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

Abstract

A power conversion device (1) that performs power conversion is provided with: one or more switching elements included in at least one of the one or more power converters that perform power conversion; a waveform shape changing unit capable of changing the waveform shape of the switching waveform of the switching element; state quantity detection units (501-505) that detect a state quantity indicating the operating state of the power conversion device (1); and a waveform shape control signal output unit (420) that outputs a control signal when the switching waveform of the switching element is changed by the waveform shape changing unit on the basis of the state quantity.

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 changing the gate drive waveform of the switching element, 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] However, according to the above-mentioned prior art, a switch is used to switch the gate resistor connected to the switching element. Therefore, when the types of gate drive waveforms increase, a large number of gate resistors and switches need to be used, which has a problem of increasing the circuit scale.

[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 changing the switching speed of a switching element while suppressing an increase in circuit scale.

[0009] Means used to solve problems

[0010] In order to solve the above problems and achieve the purpose, the present disclosure is a power conversion device for performing power conversion. The power conversion device comprises: one or more switching elements, which are included in at least one of the one or more power converters for performing power conversion; a waveform shape changing unit, which can change the waveform shape of the switching waveform of the switching element; a state quantity detection unit, which detects the state quantity representing the operation state of the power conversion device; and a waveform shape control signal output unit, which outputs a control signal when the switching waveform of the switching element is changed by the waveform shape changing unit according to the state quantity.

[0011] Effects of the Invention

[0012] The power conversion device of the present disclosure has an effect of being able to change the switching speed of the switching element while suppressing an increase in the circuit scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1This 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 switching 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-current, and on-voltage when the switching 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 generated by a general switching element and loss.

[0017] Figure 5 FIG. 1 is a first diagram showing the effect obtained by changing the switching 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 showing the effect obtained by changing the switching 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 waveform shape changing unit of the power conversion device according to the first embodiment.

[0020] Figure 8 1 is a first diagram showing the relationship between the gate current outputted from the waveform shape changing unit and the gate voltage indicating the rising speed of the switching element in the power conversion device according to the first embodiment.

[0021] Fig. 9 The second diagram shows the relationship between the gate current output by the waveform shape changing unit and the gate voltage indicating the rising speed of the switching element in the power conversion device according to the first embodiment.

[0022] Fig.10 FIG. 3 is a third diagram showing the relationship between the gate current outputted from the waveform shape changing unit and the gate voltage indicating the rising speed of the switching element in the power conversion device according to the first embodiment.

[0023] Fig.11 This is a diagram showing an example of the relationship between the basic pulse output by the basic pulse generating unit and the gate current output by the waveform shape changing unit in the power conversion device according to the first embodiment.

[0024] Fig.12 This is a flowchart showing an operation of changing the waveform shape of the switching waveform of the switching element in the power conversion device according to the first embodiment.

[0025] Fig.13 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.

[0026] Fig.14 This is a diagram showing a configuration example of a power conversion device according to the second embodiment.

[0027] Fig.15 FIG. 1 is a first diagram showing a rectifying portion of an inverter included in a power conversion device according to a second embodiment.

[0028] Fig.16 FIG. 2 is a second diagram showing a rectifying portion of an inverter included in the power conversion device according to the second embodiment.

[0029] Fig.17 FIG. 3 is a third diagram showing a rectifying portion of an inverter included in the power conversion device according to the second embodiment.

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

[0031] Fig.19 This is a diagram showing a configuration example of a power conversion device according to a fourth embodiment.

[0032] Fig. 20 It is a diagram showing a configuration example of a speed estimation device included in a power conversion device according to a fourth embodiment.

[0033] Fig.21 It is a diagram showing a configuration example of a power conversion device according to a fifth embodiment.

[0034] Fig. 22 As a comparative example, the diagram shows an example of each current and a capacitor voltage of the capacitor when the current output from the rectifier is smoothed by the capacitor and the current flowing to the inverter is made constant.

[0035] Fig.23 This is a diagram showing an example of each current and the capacitor voltage of the capacitor when the control unit of the power conversion device according to the fifth embodiment controls the operation of the inverter to reduce the current flowing through the capacitor.

[0036] Fig.24 This is a diagram showing a configuration example of a power conversion device according to a sixth embodiment.

[0037] Fig.25 This is a diagram showing a configuration example of a refrigeration cycle application device according to the seventh embodiment. DETAILED DESCRIPTION

[0038] 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.

[0039] Implementation method 1.

[0040] 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 having a power source voltage Vs 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 , a single-phase AC power supply is used, but a three-phase AC power supply may also be used. The power conversion device 1 includes a state quantity detection unit 501, a converter 130, a capacitor 210, a state quantity detection unit 502, an inverter 310, a state quantity detection unit 503, a state quantity detection unit 504, a state quantity detection unit 505, and a control unit 400. In addition, the power conversion device 1 and the motor 314 constitute a motor drive device 2.

[0041] 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 AC power of the power supply voltage Vs supplied from the commercial power supply 110 to the inverter 130, a current value of the AC power of the power supply voltage Vs supplied from the commercial power supply 110 to the inverter 130, and the like.

[0042] The inverter 130 is a power converter that converts AC power of a power supply voltage Vs supplied from a commercial power supply 110 into DC power. The inverter 130 includes rectifying elements 131 to 134, a reactor 135, a switching element 136, a flyback diode 137, a diode 138, and a drive circuit 150. The inverter 130 has a bridge circuit composed of rectifying elements 131 to 134, which rectifies the first AC power of a power supply voltage Vs supplied from the commercial power supply 110, and outputs the rectified DC power by boosting the voltage. The drive circuit 150 generates a drive signal for actually driving the switch element 136 based on a basic pulse generated by a basic pulse generating unit 410 of a control unit 400 described later. The switch element 136 is, for example, an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a bipolar transistor, etc., but is not limited thereto. In addition, the structure of the inverter 130 is not limited to Figure 1Inverter 130 may also be configured by using a switching element to form one or more of the rectifying elements 131 to 134. Figure 1 In the power conversion device 1 of the first embodiment shown, the inverter 130 may have only a rectifying function and not a boosting function. In addition, when the commercial power supply 110 is a three-phase AC power supply, the inverter 130 is configured to include six rectifying elements.

[0043] The capacitor 210 is connected to the output end of the inverter 130, and smoothes the DC power converted by the inverter 130. The capacitor 210 is, for example, an electrolytic capacitor, a film capacitor, or the like.

[0044] 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 DC power supplied from the capacitor 210 to the inverter 310, and the like.

[0045] 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. The inverter 310 switches the switching elements 311a to 311f on and off under the control of the control unit 400, converts the power output from the converter 130 and the capacitor 210 into a second AC power having a desired amplitude and phase, that is, generates the second AC power, and outputs it to the motor 314. The switching elements 311a to 311f are, for example, IGBTs, MOSFETs, bipolar transistors, etc., but are not limited thereto. The circuit structure of the inverter 310 is a full-bridge circuit, a single-phase bridge circuit, a half-bridge circuit, etc., and is not particularly limited. In addition, in the present embodiment, the inverter 310 has a waveform shape changing unit 340 that can change the waveform shape of the switching waveform of the switching elements 311a to 311f. The waveform shape changing unit 340 can output two or more waveform shapes as the waveform shapes of the switching waveforms of the switching elements 311a to 311f. Figure 1 In the example of FIG. 3 , the waveform shape changing unit 340 is a structure capable of changing the waveform shape of the switching waveform of the switching elements 311a to 311f, but is set to be capable of changing the waveform shape of the switching waveform of at least one of the switching elements 311a to 311f. In addition, the inverter 310 may also be a structure including the waveform shape changing unit 340 for each switching element 311a to 311f. The detailed operation of the waveform shape changing unit 340 will be described later.

[0046] The state quantity detection unit 503 detects a state quantity indicating the operating state of the power conversion device 1. The state quantity detection unit 503 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 504 detects a state quantity indicating the operating state of the power conversion device 1. The state quantity detection unit 504 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 505 detects a state quantity indicating the operating state of the power conversion device 1. The state quantity detection unit 505 detects, for example, currents flowing to the switching elements 311b, 311d, and 311f, etc.

[0047] The control unit 400 obtains the state quantities detected by the state quantity detection units 501 to 505 from the state quantity detection units 501 to 505, and controls the operation of the converter 130 and the inverter 310 based on the obtained state quantities, specifically, controls the on and off of the switching element 136 of the converter 130, and controls the on and off of the switching elements 311a to 311f of the inverter 310. The control unit 400 includes a basic pulse generation unit 410 and a waveform shape control signal output unit 420.

[0048] The basic pulse generator 410 generates a basic pulse having a duty ratio corresponding to the state quantity detected by the state quantity detectors 501 to 505 and used to control the operation of the switching element 136 of the converter 130. In addition, the basic pulse generator 410 generates a basic pulse having a duty ratio corresponding to the state quantity detected by the state quantity detectors 501 to 505 and used to control the operation of the switching elements 311a to 311f of the inverter 310. The basic pulse is, for example, a PWM (Pulse Width Modulation) signal having a duty ratio corresponding to the state quantity detected by the state quantity detectors 501 to 505. The basic pulse generator 410 outputs the basic pulse for controlling the operation of the switching element 136 of the converter 130 to the converter 130, and outputs the basic pulse for controlling the operation of the switching elements 311a to 311f of the inverter 310 to the waveform shape control signal output unit 420.

[0049] The waveform shape control signal output unit 420 sets the waveform shape of the switching waveform of the switching elements 311a to 311f when the waveform shape change unit 340 of the inverter 310 changes the switching waveform of the switching elements 311a to 311f based on the state quantity detected by the state quantity detection units 501 to 505, and outputs a control signal indicating the set waveform shape. Specifically, the waveform shape control signal output unit 420 controls the magnitude of the drive signal output to the switching elements 311a to 311f and the timing of outputting the drive signal when the switching elements 311a to 311f are turned on and off based on the basic pulses generated by the basic pulse generation unit 410 for controlling the operation of the switching elements 311a to 311f of the inverter 310. The waveform shape control signal output unit 420 outputs the control signal for controlling the operation of the waveform shape change unit 340 to the waveform shape change unit 340. Alternatively, when the inverter 310 includes a waveform changer 340 for each switching element 311a to 311f, i.e., includes six waveform changers 340 , the control unit 400 may include a waveform control signal output unit 420 for each waveform changer 340 , i.e., includes six waveform control signal output units 420 .

[0050] In addition, Figure 1 In the example, the control unit 400 obtains the state quantities detected by the state quantity detection units 501 to 505 from the state quantity detection units 501 to 505, and controls the operation of the converter 130 and the inverter 310 based on the obtained state quantities, but is not limited to this. The control unit 400 can control the operation of the converter 130 and the inverter 310 based on the state quantity obtained from at least one of the state quantity detection units 501 to 505. In the power conversion device 1, in the above-mentioned example, the state quantity detection units 501 to 505 detect the voltage or current input to each structure of the power conversion device 1, the voltage or current output from each structure of the power conversion device 1, etc. as the state quantity, but the detection object is not limited to this. In addition, the setting position of the state quantity detection units 501 to 505 is not limited to Figure 1 The power conversion device 1 does not need to be in accordance with Figure 1 All state quantity detection units 501 to 505 are configured in this way. As long as the state quantity can be detected, the power conversion device 1 may include a state quantity detection unit at any position other than the position shown in the figure. The power conversion device 1 may also use the noise generated by the power conversion device 1, the motor 314, etc., the loss generated by the power conversion device 1, the motor 314, etc., the temperature of each structure of the power conversion device 1, the motor 314, etc. as the state quantity, and include a state quantity detection unit at a position where these state quantities can be detected.

[0051] In addition, the basic pulse generating unit 410 and the waveform shape control signal output unit 420 of the control unit 400 both operate based on the state quantity obtained from the state quantity detecting units 501 to 505, so the functions of the basic pulse generating unit 410 and the waveform shape control signal output unit 420 can also be integrated into one structure.

[0052] The motor 314 is a load connected to the power conversion device 1. The motor 314 is, for example, a compressor 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 action. 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 Y connection and Δ connection. In addition, the load connected to the power conversion device 1, i.e., the inverter 310, is not limited to the motor 314 for driving the compressor, and can also be a fan motor or the like. In addition, the load connected to the power conversion device 1 is not limited to the motor 314, and can also be a load other than the motor 314.

[0053] In the present embodiment, the power conversion device 1 can change the waveform shape of the switching waveform of the switching elements 311a to 311f of the inverter 310 through the waveform shape control signal output unit 420 and the waveform shape change unit 340. Specifically, the power conversion device 1 can change the switching speed, delay time, etc. of the switching elements 311a to 311f of the inverter 310.

[0054] Figure 2 This is a diagram showing an example of the conduction Joule loss, the on-current, and the on-voltage when the switching 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 1 is a diagram showing an example of conduction Joule loss, conduction current, and conduction voltage when the switching speed of the switching elements 311a to 311f of the inverter 310 is increased in the power conversion device 1 according to the first embodiment. 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 3 In the figure, the horizontal axis represents time. For example, the on-current is the current flowing to 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 3The difference in characteristics caused by the switching speed of the switching elements 311a to 311f of the inverter 310 is shown, and the specific values ​​of "slow" and "fast" of the switching 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 decreases, but the loss indicated by the area of ​​the on-joule loss of A increases. 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.

[0055] In the power conversion device 1, the waveform shape changing 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 waveform shape changing unit 340 are constituted by a digital gate driver module. Thus, the power conversion device 1 can change the switching speed of the switching elements 311a to 311f of the inverter 310 by changing the command value of the software without changing the hardware, and can control the noise and loss generated by the switching elements 311a to 311f to a desired state.

[0056] Figure 4 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, Figure 4 As shown, in a conventional switching element, 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.

[0057] Figure 5 1 is a first diagram showing 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 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 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 switching 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 5As 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 switching speed of the switching elements 311a to 311f.

[0058] When the load state of the motor 314 changes from a light load to a heavy load, the waveform shape control signal output unit 420 changes the waveform shape of the switching waveform of the switching elements 311a to 311f so that the noise generated by the switching elements 311a to 311f satisfies the prescribed requirements 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 waveform shape control signal output unit 420 changes the waveform shape of the switching waveform of the switching elements 311a to 311f so that the loss generated by the switching elements 311a to 311f satisfies the prescribed requirements and the noise generated by the switching elements 311a to 311f is reduced.

[0059] Figure 6 FIG. 2 is a diagram showing 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 of the first embodiment. Specifically, the waveform shape changing unit 340 of 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 magnitudes 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.

[0060] Here, a description is given of the configuration of the waveform shape changing unit 340. Here, as an example, in order to simplify the description, a description is given of a case where the waveform shape changing unit 340 can change the waveform shape of the switching waveform of one switching element 311a. Figure 7 This is a diagram showing a configuration example of the waveform shape changing unit 340 of the power conversion device 1 according to the first embodiment. Figure 7 This is also a diagram showing a configuration example of a digital gate driver module composed of a waveform shape changing unit 340 and a switching element 311a. Figure 1As shown, the waveform shape changing unit 340 is included in the inverter 310, and the inverter 310 is a power converter including a switching element 311a. The waveform shape changing unit 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.

[0061] The waveform changing unit 340 is connected to the control power supply Vdd and the ground GND. The waveform changing unit 340 changes the number of PMOS or NMOS to be operated based on the control signal from the waveform control signal output unit 420, and can change the gate current I as the driving 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 switching speed of the switch element 311a. The more the waveform shape changer 340 increases the number of PMOS or NMOS in operation, 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 switching element 311a can be. In addition, for the waveform shape changing unit 340, the more PMOS and NMOS are provided inside, the more finely the switching speed of the switching 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. G The control signal from the waveform shape control signal output unit 420 can be either an analog signal or a digital signal as long as the number of PMOS or NMOS to be operated can be changed by the waveform shape change unit 340. Figure 7 In the example of FIG. 4 , m control signals are connected in parallel from the waveform shape control signal output unit 420 to the waveform shape changing unit 340. However, this is an example, and the number of control signals is not limited to m. The number of control signals 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 of control signals may be 1.

[0062] Figure 8 1 is a graph showing the gate current I outputted by the waveform shape changing unit 340 in the power conversion device 1 according to the first embodiment. GThe gate voltage V G Figure 1 of the relationship. Fig. 9 1 is a graph showing the gate current I outputted by the waveform shape changing 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. Figure 8 and Fig. 9 As shown in FIG. 1 , the waveform shape changing unit 340 increases the output gate current I G , the faster the gate voltage V G The higher the value, the faster the switching speed of the switching element 311a can be made. Figure 8 and Fig. 9 As shown in FIG. 1 , the waveform shape changing unit 340 decreases the output gate current I G , the more it can slow down the gate voltage V G The higher the value, the slower the switching speed of the switching element 311a can be. Figure 5 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 and reducing the loss caused by the switching element 311a, the output gate current I can be increased. G This makes the switching speed faster. In addition, Figure 8 and Fig. 9 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.

[0063] Fig.10 1 is a graph showing the gate current I outputted by the waveform shape changing 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.10 As shown, the waveform shape changing unit 340 can divide the conduction period and change the gate current I G That is, the waveform shape changing unit 340 can finely adjust the gate current I within one conduction period. G Thus, the power conversion device 1 outputs the same gate current I as during the on period. G Compared with the situation Figure 6As shown, control is performed to reduce the noise generated by the switching element 311a and reduce the loss generated by the switching element 311a.

[0064] use Figures 8 to 10 , 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.11 FIG. 1 is a diagram showing the relationship between the basic pulse output by the basic pulse generating unit 410 and the gate current I output by the waveform shape changing unit 340 in the power conversion device 1 according to the first embodiment. G The following is an example of a relationship between . Fig.11 In the on-period of the switching element 311a, the waveform shape changing unit 340 controls the output 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 waveform shape changing unit 340 changes the output gate current I during the off period of the switching element 311a. G During the period of division, the gate current I with a large amplitude of current -Ig2 can be output at 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 .

[0065] Thus, the waveform shape changing unit 340 can divide at least one of the on-period and off-period of the switching element 311a into two or more periods based on the control signal output from the waveform shape control signal output unit 420, and change the gate current I G The amplitude of the gate current I is changed to a different size. In addition, the waveform shape changing unit 340 includes a plurality of transistors, and the number of transistors to be operated is changed based on the control signal output from the waveform shape control signal output unit 420, thereby being able to change the gate current I G Amplitude.

[0066] In addition, the waveform shape changing unit 340 can change the gate current I GThe waveform shape changing unit 340 can change the switching waveform to a different waveform shape according to each switching cycle of the switching element 311a during the operation of the power conversion device 1. In this case, the waveform shape control signal output unit 420 can change the waveform shape of the switching waveform of the switching element 311a according to the same cycle as the switching cycle of the switching element 311a. The waveform shape control signal output unit 420 can also change the waveform shape of the switching waveform of the switching element 311a according to a cycle that is a positive integer multiple of the switching cycle of the switching element 311a.

[0067] In addition, regarding the structure of the waveform shape changing unit 340, Figure 7 The structure of the waveform shape changing unit 340 shown is an example and is not limited thereto. In this way, the waveform shape changing unit 340 can adjust the switching speed of the switching element 311a more finely by digital control based on multiple MOS (Metal Oxide Semiconductor) compared with the analog control of physically switching the gate resistance described in Patent Document 1. In addition, the waveform shape changing unit 340 can also use transistors other than MOS for the transistors used internally.

[0068] In the above example, the waveform shape changing unit 340 changes the number of PMOS or NMOS to be operated according to the acquired control signal, and changes the gate current I corresponding to the number of PMOS or NMOS to be operated. G The waveform shape changing unit 340 may also store the gate current I corresponding to the control signal in advance. G The gate current I is output according to the output pattern, i.e., waveform shape, corresponding to the acquired control signal. G In addition, the waveform shape changing unit 340 may also store in advance the control signal obtained in the past and the gate current I when the control signal was obtained in the past. G When the same control signal is obtained, the gate current I is output according to the stored output style, that is, the waveform shape. G The waveform shape changing unit 340 stores the gate current I corresponding to the control signal in advance. G The output style, i.e. waveform shape, can reduce the output gate current I G processing load at the time.

[0069] In addition, Figure 7 In the example of FIG. 1 , the waveform shape changing unit 340 changes the gate current I GThe waveform shape changing unit 340 can adjust the switching speed of the switching element 311a and change the waveform shape of the switching waveform of the switching element 311a as the driving signal output to the switching element 311a, but is not limited to this. The waveform shape changing unit 340 can set the driving signal output to the switching element 311a to the gate voltage V G , by changing the gate voltage V G , similarly, the switching speed of the switching element 311a is adjusted to change the waveform shape of the switching waveform of the switching element 311a.

[0070] Thus, the waveform shape changing unit 340 can divide at least one of the on-period and off-period of the switching element 311a into two or more periods based on the control signal output from the waveform shape control signal output unit 420, and change the gate voltage V for the switching element 311a to V in each of the divided periods. G The amplitude of the waveform changer 340 is changed to a different size. In addition, the waveform changer 340 includes a plurality of transistors, and the number of transistors to be operated is changed based on the control signal output from the waveform control signal output unit 420, thereby being able to change the gate voltage V G Amplitude.

[0071] Fig.12 1 is a flowchart showing an operation of changing the waveform shape of the switching waveform 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 pulse generation unit 410 generates a basic pulse 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 to 505 (step S1). In this way, in the control unit 400, the basic pulse generation unit 410 generates a basic pulse based on the state quantity obtained from the state quantity detection units 501 to 505, 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 pulse generation unit 410 outputs the generated basic pulse to the waveform shape control signal output unit 420.

[0072] The waveform shape control signal output unit 420 sets a waveform shape for changing the waveform shape of the switching waveform of the switching elements 311a to 311f of the inverter 310 based on the basic pulse obtained from the basic pulse generating unit 410 and the state quantity obtained from the state quantity detecting units 501 to 505. In this way, in the control unit 400, the waveform shape control signal output unit 420 sets the waveform shape of the switching waveform 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 pulse generating unit 410 based on the state quantity obtained from the state quantity detecting units 501 to 505. The waveform shape control signal output unit 420 outputs a control signal that can change the size and output timing of the drive signal according to the set waveform shape to the waveform shape changing unit 340 (step S2).

[0073] The waveform shape changing unit 340 changes the gate current I output to the switching elements 311a to 311f of the inverter 310 based on the control signal obtained from the waveform shape control signal output unit 420. G The waveform shape of the gate current I after the waveform shape change is changed, that is, the waveform shape of the switching waveform of the switching elements 311a to 311f (step S3). G The output is to the switching elements 311 a to 311 f of the inverter 310 .

[0074] Next, the hardware configuration of the control unit 400 included in the power conversion device 1 will be described. Fig.13 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 .

[0075] 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).

[0076] As described above, according to the present embodiment, in the power conversion device 1, the waveform shape control signal output unit 420 of the control unit 400 outputs a control signal for changing the switching waveform of the switching elements 311a to 311f through the waveform shape change unit 340 of the inverter 310 based on the state quantity detected by the state quantity detection units 501 to 505. The waveform shape change unit 340 of the inverter 310 changes the gate current I output to the switching elements 311a to 311f based on the control signal output from the waveform shape control signal output unit 420. G Or gate voltage V G , thereby changing the waveform shape of the switching waveform of the switching elements 311a to 311f. As a result, the power conversion device 1 can change the switching speed of the switching elements 311a to 311f while suppressing the increase in circuit scale. The power conversion device 1 finely adjusts the gate current I output to the switching elements 311a to 311f during one switching period. G Or gate voltage V G , it is possible to realize the waveform shape of the switching waveform of the switching elements 311 a to 311 f which cannot be realized in the method of Patent Document 1 and the like.

[0077] Implementation method 2.

[0078] In the first embodiment, the waveform shape of the switching waveform of the switching elements 311a to 311f of the inverter 310 is changed in the power conversion device 1. In the second embodiment, the waveform shape of the switching waveform of the switching element 136 of the converter 130 is changed in the power conversion device 1.

[0079] Fig.14 1 is a diagram showing a configuration example of a power conversion device 1 according to Embodiment 2. The power conversion device 1 is connected to a commercial power supply 110 and a motor 314. The power conversion device 1 converts a first AC power of a power supply voltage Vs supplied from the commercial power supply 110 into a second AC power having a desired amplitude and phase, and supplies the second AC power to the motor 314. The power conversion device 1 includes a state quantity detection unit 501, a converter 130, a capacitor 210, a state quantity detection unit 502, an inverter 310, a state quantity detection unit 503, a state quantity detection unit 504, a state quantity detection unit 505, and a control unit 400. In addition, the motor drive device 2 is constituted by the power conversion device 1 and the motor 314.

[0080] Fig.14 The power conversion device 1 of the second embodiment shown in FIG. Figure 1 In the power conversion device 1 of the first embodiment shown, the waveform shape changer 340 is deleted from the inverter 310 and the drive circuit 350 is added, and the drive circuit 150 is deleted from the converter 130 and the waveform shape changer 140 is added. Fig.14 The power conversion device 1 of the second embodiment shown in FIG. Figure 1 The power conversion device 1 of the illustrated embodiment 1 changes the output destinations of the basic pulse generator 410 and the waveform control signal output unit 420. Specifically, the basic pulse generator 410 outputs the basic pulse for controlling the operation of the switching element 136 of the converter 130 to the waveform control signal output unit 420, and outputs the basic pulse for controlling the operation of the switching elements 311a to 311f of the inverter 310 to the inverter 310. In addition, the waveform control signal output unit 420 outputs the control signal for controlling the operation of the waveform changer 140 to the waveform changer 140.

[0081] In the inverter 310 , the drive circuit 350 generates a drive signal for actually driving the switching elements 311 a to 311 f based on the basic pulse generated by the basic pulse generating unit 410 of the control unit 400 .

[0082] In the present embodiment, the waveform control signal output unit 420 sets the waveform shape of the switching waveform of the switching element 136 when the switching waveform of the switching element 136 is changed by the waveform shape change unit 140 of the converter 130 based on the state quantity detected by the state quantity detection units 501 to 505, and outputs a control signal indicating the set waveform shape. Specifically, the waveform control signal output unit 420 controls the magnitude of the drive signal output to the switching element 136 and the timing of outputting the drive signal by the waveform shape change unit 140 of the converter 130 in order to actually drive the switching element 136 when the switching element 136 is turned on and off based on the basic pulse for controlling the operation of the switching element 136 of the converter 130 generated by the basic pulse generation unit 410. The waveform control signal output unit 420 outputs the control signal for controlling the operation of the waveform shape change unit 140 to the waveform shape change unit 140.

[0083] The waveform shape changing unit 140 can change the waveform shape of the switching waveform of the switching element 136. The waveform shape changing unit 140 can output two or more waveform shapes as the waveform shape of the switching waveform of the switching element 136. Fig.14 As shown in FIG. 1 , the waveform shape changing unit 140 is included in the inverter 130, and the inverter 130 is a power converter including a switching element 136. The structure of the waveform shape changing unit 140 is similar to Figure 7 The waveform shape changer 340 of the first embodiment shown in FIG. 1 has the same structure. That is, the waveform shape changer 140 and the switch element 136 are composed of one digital gate driver module. In addition, the waveform shape changer 140 can also adjust the gate voltage V output to the switch element 136 in the same manner as the waveform shape changer 340. G Instead of outputting the gate current I to the switching element 136 G as the driving signal.

[0084] Thus, the waveform shape changing unit 140 can divide at least one of the on-period and off-period of the switching element 136 into two or more periods based on the control signal output from the waveform shape control signal output unit 420, and change the gate current I G Or gate voltage V G The amplitude of the gate current I is changed to a different size. In addition, the waveform shape changing unit 140 includes a plurality of transistors, and the number of transistors to be operated is changed based on the control signal output from the waveform shape control signal output unit 420, thereby being able to change the gate current I G Or gate voltage V GThus, the power conversion device 1 can change the waveform shape of the switching waveform of the switching element 136 of the converter 130 by using the waveform shape control signal output unit 420 and the waveform shape change unit 140 by performing the same operation as that of the first embodiment.

[0085] As described above, according to the present embodiment, in the power conversion device 1, the waveform shape control signal output unit 420 of the control unit 400 outputs a control signal for changing the switching waveform of the switching element 136 through the waveform shape change unit 140 of the converter 130 based on the state quantity detected by the state quantity detection units 501 to 505. The waveform shape change unit 140 of the converter 130 changes the gate current I output to the switching element 136 based on the control signal output from the waveform shape control signal output unit 420. G Or gate voltage V G , thereby changing the waveform shape of the switching waveform of the switching element 136. The waveform shape changing unit 140 can change the waveform shape of the switching waveform of the switching element 136 in the same way as the waveform shape changing unit 340 of the first embodiment changes the waveform shape of the switching waveform of the switching element 311a. As a result, the power conversion device 1 can change the switching speed of the switching element 136 while suppressing an increase in the circuit scale. The power conversion device 1 finely adjusts the gate current I output to the switching element 136 within one switching period. G Or gate voltage V G , it is possible to realize a waveform shape of the switching waveform of the switching element 136 which cannot be realized in the method of Patent Document 1 and the like.

[0086] In the present embodiment, the structure of the inverter 130 to which the waveform shape of the switching element is to be changed is not limited to Fig.14 Example. Fig.15 This is a first diagram showing a rectifying portion of the inverter 130 included in the power conversion device 1 according to the second embodiment. Fig.16 This is a second diagram showing a rectifying portion of the inverter 130 included in the power conversion device 1 according to the second embodiment. Fig.17 FIG. 3 is a diagram showing a rectifying portion of the inverter 130 included in the power conversion device 1 according to the second embodiment. Figures 15 to 17 In the figure, only Fig.14 The waveform shape changing unit 140 is omitted. Fig.15 As shown in FIG. 1 , in a configuration where the converter 130 includes the reactor 135, the switching elements 136a to 136d, and the freewheeling diodes 137a to 137d, the waveform shape changing unit 140 may also change the waveform shape of the switching waveform of the switching elements 136a to 136d. Fig.16As shown in FIG. 1 , in a configuration where the converter 130 includes a reactor 135, rectifier elements 131 to 134, a switch element 136, a flyback diode 137, and rectifier elements 131a to 134a, the waveform shape changer 140 may also change the waveform shape of the switching waveform of the switch element 136. Fig.17 As shown, in a structure in which the connected commercial power supply is a three-phase AC power supply 110a and the converter 130 has reactors 135a~135c, rectifier elements 131a~131c, switching elements 136a~136c and freewheeling diodes 137a~137c, the waveform shape changer 140 can also change the waveform shape of the switching waveform of the switching elements 136a~136c.

[0087] Implementation method 3.

[0088] In the first embodiment, a case where the waveform shape of the switching waveform of the switching elements 311a to 311f of the inverter 310 is changed in the power conversion device 1 is described. In the second embodiment, a case where the waveform shape of the switching waveform of the switching element 136 of the converter 130 is changed in the power conversion device 1 is described. In the third embodiment, a case where the waveform shape of the switching waveform of the switching elements 311a to 311f of the inverter 310 is changed in the power conversion device 1 and the waveform shape of the switching waveform of the switching element 136 of the converter 130 is changed is described.

[0089] Fig.18 1 is a diagram showing a configuration example of a power conversion device 1 according to Embodiment 3. The power conversion device 1 is connected to a commercial power supply 110 and a motor 314. The power conversion device 1 converts a first AC power of a power supply voltage Vs supplied from the commercial power supply 110 into a second AC power having a desired amplitude and phase, and supplies the second AC power to the motor 314. The power conversion device 1 includes a state quantity detection unit 501, a converter 130, a capacitor 210, a state quantity detection unit 502, an inverter 310, a state quantity detection unit 503, a state quantity detection unit 504, a state quantity detection unit 505, and a control unit 400. In addition, the motor drive device 2 is constituted by the power conversion device 1 and the motor 314.

[0090] Fig.18 The power conversion device 1 of the third embodiment shown in FIG. Figure 1 In the power conversion device 1 of the first embodiment shown, the drive circuit 150 is deleted from the inverter 130 and a waveform shape changing unit 140 is added. Fig.18 The power conversion device 1 of the third embodiment shown in FIG. Figure 1The power conversion device 1 of the illustrated embodiment 1 changes the output destinations of the basic pulse generator 410 and the waveform control signal output unit 420. Specifically, the basic pulse generator 410 outputs the basic pulse for controlling the operation of the switching elements 311a to 311f of the inverter 310 to the waveform control signal output unit 420, and outputs the basic pulse for controlling the operation of the switching element 136 of the converter 130 to the waveform control signal output unit 420. In addition, the waveform control signal output unit 420 outputs the control signal for controlling the operation of the waveform changer 340 to the waveform changer 340, and outputs the control signal for controlling the operation of the waveform changer 140 to the waveform changer 140.

[0091] In the present embodiment, the waveform shape control signal output unit 420 performs the operation described in the second embodiment together with the operation described in the first embodiment. In addition, in the present embodiment, the waveform shape change unit 340 performs the same operation as the operation described in the first embodiment, and the waveform shape change unit 140 performs the same operation as the operation described in the second embodiment. Thus, the power conversion device 1 can change the waveform shape of the switching waveform of the switching elements 311a to 311f of the inverter 310 by using the waveform shape control signal output unit 420 and the waveform shape change unit 340 by performing the same operation as the first embodiment. In addition, the power conversion device 1 can change the waveform shape of the switching waveform of the switching element 136 of the converter 130 by using the waveform shape control signal output unit 420 and the waveform shape change unit 140 by performing the same operation as the second embodiment.

[0092] In addition, in the present embodiment, the power conversion device 1 can also perform the following control: at a certain timing, one of the waveform shape changers 140 and 340 changes the waveform shape of the switching waveform of the switching element, while the other does not change the waveform shape of the switching waveform of the switching element. In the present embodiment, the switching element as the object of the switching waveform of the switching element changed by the waveform shape changer 140 and 340 of the power conversion device 1 is one or more switching elements included in at least one of the one or more power converters that perform power conversion in the power conversion device 1.

[0093] As described above, according to the present embodiment, in the power conversion device 1, the waveform shape control signal output unit 420 of the control unit 400 outputs a control signal when the waveform shape change unit 340 of the inverter 310 changes the switching waveform of the switching elements 311a to 311f based on the state quantity detected by the state quantity detection units 501 to 505, and outputs a control signal when the waveform shape change unit 140 of the converter 130 changes the switching waveform of the switching element 136. The waveform shape change unit 340 of the inverter 310 changes the gate current I output to the switching elements 311a to 311f based on the control signal output from the waveform shape control signal output unit 420. G Or gate voltage V G , thereby changing the waveform shape of the switching waveform of the switching elements 311a to 311f. In addition, the waveform shape changing unit 140 of the inverter 130 changes the gate current I output to the switching element 136 based on the control signal output from the waveform shape control signal output unit 420. G Or gate voltage V G , thereby changing the waveform shape of the switching waveform of the switching element 136. As a result, the power conversion device 1 can change the switching speed of the switching elements 311a to 311f and the switching element 136 while suppressing the increase in circuit scale. The power conversion device 1 finely adjusts the gate current I output to the switching elements 311a to 311f and the switching element 136 within one switching period. G Or gate voltage V G , it is possible to realize the waveform shapes of the switching waveforms of the switching elements 311 a to 311 f and the switching element 136 which cannot be realized in the method of Patent Document 1 and the like.

[0094] Implementation method 4.

[0095] A description will be given of a case where an adaptive observer is applied as sensorless control of the motor 314 in the power conversion device 1 of Embodiments 1 to 3. Specifically, the description will be given by taking the power conversion device 1 of Embodiment 1 as an example.

[0096] Fig.19 It is a diagram showing a configuration example of a power conversion device 1 according to a fourth embodiment. Fig.19 The power conversion device 1 of the fourth embodiment shown in FIG. Figure 1 The power conversion device 1 of the illustrated first embodiment is provided with an additional speed estimation device 101 . Fig. 20 1 is a diagram showing a configuration example of a speed estimation device 101 provided in a power conversion device 1 according to Embodiment 4. The speed estimation device 101 estimates the rotation speed of the motor 314 using a voltage vector and a current vector applied to the motor 314 by an adaptive observer method, and obtains the estimated angular velocity ω^. r And output.

[0097] The speed estimation device 101 includes a model deviation calculation unit 11 that calculates the estimated angular velocity ω based on the voltage vector, the current vector, and the estimated angular velocity ω. r , to calculate the model deviation ε; and a first angular velocity estimation unit 21, which, based on the model deviation ε, calculates the low-frequency component of the actual angular velocity including the DC component as the first estimated angular velocity ω ^ r1 In addition, the velocity estimation device 101 includes a second angular velocity estimation unit 22 that calculates the high-frequency component of the actual angular velocity as a second estimated angular velocity ω^ based on a specific high-frequency component included in the model deviation ε. r2 And an adder 23, which is calculated by the second estimated angular velocity ω ^ r2 and the first estimated angular velocity ω r1 Add them together to calculate the estimated angular velocity ω^ r The velocity estimation device 101 is characterized in that it includes a second angular velocity estimation unit 22. The velocity estimation device 101 calculates the first estimated angular velocity ω^ r1 and the second estimated angular velocity ω r2 The sum of the values ​​is used as the estimated angular velocity ω r The result is fed back to the model deviation calculation unit 11 .

[0098] The model deviation calculation unit 11 includes a current estimator 12 that estimates the angular velocity ω^ based on the voltage vector, current vector, and angular velocity ω of the motor 314. r , calculating and outputting the estimated magnetic flux vector and the estimated current vector; a subtractor 13, which subtracts the current vector from the estimated current vector, calculating and outputting the current deviation vector; and a deviation calculator 14, which takes the current deviation vector as input, extracts the orthogonal component of the estimated magnetic flux vector as a scalar, and outputs the value as the model deviation ε. As a method of extracting the orthogonal component of the estimated magnetic flux vector as a scalar, there are known methods of performing coordinate transformation of the current deviation vector on two rotation axes and a method of calculating the size of the outer product value of the current deviation vector and the estimated magnetic flux vector.

[0099] The current estimator 12 estimates the current and the magnetic flux based on the state equation of the motor 314. Here, it is assumed that the motor 314 is a conventional embedded magnet type synchronous AC motor, but even if the motor 314 is other than the embedded magnet type synchronous AC motor, as long as the state equation is established, the current estimator 12 can also perform current estimation by the same method. The motor 314 other than the embedded magnet type synchronous AC motor can be exemplified by a surface magnet type synchronous motor, an induction motor, etc. In addition, in this embodiment, the rotary motor is described, but the same technology can also be applied to the direct-acting motor. This is because it can be interpreted as "the direct-acting motor is a rotary motor with an infinite rotor radius".

[0100] In this way, the power conversion device 1 can apply the adaptive observer as the sensorless control of the motor 314 .

[0101] Implementation method 5.

[0102] A case where control is performed in the power conversion device 1 of Embodiments 1 to 3 to suppress degradation of the capacitor 210 for smoothing and suppress increase in size of the device will be described. Specifically, the power conversion device 1 of Embodiment 1 will be described as an example.

[0103] Fig.21 It is a diagram showing a configuration example of a power conversion device 1 according to a fifth embodiment. Fig.21 The structure of the power conversion device 1 of the fifth embodiment shown is similar to Figure 1 The inverter 130 has the same structure as the power conversion device 1 of the illustrated embodiment 1. The inverter 130 is a rectifying unit that includes a bridge circuit composed of rectifying elements 131 to 134 and rectifies the first AC power of the power supply voltage Vs supplied from the commercial power supply 110 and outputs the rectified power.

[0104] In the present embodiment, the control unit 400 controls the operation of the inverter 310 so that the second AC power including the pulsation corresponding to the pulsation of the power flowing from the converter 130 as the rectifier to the capacitor 210 is output from the inverter 310 to the motor 314 as the load. The pulsation corresponding to the pulsation of the power flowing into the capacitor 210 is, for example, a pulsation that varies according to the frequency of the pulsation of the power flowing into the capacitor 210. Thus, the control unit 400 suppresses the current flowing into the capacitor 210. In addition, the control unit 400 may not use all the detection values ​​obtained from each detection unit, but may use a part of the detection values ​​for control.

[0105] The operation of the control unit 400 provided in the power conversion device 1 is described. In the present embodiment, in the power conversion device 1, the load generated by the inverter 310 and the motor 314 can be regarded as a constant load. When observing the current output from the capacitor 210, it is assumed that a constant current load is connected to the capacitor 210 for the following description. Here, Fig.21 As shown, the current flowing from the converter 130 is set as current I1, the current flowing to the inverter 310 is set as current I2, and the current flowing from the capacitor 210 is set as current I3. Current I2 becomes a current obtained by combining current I1 and current I3. Current I3 can be expressed as the difference between current I2 and current I1, that is, current I2-current I1. For current I3, the discharge direction of the capacitor 210 is set as the positive direction, and the charging direction of the capacitor 210 is set as the negative direction. That is, sometimes the current flows into the capacitor 210, and sometimes the current flows out of the capacitor 210.

[0106] Fig. 22 This is a diagram showing examples of currents I1 to I3 and capacitor voltage Vdc of capacitor 210 when the current output from converter 130 is smoothed by capacitor 210 and current I2 flowing to inverter 310 becomes constant as a comparative example. Current I1, current I2, current I3, and capacitor voltage Vdc of capacitor 210 generated in response to current I3 are shown in order from the top. The vertical axis of currents I1, I2, and I3 represents current values, and the vertical axis of capacitor voltage Vdc represents voltage values. The horizontal axis represents time t in its entirety. In addition, the carrier component of inverter 310 is actually superimposed on currents I2 and I3, but this is omitted here. The same shall apply hereinafter. As Fig. 22 As shown, in the power conversion device 1, it is assumed that when the current I1 flowing from the converter 130 is sufficiently smoothed by the capacitor 210, the current I2 flowing to the inverter 310 becomes a constant current value. However, a large current I3 flows in the capacitor 210, which becomes a major cause of degradation. Therefore, in the present embodiment, in the power conversion device 1, the control unit 400 controls the current I2 flowing to the inverter 310, that is, controls the operation of the inverter 310, so as to reduce the current I3 flowing to the capacitor 210.

[0107] Fig.23 This is a diagram showing an example of each current I1 to I3 and a capacitor voltage Vdc of the capacitor 210 when the control unit 400 of the power conversion device 1 of the fifth embodiment controls the operation of the inverter 310 to reduce the current I3 flowing to the capacitor 210. From the top, the current I1, the current I2, the current I3, and the capacitor voltage Vdc of the capacitor 210 generated by the current I3 are shown in order. The vertical axis of the currents I1, I2, and I3 represents the current value, and the vertical axis of the capacitor voltage Vdc represents the voltage value. The horizontal axis represents the time t. The control unit 400 of the power conversion device 1 controls the operation of the inverter 310 so that Fig.23 The current I2 shown flows to the inverter 310, thereby Fig. 22 Compared with the example, the frequency component of the current flowing from the converter 130 to the capacitor 210 can be reduced, and the current I3 flowing to the capacitor 210 can be reduced. Specifically, the control unit 400 controls the operation of the inverter 310 so that the current I2 including the pulsating current whose main component is the frequency component of the current I1 flows to the inverter 310.

[0108] In this way, in the power conversion device 1, the control unit 400 controls the operation of the inverter 310 as the power converter so that the pulsation corresponding to the state quantity detected by the state quantity detection units 501, 502, and 503 is superimposed from the inverter 310 on the driving pattern of the motor 314 connected to the inverter 310, thereby suppressing the charging and discharging current of the capacitor 210. As a result, the power conversion device 1 can suppress the degradation of the capacitor 210 for smoothing.

[0109] Implementation method 6.

[0110] The following description will describe a case where the power conversion device 1 of Embodiments 1 to 3 is controlled to suppress the variation of the DC voltage even when the number of switching operations of the short-circuit portion that short-circuits the commercial power supply 110 as the AC power supply is changed in accordance with the load conditions. Specifically, the power conversion device 1 of Embodiment 1 is described as an example.

[0111] Fig.24 It is a diagram showing a configuration example of a power conversion device 1 according to a sixth embodiment. Fig.24 The power conversion device 1 of the sixth embodiment shown in FIG. Figure 1 The power conversion device 1 of the illustrated embodiment 1 has the converter 130 and the capacitor 210 deleted, and has the reactor 135, the rectifier 170, and the short-circuit 30 added. The rectifier 170 includes a rectifier circuit composed of four rectifier elements 131 to 134, and a capacitor 210 connected between the output ends of the rectifier circuit and smoothing the voltage of the full-wave rectified waveform output from the rectifier circuit. The rectifier 170 rectifies the first AC power supplied from the commercial power supply 110 and outputs it.

[0112] The short-circuit section 30 short-circuits the commercial power source 110 via the reactor 135. The short-circuit section 30 includes a diode bridge 31 connected in parallel to the commercial power source 110 via the reactor 135, and a short-circuit element 32 connected to two output ends of the diode bridge 31. When the short-circuit element 32 is a metal oxide film semiconductor field effect transistor, the short-circuit element 32 has a gate connected to the control section 400, and the short-circuit element 32 is turned on and off according to a drive signal from the control section 400. When the short-circuit element 32 is turned on, the commercial power source 110 is short-circuited via the reactor 135 and the diode bridge 31.

[0113] The control unit 400 controls the short-circuiting operation of the short-circuiting unit 30. The control unit 400 controls the on / off switching of the short-circuiting element 32 by the current open-loop control in the short-circuiting operation mode, so that the short-circuiting unit 30 is short-circuited at least twice in a half cycle of the power supply. The control unit 400 short-circuits the short-circuiting unit 30 at least twice in a half cycle of the commercial power supply 110 based on the load condition. Thus, even when the number of switching times of the short-circuiting unit 30 that short-circuits the commercial power supply 110 is changed in accordance with the load condition, the power conversion device 1 can suppress the variation of the DC voltage.

[0114] Implementation method 7.

[0115] Fig.25 Refrigeration cycle application device 900 of embodiment 7 is a diagram showing a structural example. Refrigeration cycle application device 900 of embodiment 7 includes power conversion device 1 described in embodiment 1. Refrigeration cycle application device 900 of embodiment 7 can also include power conversion device 1 described in embodiments 2 to 6. Refrigeration cycle application device 900 of embodiment 7 can be applied to products including refrigeration cycles such as air conditioners, refrigerators, freezers, and heat pump water heaters. Fig.25 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.

[0116] In the refrigeration cycle application equipment 900 , 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 are installed via the refrigerant pipe 912 .

[0117] A compression mechanism 904 for compressing the refrigerant and a motor 314 for operating the compression mechanism 904 are provided inside the compressor 315 .

[0118] 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.

[0119] 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.

[0120] During cooling operation, as shown by the dotted 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.

[0121] 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 to expand it.

[0122] 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 5 As 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 switching 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 switching speed of the switching elements 311a to 311f and the like.

[0123] Here, in the power conversion device 1 provided by the refrigeration cycle application device 900, when the switching speed of the digital gate driver module composed of the waveform shape changer 340 and the switching elements 311a to 311f included in the inverter 310 is high, the surge voltage becomes large 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 switching speed of the digital gate driver module provided by 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 switching speed of the digital gate driver module provided by the power conversion device 1. The refrigeration cycle application device 900 can reduce the surge voltage by slowing down the switching speed of the digital gate driver module, suppress the generation of discharge caused by electromagnetic noise, and thus, even if the refrigerant leaks from the refrigeration cycle application device 900, it can prevent combustion.

[0124] 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.

[0125] 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.

[0126] Description of Reference Numerals

[0127] 1 power conversion device, 2 motor drive device, 11 model deviation calculation unit, 12 current estimator, 13 subtractor, 14 deviation calculation unit, 21 first angular velocity estimation unit, 22 second angular velocity estimation unit, 23 adder, 30 short-circuit unit, 31 diode bridge, 32 short-circuit element, 101 velocity estimation device, 110, 110a commercial power supply, 130 inverter, 131-134, 131a-134a, 131b, 131c rectifying element, 135, 135a-135c reactor, 136, 136a-136d, 311a-311f switching element, 13 7. 137a~137d, 312a~312f freewheeling diodes, 138 diodes, 140, 340 waveform shape changing units, 150, 350 drive circuits, 170 rectification units, 210 capacitors, 310 inverters, 314 motors, 315 compressors, 400 control units, 410 basic pulse generating units, 420 waveform shape control signal output units, 501~505 state quantity detecting units, 900 refrigeration cycle application equipment, 902 four-way valves, 904 compression mechanisms, 906 indoor heat exchangers, 908 expansion valves, 910 outdoor heat exchangers, and 912 refrigerant piping.

Claims

1. A power conversion device for performing power conversion, wherein: The power conversion device comprises: One or more switching elements included in at least one of the one or more power converters that perform power conversion; a waveform shape changing unit capable of changing the waveform shape of the switching waveform of the switching element; a state quantity detecting unit for detecting a state quantity indicating an operating state of the power conversion device; as well as A waveform shape control signal output unit outputs a control signal when the switching waveform of the switching element is changed by the waveform shape change unit based on the state amount.

2. The power conversion device according to claim 1, wherein: The waveform shape changing unit can divide at least one of the on-period and off-period of the switching element into two or more periods for the waveform shape of the switching waveform of the switching element based on the control signal output from the waveform shape control signal output unit, and change the amplitude of the gate current or gate voltage of the switching element to a different size in each of the divided periods.

3. The power conversion device according to claim 2, wherein: The waveform shape changing unit includes a plurality of transistors, and changes the number of the transistors to be operated based on the control signal output from the waveform shape control signal output unit to change the amplitude of the gate current or the gate voltage.

4. The power conversion device according to any one of claims 1 to 3, wherein: The waveform shape changing unit can change the switching waveform to a different waveform shape for each switching cycle of the switching element during the operation of the power conversion device.

5. The power conversion device according to any one of claims 1 to 4, wherein: The waveform shape control signal output unit changes the waveform shape of the switching waveform of the switching element at a cycle that is the same as a switching cycle of the switching element or a cycle that is a positive integer multiple of the switching cycle of the switching element.

6. The power conversion device according to any one of claims 1 to 5, wherein: The waveform shape control signal output unit changes the waveform shape of the switching waveform of the switching element so that the loss generated by the switching element is reduced while the noise generated by the switching element meets the specified requirements, or the waveform shape control signal output unit changes the waveform shape of the switching waveform of the switching element so that the noise generated by the switching element is reduced while the loss generated by the switching element meets the specified requirements.

7. The power conversion device according to any one of claims 1 to 6, wherein: The power converter including the switching element further includes the waveform shape changing unit. The power converter is an inverter, or a converter, or an inverter and a converter.

8. The power conversion device according to any one of claims 1 to 7, wherein: The power conversion device includes a speed estimation device, The speed estimation device comprises: a model deviation calculation unit that calculates a model deviation based on a voltage, a current, and an estimated angular velocity of the AC motor; a first angular velocity estimation unit that calculates a low-frequency component including a DC component of the actual angular velocity as a first estimated angular velocity based on the model deviation; a second angular velocity estimating unit that calculates a high-frequency component of the actual angular velocity as a second estimated angular velocity based on a specific high-frequency component included in the model deviation; as well as an adder that adds the first estimated angular velocity and the second estimated angular velocity, An added value of the first estimated angular velocity and the second estimated angular velocity is fed back to the model deviation calculation unit as the estimated angular velocity.

9. The power conversion device according to any one of claims 1 to 7, wherein: The power conversion device comprises: a rectifier unit that rectifies AC power supplied from a commercial power source; a capacitor connected to an output terminal of the rectifying unit; and A control unit, which includes the waveform shape control signal output unit, controls the operation of the inverter serving as the power converter so that a pulsation corresponding to the state quantity detected by the state quantity detection unit is superimposed from the inverter to a driving pattern of a motor connected to the inverter, thereby suppressing a charge and discharge current of the capacitor.

10. The power conversion device according to any one of claims 1 to 7, wherein: The power conversion device comprises: a rectifier unit that rectifies AC power supplied from a commercial power source; a short-circuiting section that short-circuits the commercial power supply via a reactor; and A control unit, which includes the waveform shape control signal output unit, controls the short-circuiting action of the short-circuiting unit, The control unit short-circuits the short-circuit unit at least twice within a half cycle of the commercial power supply based on a load condition.

11. A motor drive device, wherein: The motor drive device includes the power conversion device according to any one of claims 1 to 10.

12. A refrigeration cycle application device, wherein: The refrigeration cycle application equipment includes the power conversion device according to any one of claims 1 to 10.

13. The refrigeration cycle application device according to claim 12, wherein: The refrigerant used is any of R1234yf, R1234ze(E), R1243zf, HFO1123, HFO1132(E), R1132a, CF3I, R290, R463A, R466A, R454A, R454B, and R454C.

14. The refrigeration cycle application device according to claim 13, wherein: A switching speed of a digital gate driver module included in the power conversion device is set according to the combustibility of the refrigerant.

Images