied apparatus 900 according to a fifth embodiment. The refrigeration cycle-applied apparatus 900 according to the fifth embodiment includes the power conversion device 1 described in the first embodiment. The refrigeration cycle-applied apparatus 900 according to the fifth embodiment may also include the power conversion devices 1A to 1C described in the second to fourth embodiments. The refrigeration cycle-applied apparatus 900 according to the fifth embodiment may be applied to products equipped with a refrigeration cycle, such as air conditioners, refrigerators, freezers, and heat pump water heaters. In Fig. 19, components having the same functions as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

[0076] The refrigeration cycle application equipment 900 includes a compressor 315 incorporating the 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, which are attached via refrigerant piping 912.

[0077] Inside the compressor 315, a compression mechanism 904 that compresses the refrigerant and a motor 314 that operates the compression mechanism 904 are provided.

[0078] The refrigeration cycle device 900 can perform heating or cooling operation by switching the four-way valve 902. The compression mechanism 904 is driven by a motor 314 that is variably controlled in speed.

[0079] During heating operation, as shown by the solid arrow, the refrigerant is pressurized by the compression mechanism 904 and sent out, passes 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 and returns to the compression mechanism 904.

[0080] During cooling operation, as shown by the dashed arrow, the refrigerant is pressurized by the compression mechanism 904 and 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.

[0081] During heating operation, the indoor heat exchanger 906 acts as a condenser to release heat, and the outdoor heat exchanger 910 acts as an evaporator to absorb heat. During cooling operation, the outdoor heat exchanger 910 acts as a condenser to release heat, and the indoor heat exchanger 906 acts as an evaporator to absorb heat. The expansion valve 908 reduces the pressure of the refrigerant to expand it.

[0082] Even if the refrigeration cycle apparatus 900 is operating within a specified noise range, when the load state of the motor 314 changes from a light load to a heavy load, the curve showing the characteristics of the noise and loss generated by the switching elements 311a to 311f, etc., shifts upward to the upper right as shown in FIG. 5 , resulting in an increase in noise. Therefore, the refrigeration cycle apparatus 900 can reduce the noise generated by the switching elements 311a to 311f, etc., by slowing the opening and closing speed of the switching elements 311a to 311f, etc. Similarly, even if the refrigeration cycle apparatus 900 is operating within a specified loss range, when the load state of the motor 314 changes from a light load to a heavy load, the curve showing the characteristics of the noise and loss generated by the switching elements 311a to 311f, etc., shifts upward to the upper right as shown in FIG. 5 , resulting in an increase in loss. Therefore, the refrigeration cycle apparatus 900 can reduce the loss generated by the switching elements 311a to 311f, etc., by increasing the opening and closing speed of the switching elements 311a to 311f, etc.

[0083] In the power conversion device 1 included in the refrigeration cycle device 900, a digital gate driver configured by the switching element drive unit 340 and the switching elements 311a to 311f included in the drive unit 320 generates a large surge voltage and a lot of electromagnetic noise when the switching speed is fast. When the refrigeration cycle device 900 uses a flammable refrigerant, there is a possibility that the refrigerant may leak and burn due to discharge caused by electromagnetic noise. Therefore, the refrigeration cycle device 900 sets the switching speed of the digital gate driver included in the power conversion device 1 according to the flammability of the refrigerant used in the refrigeration cycle device 900. For example, the refrigeration cycle device 900 slows the switching speed of the digital gate driver included in the power conversion device 1 the higher the flammability of the refrigerant used in the refrigeration cycle device 900. By slowing the switching speed of the digital gate driver, the refrigeration cycle device 900 can reduce surge voltage and suppress discharge caused by electromagnetic noise, thereby preventing refrigerant from burning even if it leaks from the refrigeration cycle device 900.

[0084] Refrigerants used in the refrigeration cycle equipment 900 include, for example, R1234yf, R1234ze(E), R1243zf, HFO1123, HFO1132(E), R1132a, CF3I, R290, R463A, R466A, R454A, R454B, and R454C.

[0085] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. It is also possible to omit or modify parts of the configurations as long as they do not deviate from the gist of the invention.

[0086] 1, 1A, 1B, 1C Power conversion device, 2, 2A, 2B, 2C Motor drive device, 91 Processor, 92 Memory, 110 Commercial power supply, 130 Rectification unit, 210 Capacitor, 310 Inverter, 311a to 311f Switching elements, 312a to 312f Freewheeling diodes, 314 Motor, 315 Compressor, 320, 320A, 320B, 320C Drive unit, 340 Switching element drive unit, 342 Semiconductor package, 350 Signal receiving unit, 350C, 420C Signal transmitting / receiving unit, 360 Noise suppression unit, 400, 400A, 400C Control unit, 410 Basic signal generation unit, 420, 420A Signal transmitting unit, 430 Open / close characteristic setting unit, 501, 502, 505, 506 State quantity detection unit, 900 refrigeration cycle applicable 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 including an inverter having a plurality of switching elements and converting DC power into AC power having a desired amplitude and phase, a control unit for controlling an operation of the inverter, and a drive unit for driving the plurality of switching elements, the power conversion device supplying power to a motor that drives a load via the inverter, the power conversion device includes a state quantity detection unit that detects a state quantity indicating an operation state of the power conversion device, the drive unit includes a switching element drive unit that drives the switching element by changing an opening / closing characteristic of the switching element, The control unit is a first signal generating unit that generates a first setting signal that determines an open / closed state of at least one of the plurality of switching elements; a second signal generating unit configured to generate a second setting signal that determines an opening / closing characteristic of the at least one switching element in response to the state quantity; a signal transmission unit that generates a control signal for operating the switching element drive unit based on the first and second setting signals and transmits the control signal to the switching element drive unit. Power conversion equipment.

2. the first setting signal is a pulse width modulated signal; The second setting signal is a serial signal. The power conversion device according to claim 1 .

3. The signal transmission unit is When the second setting signal is not received, the control signal is generated using only the first setting signal; When the second setting signal is received, after the reception of the second setting signal is completed, the control signal is generated using both the first and second setting signals. The power conversion device according to claim 1 .

4. A power conversion device including an inverter having a plurality of switching elements, a control unit that controls an operation of the inverter, and a drive unit that drives the plurality of switching elements, the power conversion device supplying power to a motor that drives a load via the inverter, the power conversion device includes a state quantity detection unit that detects a state quantity indicating an operation state of the power conversion device, The control unit is a first signal generating unit that generates a first setting signal that determines an open / closed state of at least one of the plurality of switching elements; a second signal generating unit configured to generate a second setting signal that determines an opening / closing characteristic of the at least one switching element in response to the state quantity; a signal transmission unit that transmits the first and second setting signals to the drive unit. The drive unit is A switching element driver that changes the opening and closing characteristics of the switching element; a signal receiving unit that generates a control signal for operating the switching element driving unit based on the first and second setting signals received from the control unit. Power conversion equipment.

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

6. The driving unit includes a noise suppression unit that suppresses high-frequency noise, The signal receiving unit receives at least one of the first and second setting signals transmitted from the signal transmitting unit via the noise suppressing unit. The power conversion device according to claim 4.

7. A power conversion device including an inverter having a plurality of switching elements, a control unit that controls an operation of the inverter, and a drive unit that drives the plurality of switching elements, the power conversion device supplying power to a motor that drives a load via the inverter, the power conversion device includes a state quantity detection unit that detects a state quantity indicating an operation state of the power conversion device, The control unit is a first signal generating unit that generates a first setting signal that determines an open / closed state of at least one of the plurality of switching elements; a second signal generating unit configured to generate a second setting signal that determines an opening / closing characteristic of the at least one switching element in response to the state quantity; a first signal transmitting / receiving unit that transmits the first and second setting signals to the driving unit and receives an implementation signal indicating that the switching element has been subjected to change control of the opening / closing characteristics from the front driving unit; The drive unit is A switching element driver that changes the opening and closing characteristics of the switching element; a second signal transmitting / receiving unit that generates a control signal for operating the switching element driving unit based on the first and second setting signals received from the control unit, and transmits the implementation signal to the control unit when control for changing the opening / closing characteristics of the switching element is executed. Power conversion equipment.

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

9. The driving unit includes a noise suppression unit that suppresses high-frequency noise, The second signal transmitting / receiving unit receives at least one of the first and second setting signals transmitted from the first signal transmitting / receiving unit via the noise suppressing unit. The power converter according to claim 7.

10. A refrigeration cycle application device comprising the power conversion device according to any one of claims 1 to 9, The opening and closing speed of a digital gate driver provided in the power conversion device is set according to the flammability of a refrigerant used in the refrigeration cycle application equipment. Refrigeration cycle application equipment.