WO2023238291A1

WO2023238291A1 - Power conversion device, motor drive device, and refrigeration cycle application device

Info

Publication number: WO2023238291A1
Application number: PCT/JP2022/023161
Authority: WO
Inventors: 貴昭 ▲高▼原; 遥松尾; 知宏沓木; 浩一有澤; 亮祐小林; 泰章古庄
Original assignee: 三菱電機株式会社
Priority date: 2022-06-08
Filing date: 2022-06-08
Publication date: 2023-12-14

Abstract

A power conversion device (1) for performing power conversion comprises: one or more switching elements included in at least one power converter among one or more power converters for performing power conversion; a waveform shape change unit capable of changing the waveform shapes of the switching waveforms of the switching elements; state quantity detection units (501 to 505) detecting state quantities indicating the operation states of the power conversion device (1); and a waveform shape control signal output unit (420) outputting a control signal used when the waveform shape change unit changes the switching waveforms of the switching elements in accordance with the state quantities.

Description

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

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

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

Japanese Patent Application Publication No. 2012-200042

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

The present disclosure has been made in view of the above, and aims to provide a power converter device that can change the switching speed of a switching element while suppressing an increase in circuit scale.

In order to solve the above-mentioned problems and achieve the objectives, the present disclosure is a power conversion device that performs power conversion. The power conversion device includes one or more switching elements included in at least one power converter among the one or more power converters that perform power conversion, and a waveform shape changing unit that can change the waveform shape of a switching waveform of the switching element. , a state quantity detection unit that detects a state quantity indicating the operating state of the power converter, and a waveform shape control signal that outputs a control signal when changing the switching waveform of the switching element in the waveform shape changing unit according to the state quantity. An output section.

The power conversion device according to the present disclosure has the effect of being able to change the switching speed of the switching element while suppressing an increase in circuit scale.

A diagram showing a configuration example of a power conversion device according to Embodiment 1. A diagram showing an example of turn-on Joule loss, turn-on current, and turn-on voltage when the switching speed of the switching element of the inverter is slowed down in the power conversion device according to Embodiment 1. A diagram showing an example of turn-on Joule loss, turn-on current, and turn-on voltage when the switching speed of the switching element of the inverter is increased in the power conversion device according to Embodiment 1. Diagram showing an example of the relationship between noise and loss generated in general switching elements The first diagram showing the effect obtained by changing the switching speed of the switching element of the inverter in the power conversion device according to the first embodiment. A second diagram illustrating the effect obtained by changing the switching speed of the switching element of the inverter in the power conversion device according to Embodiment 1. A diagram showing a configuration example of a waveform shape changing section of the power conversion device according to Embodiment 1. The first diagram showing the relationship between the gate current output by the waveform shape changing unit and the gate voltage indicating the rising speed of the switching element in the power conversion device according to the first embodiment. A second diagram showing the relationship between the gate current output by the waveform shape changing unit and the gate voltage indicating the rising speed of the switching element in the power conversion device according to the first embodiment. 3 is a third diagram showing the relationship between the gate current output by the waveform shape changing unit and the gate voltage indicating the rising speed of the switching element in the power converter according to the first embodiment; FIG. A diagram showing an example of the relationship between the basic pulse output by the basic pulse generation unit and the gate current output by the waveform shape changing unit in the power conversion device according to Embodiment 1. Flowchart showing the operation of changing the waveform shape of the switching waveform of the switching element in the power conversion device according to Embodiment 1 A diagram illustrating an example of a hardware configuration that implements a control unit included in the power conversion device according to Embodiment 1. A diagram showing a configuration example of a power conversion device according to Embodiment 2 A first diagram showing a rectifying part of a converter included in a power conversion device according to Embodiment 2. A second diagram showing a rectifying part of a converter included in a power conversion device according to a second embodiment. A third diagram showing a rectifying part of a converter included in the power conversion device according to Embodiment 2. A diagram showing a configuration example of a power conversion device according to Embodiment 3 A diagram showing a configuration example of a power conversion device according to Embodiment 4 A diagram showing a configuration example of a speed estimating device included in a power conversion device according to Embodiment 4. A diagram showing a configuration example of a power conversion device according to Embodiment 5 As a comparative example, a diagram showing examples of each current and the capacitor voltage of the capacitor when the current output from the rectifier is smoothed with a capacitor and the current flowing to the inverter is kept constant. 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 Embodiment 5 controls the operation of the inverter to reduce the current flowing to the capacitor. A diagram showing a configuration example of a power conversion device according to Embodiment 6 A diagram showing a configuration example of a refrigeration cycle application device according to Embodiment 7

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

Embodiment 1.
FIG. 1 is a diagram showing a configuration example of a power conversion device 1 according to the first embodiment. Power conversion device 1 is connected to commercial power source 110 and motor 314. The power conversion device 1 converts the first AC power of the power supply voltage Vs 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. Although the commercial power source 110 is a single-phase AC power source in the example of FIG. 1, it may be a three-phase AC power source. The power conversion device 1 includes a state quantity detection section 501, a converter 130, a capacitor 210, a state quantity detection section 502, an inverter 310, a state quantity detection section 503, a state quantity detection section 504, and a state quantity detection section. 505 and a control unit 400. Note that the power conversion device 1 and the motor 314 constitute a motor drive device 2.

The state quantity detection unit 501 detects a state quantity indicating the operating state of the power conversion device 1. The state quantity detection unit 501 detects, for example, the voltage value of the AC power at the power supply voltage Vs supplied from the commercial power supply 110 to the converter 130, the current value of the AC power at the power supply voltage Vs supplied from the commercial power supply 110 to the converter 130, etc. To detect.

The converter 130 is a power converter that converts AC power of power supply voltage Vs supplied from the commercial power supply 110 into DC power. Converter 130 includes rectifying elements 131 to 134, a reactor 135, a switching element 136, a free wheel diode 137, a diode 138, and a drive circuit 150. The converter 130 has a bridge circuit configured by rectifying elements 131 to 134, rectifies the first AC power of the power supply voltage Vs supplied from the commercial power supply 110, and boosts and outputs the rectified DC power. . The drive circuit 150 generates a drive signal for actually driving the switching element 136 based on a basic pulse generated by a basic pulse generation unit 410 of the control unit 400, which will be described later. The switching element 136 is, for example, an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). or), bipolar transistors, etc., but are not limited to these. Note that the configuration of converter 130 is not limited to the example in FIG. 1. In converter 130, one or more of rectifying elements 131 to 134 may be configured with a switching element. Further, in the power conversion device 1 of the first embodiment shown in FIG. 1, the converter 130 may have only a rectification function and may not have a boost function. Further, when the commercial power source 110 is a three-phase AC power source, the converter 130 has a configuration including six rectifying elements.

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

The state quantity detection unit 502 detects a state quantity indicating the operating state of the power conversion device 1. The state quantity detection unit 502 detects, for example, the voltage value of the DC power supplied from the capacitor 210 to the inverter 310.

The inverter 310 is a power converter connected to both ends of the capacitor 210. Inverter 310 has switching elements 311a to 311f and free wheel diodes 312a to 312f. Inverter 310 turns on and off switching elements 311a to 311f under the control of control unit 400, converts the power output from converter 130 and capacitor 210 into second AC power having a desired amplitude and phase, that is, second AC power. Electric power is generated and output to motor 314. The switching elements 311a to 311f are, for example, IGBTs, 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 full bridge circuit, a single-phase bridge circuit, a half bridge circuit, or the like. Furthermore, in this embodiment, the inverter 310 includes a waveform shape changing section 340 that can change the waveform shape of the switching waveforms of the switching elements 311a to 311f. The waveform shape changing section 340 can output two or more waveform shapes as the waveform shapes of the switching waveforms of the switching elements 311a to 311f. In the example of FIG. 1, the waveform shape changing unit 340 is configured to be able to change the waveform shape of the switching waveform of the switching elements 311a to 311f, but the waveform shape of the switching waveform of at least one switching element among the switching elements 311a to 311f is The shape can be changed. Furthermore, the inverter 310 may be configured to include a waveform shape changing section 340 for each of the switching elements 311a to 311f. The detailed operation of the waveform shape changing section 340 will be described later.

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, the voltage value of the second AC power supplied from the inverter 310 to the motor 314, which is the load, and the current value of the second AC power, which is supplied from the inverter 310 to the motor 314, which is the load. Detect etc. The state quantity detection unit 504 detects a state quantity indicating the operating state of the power conversion device 1. The state quantity detection unit 504 detects, for example, the current value of the DC power supplied from the capacitor 210 to the inverter 310. 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, current flowing through the switching

elements

311b, 311d, and 311f.

Control unit 400 acquires the state quantities detected by state quantity detection units 501 to 505 from state quantity detection units 501 to 505, and controls and specifically controls the operations of converter 130 and inverter 310 based on the acquired state quantities. Specifically, it controls the on/off of switching element 136 of converter 130, and controls the on/off of switching elements 311a to 311f of inverter 310. The control section 400 includes a basic pulse generation section 410 and a waveform shape control signal output section 420.

The basic pulse generation unit 410 has a duty ratio according to the state quantities detected by the state quantity detection units 501 to 505, and generates a basic pulse for controlling the operation of the switching element 136 of the converter 130. Further, the basic pulse generation unit 410 has a duty ratio according to the state quantities detected by the state quantity detection units 501 to 505, and generates basic pulses for controlling the operation of the switching elements 311a to 311f of the inverter 310. do. The basic pulse is, for example, a PWM (Pulse Width Modulation) signal having a duty ratio according to the state quantities detected by the state quantity detection units 501 to 505. The basic pulse generation unit 410 outputs basic pulses to the converter 130 for controlling the operation of the switching elements 136 of the converter 130, and controls the waveform shape of the basic pulses for controlling the operations of the switching elements 311a to 311f of the inverter 310. The signal is output to the signal output section 420.

The waveform shape control signal output section 420 is a switching element used when changing the switching waveforms of the switching elements 311a to 311f in the waveform shape changing section 340 of the inverter 310 according to the state quantities detected by the state quantity detection sections 501 to 505. The waveform shapes of the switching waveforms 311a to 311f are set, and a control signal indicating the set waveform shape is output. Specifically, the waveform shape control signal output unit 420 turns on and off the switching elements 311a to 311f based on the basic pulse generated by the basic pulse generation unit 410 for controlling the operation of the switching elements 311a to 311f of the inverter 310. At this time, the waveform shape changing unit 340 of the inverter 310 controls the magnitude of the drive signal output to the switching elements 311a to 311f and the timing of outputting the drive signal in order to actually drive the switching elements 311a to 311f. The waveform shape control signal output section 420 outputs a control signal for controlling the operation of the waveform shape modification section 340 to the waveform shape modification section 340 . When the inverter 310 includes a waveform shape changing section 340 for each of the switching elements 311a to 311f, that is, six waveform shape changing sections 340, the control section 400 controls a waveform shape control signal output section 420 for each waveform shape changing section 340. In other words, the configuration may include six waveform shape control signal output sections 420.

In the example of FIG. 1, the control unit 400 acquires 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 converter 130 and the state quantity based on the obtained state quantities. Although the operation of the inverter 310 is controlled, the present invention is not limited thereto. Control unit 400 can control the operation of converter 130 and inverter 310 based on the state quantity acquired from at least one state quantity detection unit among state quantity detection units 501 to 505. In the power conversion device 1, the state quantity detection units 501 to 505, in the above-mentioned example, detect the voltage or current input to each component of the power conversion device 1, the voltage or current output from each component of the power conversion device 1, etc. was detected as a state quantity, but the detection target is not limited to these. Furthermore, the installation positions of the state quantity detection units 501 to 505 are not limited to the example shown in FIG. In the power conversion device 1, it is not necessary to arrange all the state quantity detection units 501 to 505 as shown in FIG. The power conversion device 1 may include the state quantity detection section anywhere as long as the state quantity can be detected at a position other than that shown in the figure. The power converter 1 converts noise generated in the power converter 1, motor 314, etc., loss generated in the power converter 1, motor 314, etc., temperature of each component included in the power converter 1, motor 314, etc. into state quantities. A state quantity detection unit may be provided at a position where these state quantities can be detected.

In addition, since both the basic pulse generating unit 410 and the waveform shape control signal outputting unit 420 operate based on the state quantities acquired from the state quantity detecting units 501 to 505, the control unit 400 controls the basic pulse generating unit 410. The functions of the waveform shape control signal output section 420 and the waveform shape control signal output section 420 may be combined into one configuration.

The motor 314 is a load connected to the power converter 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, and performs a compression operation. For example, when the compressor is a hermetic compressor, the load torque of the motor 314 that drives the compressor can often be regarded as a constant torque load. The motor 314 may have a Y-connection, a Δ-connection, or a specification in which the Y-connection and the Δ-connection can be switched for motor windings (not shown). Further, the load connected to the power conversion device 1, that is, the inverter 310 is not limited to the compressor driving motor 314, but may be a fan motor or the like. Further, the load connected to the power converter 1 is not limited to the motor 314, and may be a load other than the motor 314.

In the present embodiment, the power conversion device 1 can change the waveform shapes of the switching waveforms of the switching elements 311a to 311f of the inverter 310 using the waveform shape control signal output section 420 and the waveform shape changing section 340. 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.

FIG. 2 is a diagram showing an example of turn-on Joule loss, turn-on current, and turn-on voltage when the switching speed of switching elements 311a to 311f of inverter 310 is slowed down in power converter 1 according to the first embodiment. FIG. 3 is a diagram showing an example of turn-on Joule loss, turn-on current, and turn-on voltage when the switching speed of switching elements 311a to 311f of inverter 310 is increased in power converter 1 according to the first embodiment. In FIGS. 2 and 3, A indicates turn-on Joule loss, B indicates turn-on current, and C indicates turn-on voltage. In FIGS. 2 and 3, the horizontal axis indicates time. For example, the turn-on current is the current flowing through the switching element 311a, the turn-on voltage is the voltage applied across the switching element 311a, and the turn-on Joule loss is the product of the turn-on current and the turn-on voltage, but the measurement target is the switching element 311a. It is not limited to the element 311a, and other switching elements 311b to 311f may be used. Note that FIGS. 2 and 3 show the differences in characteristics depending on the switching speed of the switching elements 311a to 311f of the inverter 310, and the specific values of "slow" and "fast" in the switching speed are not particularly important. . As shown in FIGS. 2 and 3, by slowing down the switching speed, the noise represented by the peak value of the turn-on current of B becomes smaller, but the loss represented by the area of the turn-on joule loss of A becomes larger. Furthermore, as shown in Figures 2 and 3, by increasing the switching speed, the noise indicated by the peak value of the turn-on current of B increases, but the loss indicated by the area of the turn-on Joule loss of A decreases. . That is, in the switching elements 311a to 311f, there is a trade-off relationship between noise and loss generated.

In the power conversion device 1, the waveform shape changing unit 340 is configured by a digital gate driver. Alternatively, in the power conversion device 1, the switching elements 311a to 311f of the inverter 310 and the waveform shape changing section 340 are configured by a digital gate driver module. Thereby, the power conversion device 1 can change the switching speed of the switching elements 311a to 311f of the inverter 310 by changing the command value of the software without changing the hardware, and the switching elements 311a to 311f It is possible to control noise and loss generated in a desired state.

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

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

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

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

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

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

FIG. 8 is a first diagram showing the relationship between the gate current _IG output by the waveform shape changing unit 340 and the gate voltage _VG indicating the rising speed of the switching element 311a in the power conversion device 1 according to the first embodiment. be. FIG. 9 is a second diagram showing the relationship between the gate current _IG output by the waveform shape changing unit 340 and the gate voltage _VG indicating the rising speed of the switching element 311a in the power conversion device 1 according to the first embodiment. be. As shown in FIGS. 8 and 9, the waveform shape changing unit 340 can increase the rise of the gate voltage _VG , that is, increase the switching speed of the switching element 311a, as the output gate current _IG increases. can. Further, as shown in FIGS. 8 and 9, the waveform shape changing unit 340 slows down the rise of the gate voltage _VG , as the output gate current _IG becomes smaller, that is, the switching speed of the switching element 311a becomes slower. be able to. As a result, as shown in FIG. 5, when the power conversion device 1 wants to reduce the noise generated in the switching element 311a, the output gate current _IG is decreased to slow the switching speed, and the noise generated in the switching element 311a is reduced. When it is desired to reduce the loss, the output gate current _IG can be increased to increase the switching speed. Note that the waveforms of the gate current _IG and gate voltage _VG shown in FIGS. 8 and 9 are ideal examples, and in reality, as shown in FIGS. 2 and 3, the gate current _IG is constant. It will take time to reach the current value.

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

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

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

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

Note that, regarding the configuration of the waveform shape changing unit 340, the configuration of the waveform shape changing unit 340 shown in FIG. 7 is an example, and is not limited thereto. In this way, the waveform shape changing unit 340 uses digital control using a plurality of MOSs (Metal Oxide Semiconductors), compared to analog control in which the gate resistance is physically switched as described in Patent Document 1. The switching speed of the switching element 311a can be adjusted more finely. Furthermore, the waveform shape changing section 340 may use transistors other than MOS as internally used transistors.

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

Further, in the example of FIG. 7, the waveform shape changing unit 340 adjusts the switching speed of the switching element 311a by changing the gate current _IG as a drive signal output to the switching element 311a, and changes the switching waveform of the switching element 311a. Although the waveform shape was changed, the present invention is not limited to this. The waveform shape changing unit 340 sets the drive signal output to the switching element 311a to a gate voltage _VG , and by changing the gate voltage _VG , similarly adjusts the switching speed of the switching element 311a, and changes the switching waveform of the switching element 311a. The waveform shape of can be changed.

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

FIG. 12 is a flowchart showing the operation of changing the waveform shapes of the switching waveforms of the switching elements 311a to 311f in the power conversion device 1 according to the first embodiment. In the power conversion device 1, the basic pulse generation unit 410 generates basic pulses for driving the switching elements 311a to 311f of the inverter 310 based on the state quantities acquired from the state quantity detection units 501 to 505 (step S1 ). In this manner, in the control unit 400, the basic pulse generation unit 410 generates basic pulses based on the state quantities acquired from the state quantity detection units 501 to 505, and determines the timing for turning on and turning off the switching elements 311a to 311f. Decide on timing. The basic pulse generation section 410 outputs the generated basic pulse to the waveform shape control signal output section 420.

The waveform shape control signal output unit 420 determines the waveform 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 generation unit 410 and the state quantities obtained from the state quantity detection units 501 to 505. Set the waveform shape to change the shape. In this way, in the control section 400, the waveform shape control signal output section 420 turns on the switching elements 311a to 311f determined by the basic pulse generation section 410 based on the state quantities acquired from the state quantity detection sections 501 to 505. Set the waveform shape of the switching waveform at the turn-off timing and turn-off timing. The waveform shape control signal output section 420 outputs a control signal that can change the magnitude and output timing of the drive signal according to the set waveform shape to the waveform shape change section 340 (step S2).

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

Next, the hardware configuration of the control unit 400 included in the power conversion device 1 will be described. FIG. 13 is a diagram illustrating an example of a hardware configuration that implements the control unit 400 included in the power conversion device 1 according to the first embodiment. Control unit 400 is realized by processor 91 and memory 92.

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

As described above, according to the present embodiment, in the power conversion device 1, the waveform shape control signal output section 420 of the control section 400 performs the following according to the state quantities detected by the state quantity detection sections 501 to 505. The waveform shape changing section 340 of the inverter 310 outputs a control signal when changing the switching waveforms of the switching elements 311a to 311f. The waveform shape changing unit 340 of the inverter 310 changes the gate current I _G or gate voltage V _G output to the switching elements 311a to 311f based on the control signal output from the waveform shape control signal output unit 420. The waveform shape of the switching waveform of the switching elements 311a to 311f is changed. Thereby, the power conversion device 1 can change the switching speed of the switching elements 311a to 311f while suppressing an increase in circuit scale. The power conversion device 1 finely adjusts the gate current _IG or gate voltage _VG output to the switching elements 311a to 311f in one switching period, thereby increasing the switching element 311a, which could not be achieved with the method of Patent Document 1, etc. It is possible to realize a switching waveform shape of ~311f.

Embodiment 2.
In the first embodiment, a case has been described in which 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, a case will be described in which the waveform shape of the switching waveform of the switching element 136 of the converter 130 is changed in the power conversion device 1.

FIG. 14 is a diagram showing a configuration example of the power conversion device 1 according to the second embodiment. Power conversion device 1 is connected to commercial power source 110 and motor 314. The power conversion device 1 converts the first AC power of the power supply voltage Vs 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. The power conversion device 1 includes a state quantity detection section 501, a converter 130, a capacitor 210, a state quantity detection section 502, an inverter 310, a state quantity detection section 503, a state quantity detection section 504, and a state quantity detection section. 505 and a control unit 400. Note that the power conversion device 1 and the motor 314 constitute a motor drive device 2.

The power converter 1 of the second embodiment shown in FIG. 14 is different from the power converter 1 of the first embodiment shown in FIG. , the drive circuit 150 is removed from the converter 130 and a waveform shape changing section 140 is added. Moreover, the power converter 1 of the second embodiment shown in FIG. 14 is different from the power converter 1 of the first embodiment shown in FIG. is being changed. Specifically, basic pulse generation section 410 outputs a basic pulse for controlling the operation of switching element 136 of converter 130 to waveform shape control signal output section 420, and controls the operation of switching elements 311a to 311f of inverter 310. A basic pulse for control is output to the inverter 310. Further, the waveform shape control signal output section 420 outputs a control signal for controlling the operation of the waveform shape modification section 140 to the waveform shape modification section 140.

In the inverter 310, the drive circuit 350 generates drive signals for actually driving the switching elements 311a to 311f based on the basic pulses generated by the basic pulse generation unit 410 of the control unit 400.

In this embodiment, waveform shape control signal output section 420 changes the switching waveform of switching element 136 in waveform shape changing section 140 of converter 130 according to the state quantities detected by state quantity detection sections 501 to 505. The waveform shape of the switching waveform of the switching element 136 at that time is set, and a control signal indicating the set waveform shape is output. Specifically, when turning on and off switching element 136 based on the basic pulse generated by basic pulse generation unit 410 for controlling the operation of switching element 136 of converter 130, waveform shape control signal output unit 420 The waveform shape changing unit 140 of 130 controls the magnitude of the drive signal output to the switching element 136 and the timing of outputting the drive signal in order to actually drive the switching element 136. Waveform shape control signal output section 420 outputs a control signal for controlling the operation of waveform shape modification section 140 to waveform shape modification section 140 .

The waveform shape changing unit 140 can change the waveform shape of the switching waveform of the switching element 136. The waveform shape changing section 140 can output two or more waveform shapes as the waveform shape of the switching waveform of the switching element 136. Furthermore, the waveform shape changing section 140 is included in the converter 130, which is a power converter including a switching element 136, as shown in FIG. The configuration of waveform shape changing section 140 is similar to the configuration of waveform shape changing section 340 of Embodiment 1 shown in FIG. That is, the waveform shape changing section 140 and the switching element 136 are configured by one digital gate driver module. Further, like the waveform shape changing unit 340, the waveform shape changing unit 140 may adjust the gate voltage _VG output to the switching element 136 instead of the gate current _IG outputting to the switching element 136 as a drive signal. .

In this way, the waveform shape changing section 140 changes the waveform shape of the switching waveform of the switching element 136 between the turn-on period and the turn-off period of the switching element 136 based on the control signal output from the waveform shape control signal output section 420. At least one period can be divided into two or more periods, and the amplitude of the gate current _IG or gate voltage _VG applied to the switching element 136 can be changed to a different magnitude in each divided period. In addition, the waveform shape changing section 140 includes a plurality of transistors, and changes the number of transistors to be operated based on the control signal output from the waveform shape control signal output section 420, thereby increasing the gate current _IG or the gate voltage V. The amplitude of _G can be changed. As a result, power conversion device 1 performs the same operation as in the first embodiment to change the waveform shape of the switching waveform of switching element 136 of converter 130 using waveform shape control signal output section 420 and waveform shape modification section 140. Can be changed.

As described above, according to the present embodiment, in the power conversion device 1, the waveform shape control signal output section 420 of the control section 400 performs the following according to the state quantities detected by the state quantity detection sections 501 to 505. A control signal for changing the switching waveform of the switching element 136 in the waveform shape changing section 140 of the converter 130 is output. The waveform shape changing unit 140 of the converter 130 changes the gate current _IG or gate voltage _VG output to the switching element 136 based on the control signal output from the waveform shape control signal output unit 420. The waveform shape of the switching waveform of 136 is changed. The waveform shape changing section 140 can change the waveform shape of the switching waveform of the switching element 136 in the same way that the waveform shape changing section 340 of the first embodiment changes the waveform shape of the switching waveform of the switching element 311a. can. Thereby, the power conversion device 1 can change the switching speed of the switching element 136 while suppressing an increase in circuit scale. The power conversion device 1 finely adjusts the gate current _IG or gate voltage _VG output to the switching element 136 in one switching period, thereby achieving switching of the switching element 136 that could not be achieved with the method disclosed in Patent Document 1. A waveform shape of a waveform can be realized.

Note that in this embodiment, the configuration of converter 130, which is the target of changing the waveform shape of the switching element, is not limited to the example shown in FIG. 14. FIG. 15 is a first diagram showing a rectifying portion of converter 130 included in power conversion device 1 according to the second embodiment. FIG. 16 is a second diagram showing a rectifying portion of converter 130 included in power conversion device 1 according to the second embodiment. FIG. 17 is a third diagram showing a rectifying portion of converter 130 included in power conversion device 1 according to the second embodiment. 15 to 17, only the differences from FIG. 14 are shown, and the description of the waveform shape changing unit 140 is omitted. As shown in FIG. 15, in a configuration where the converter 130 includes a reactor 135, switching elements 136a to 136d, and freewheeling diodes 137a to 137d, the waveform shape changing section 140 changes the waveform shape of the switching waveform of the switching elements 136a to 136d. May be changed. Further, as shown in FIG. 16, in a configuration in which the converter 130 includes a reactor 135, rectifying elements 131 to 134, a switching element 136, a freewheeling diode 137, and rectifying elements 131a to 134a, the waveform shape changing unit 140 The waveform shape of the switching waveform of 136 may be changed. Further, as shown in FIG. 17, the connected commercial power source is a three-phase AC power source 110a, and the converter 130 includes reactors 135a to 135c, rectifying elements 131a to 131c, switching elements 136a to 136c, and In the configuration including the freewheeling diodes 137a to 137c, the waveform shape changing section 140 may change the waveform shape of the switching waveforms of the switching elements 136a to 136c.

Embodiment 3.
In the first embodiment, a case has been described in which 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, a case has been described in which the waveform shape of the switching waveform of the switching element 136 of the converter 130 is changed in the power conversion device 1. In the third embodiment, a case will be described in which, in power converter 1, the waveform shape of the switching waveform of switching elements 311a to 311f of inverter 310 is changed, and the waveform shape of the switching waveform of switching element 136 of converter 130 is changed.

FIG. 18 is a diagram showing a configuration example of the power conversion device 1 according to the third embodiment. Power conversion device 1 is connected to commercial power source 110 and motor 314. The power conversion device 1 converts the first AC power of the power supply voltage Vs 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. The power conversion device 1 includes a state quantity detection section 501, a converter 130, a capacitor 210, a state quantity detection section 502, an inverter 310, a state quantity detection section 503, a state quantity detection section 504, and a state quantity detection section. 505 and a control unit 400. Note that the power conversion device 1 and the motor 314 constitute a motor drive device 2.

A power conversion device 1 according to the third embodiment shown in FIG. 18 is different from the power conversion device 1 according to the first embodiment shown in FIG. It is something. Moreover, the power converter 1 of the third embodiment shown in FIG. 18 is different from the power converter 1 of the first embodiment shown in FIG. is being changed. Specifically, basic pulse generation section 410 outputs a basic pulse for controlling the operation of switching elements 311a to 311f of inverter 310 to waveform shape control signal output section 420, and controls the operation of switching element 136 of converter 130. A basic pulse for control is output to the waveform shape control signal output section 420. Further, the waveform shape control signal output section 420 outputs a control signal for controlling the operation of the waveform shape changing section 340 to the waveform shape changing section 340, and outputs a control signal for controlling the operation of the waveform shape changing section 140. It is output to the waveform shape changing section 140.

In this embodiment, the waveform shape control signal output section 420 performs the operation described in the first embodiment as well as the operation described in the second embodiment. Further, in this embodiment, waveform shape changing section 340 performs the same operation as described in Embodiment 1, and waveform shape changing section 140 performs the same operation as described in Embodiment 2. conduct. Thereby, by performing the same operation as in the first embodiment, the power converter 1 changes the waveforms of the switching waveforms of the switching elements 311a to 311f of the inverter 310 by the waveform shape control signal output section 420 and the waveform shape changing section 340. Can change shape. Furthermore, by performing the same operation as in the second embodiment, power converter 1 changes the waveform shape of the switching waveform of switching element 136 of converter 130 using waveform shape control signal output section 420 and waveform shape changing section 140. can do.

In the present embodiment, in the power conversion device 1, one of the waveform

shape changing units

140 and 340 changes the waveform shape of the switching waveform of the switching element at a certain timing, and the other changes the waveform shape of the switching waveform of the switching element. It is also possible to perform control that does not change the shape. In the present embodiment, the switching elements whose switching waveforms are changed by the waveform

shape changing units

140 and 340 of the power converter 1 are among the one or more power converters that perform power conversion in the power converter 1. One or more switching elements included in at least one power converter.

As described above, according to the present embodiment, in the power conversion device 1, the waveform shape control signal output section 420 of the control section 400 performs the following according to the state quantities detected by the state quantity detection sections 501 to 505. The waveform shape changing section 340 of the inverter 310 outputs a control signal when changing the switching waveform of the switching elements 311a to 311f, and the waveform shape changing section 140 of the converter 130 outputs a control signal when changing the switching waveform of the switching element 136. Output. The waveform shape changing unit 340 of the inverter 310 changes the gate current I _G or gate voltage V _G output to the switching elements 311a to 311f based on the control signal output from the waveform shape control signal output unit 420. The waveform shape of the switching waveform of the switching elements 311a to 311f is changed. In addition, the waveform shape changing section 140 of the converter 130 changes the gate current _IG or gate voltage _VG output to the switching element 136 based on the control signal output from the waveform shape control signal output section 420. The waveform shape of the switching waveform of the switching element 136 is changed. Thereby, power conversion device 1 can change the switching speed of switching elements 311a to 311f and switching element 136 while suppressing an increase in circuit scale. The power converter 1 finely adjusts the gate current _IG or the gate voltage _VG output to the switching elements 311a to 311f and the switching element 136 in one switching period, which is not possible with methods such as Patent Document 1. The waveform shapes of the switching waveforms of the switching elements 311a to 311f and the switching element 136 can be realized as follows.

Embodiment 4.
A case will be described in which an adaptive observer is applied as sensorless control of the motor 314 in the power converter device 1 of Embodiment 1 to Embodiment 3. Specifically, the power conversion device 1 of Embodiment 1 will be explained as an example.

FIG. 19 is a diagram illustrating a configuration example of power conversion device 1 according to Embodiment 4. A power converter 1 according to the fourth embodiment shown in FIG. 19 is obtained by adding a speed estimation device 101 to the power converter 1 according to the first embodiment shown in FIG. FIG. 20 is a diagram illustrating a configuration example of speed estimating device 101 included in power conversion device 1 according to Embodiment 4. The speed estimating device 101 estimates the rotational speed of the motor 314 using the voltage vector and current vector applied to the motor 314 using an adaptive observer method, and outputs it as an estimated angular speed ω^ _r .

The speed estimating device 101 includes a model deviation calculation unit 11 that calculates a model deviation ε based on a voltage vector, a current vector, and an estimated angular velocity ω^ _r , and a first and a first angular velocity estimation unit 21 that calculates the estimated angular velocity ω^ _r1 . The speed estimating device 101 also includes a second angular velocity estimator 22 that calculates a second estimated angular velocity ω^ _r2 as a high frequency component of the actual angular velocity based on a specific high frequency component included in the model deviation ε, and a first estimated angular velocity and an adder 23 that calculates the estimated angular velocity ω^ _r by adding the second estimated angular velocity ω^ _r2 to the angular velocity ω^ _r1 . The velocity estimating device 101 is characterized in that it includes a second angular velocity estimating section 22. The speed estimation device 101 feeds back the sum of the first estimated angular velocity ω^ _r1 and the second estimated angular velocity ω^ _r2 to the model deviation calculation unit 11 as the estimated angular velocity ω^ _r .

The model deviation calculation unit 11 includes a current estimator 12 that calculates and outputs an estimated magnetic flux vector and an estimated current vector based on the voltage vector, current vector, and estimated angular velocity ω^ _r of the motor 314, and a current estimator 12 that calculates and outputs an estimated magnetic flux vector and an estimated current vector, and a current vector that calculates a current vector from the estimated current vector. a subtracter 13 that calculates and outputs a current deviation vector; and a deviation calculator 14 that receives the current deviation vector, extracts the orthogonal component of the estimated magnetic flux vector as a scalar quantity, and outputs this value as a model deviation ε. , is provided. There are two methods to extract the orthogonal component of the estimated magnetic flux vector as a scalar quantity: one is to transform the coordinates of the current deviation vector onto two rotating axes, and the other is to calculate the size of the cross product of the current deviation vector and the estimated magnetic flux vector. is publicly known.

The current estimator 12 estimates the current and magnetic flux from the state equation of the motor 314. Here, it is assumed that the motor 314 is a general embedded magnet type synchronous AC motor, but even if the motor 314 is other than an embedded magnet type synchronous AC motor, the current estimator 12 can be used in the same manner as long as the state equation can be formulated. The current can be estimated using the following method. Examples of the motor 314 other than the embedded magnet type synchronous AC motor include a surface magnet type synchronous motor, an induction motor, and the like. Further, in this embodiment, a rotary motor will be described, but the same technique can also be applied to a direct drive motor. The reason is that a direct-acting motor can be interpreted as a rotary motor with an infinite rotor radius.

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

Embodiment 5.
In the power conversion device 1 of Embodiment 1 to Embodiment 3, a case will be described in which control is performed to suppress deterioration of smoothing capacitor 210 and to suppress enlargement of the device. Specifically, the power conversion device 1 of Embodiment 1 will be explained as an example.

FIG. 21 is a diagram showing a configuration example of the power conversion device 1 according to the fifth embodiment. The configuration of the power converter 1 according to the fifth embodiment shown in FIG. 21 is the same as that of the power converter 1 according to the first embodiment shown in FIG. Converter 130 is a rectifier that has a bridge circuit configured by rectifying elements 131 to 134, and rectifies first AC power of power supply voltage Vs supplied from commercial power supply 110 and outputs the rectifier.

In the present embodiment, control unit 400 outputs second AC power including pulsations corresponding to the pulsations of power flowing into capacitor 210 from converter 130, which is a rectifier, from inverter 310 to motor 314, which is a load. The operation of the inverter 310 is controlled accordingly. The pulsation corresponding to the pulsation of the power flowing into the capacitor 210 is a pulsation that varies depending on the frequency of the pulsation of the power flowing into the capacitor 210, for example. Thereby, the control unit 400 suppresses the current flowing through the capacitor 210. Note that the control unit 400 does not need to use all of the detection values obtained from each detection unit, and may perform control using some of the detection values.

The operation of the control unit 400 included in the power conversion device 1 will be described. In this embodiment, in the power converter 1, the load generated by the inverter 310 and the motor 314 can be considered as a constant load, and when viewed from the current output from the capacitor 210, the capacitor 210 has a constant current load. The following explanation will be given assuming that they are connected. Here, as shown in FIG. 21, the current flowing from converter 130 is defined as current I1, the current flowing through inverter 310 is defined as current I2, and the current flowing from capacitor 210 is defined as current I3. The current I2 is a combination of the current I1 and the current I3. Current I3 can be expressed as the difference between current I2 and current I1, ie, current I2-current I1. The current I3 has a positive direction in which the capacitor 210 is discharged, and a negative direction in which the capacitor 210 is charged. That is, current may flow into the capacitor 210, and current may flow out of the capacitor 210.

FIG. 22 shows, as a comparative example, an example of each of the currents I1 to I3 and the capacitor voltage Vdc of the capacitor 210 when the current output from the converter 130 is smoothed by the capacitor 210 and the current I2 flowing to the inverter 310 is kept constant. It is a diagram. From the top, current I1, current I2, current I3, and capacitor voltage Vdc of capacitor 210 generated in response to current I3 are shown. The vertical axes of currents I1, I2, and I3 indicate current values, and the vertical axis of capacitor voltage Vdc indicates voltage values. All horizontal axes indicate time t. Note that the carrier components of the inverter 310 are actually superimposed on the currents I2 and I3, but this is omitted here. The same shall apply thereafter. As shown in FIG. 22, in power conversion device 1, if current I1 flowing from converter 130 is sufficiently smoothed by capacitor 210, current I2 flowing to inverter 310 has a constant current value. However, a large current I3 flows through the capacitor 210, causing deterioration. Therefore, in the present embodiment, in power conversion device 1, control unit 400 controls current I2 flowing through inverter 310, that is, controls the operation of inverter 310, so as to reduce current I3 flowing through capacitor 210.

FIG. 23 shows currents I1 to I3 and capacitor voltage Vdc of capacitor 210 when control unit 400 of power converter 1 according to Embodiment 5 controls the operation of inverter 310 to reduce current I3 flowing to capacitor 210. It is a figure showing an example. From the top, current I1, current I2, current I3, and capacitor voltage Vdc of capacitor 210 generated in response to current I3 are shown. The vertical axes of currents I1, I2, and I3 indicate current values, and the vertical axis of capacitor voltage Vdc indicates voltage values. All horizontal axes indicate time t. Control unit 400 of power converter 1 controls the operation of inverter 310 so that current I2 as shown in FIG. It is possible to reduce the frequency component of the current flowing into the capacitor 210, thereby reducing the current I3 flowing into the capacitor 210. Specifically, the control unit 400 controls the operation of the inverter 310 so that a current I2 including a pulsating current whose main component is the frequency component of the current I1 flows through the inverter 310.

In this manner, in the power conversion device 1, the control unit 400 detects the pulsations corresponding to the state quantities detected by the state

quantity detection units

501, 502, and 503 from the inverter 310, which is a power converter, to the motor connected to the inverter 310. The operation of the inverter 310 is controlled so as to be superimposed on the drive pattern of the capacitor 314, and the charging/discharging current of the capacitor 210 is suppressed. Thereby, the power conversion device 1 can suppress deterioration of the smoothing capacitor 210.

Embodiment 6.
In the power conversion device 1 of Embodiment 1 to Embodiment 3, it is possible to suppress fluctuations in DC voltage even when changing the number of times of switching of a short-circuit part that short-circuits commercial power supply 110, which is an AC power supply, in accordance with load conditions. A case will be explained in which control is possible. Specifically, the power conversion device 1 of Embodiment 1 will be explained as an example.

FIG. 24 is a diagram illustrating a configuration example of a power conversion device 1 according to Embodiment 6. The power converter 1 according to the sixth embodiment shown in FIG. 24 differs from the power converter 1 according to the first embodiment shown in FIG. 30 has been added. The rectifier 170 includes a rectifier circuit including four rectifier elements 131 to 134, and a capacitor 210 that is connected between the output terminals of the rectifier circuit and smoothes the voltage of the full-wave rectified waveform output from the rectifier circuit. be done. The rectifier 170 rectifies and outputs the first AC power supplied from the commercial power source 110.

The shorting section 30 short-circuits the commercial power supply 110 via the reactor 135. The shorting section 30 includes a diode bridge 31 connected in parallel to the commercial power supply 110 via a reactor 135, and a shorting element 32 connected to both output ends of the diode bridge 31. When the shorting element 32 is a metal oxide semiconductor field effect transistor, the gate of the shorting element 32 is connected to the control section 400, and the shorting element 32 is turned on and off by a drive signal from the control section 400. When the shorting element 32 is turned on, the commercial power supply 110 is short-circuited via the reactor 135 and the diode bridge 31.

The control unit 400 controls the short circuit operation of the short circuit unit 30. The control unit 400 controls the on/off of the short circuit element 32 by current open loop control in the short circuit operation mode so that the short circuit unit 30 is short circuited at least twice or more during a half cycle of the power supply. The control unit 400 short-circuits the short circuit unit 30 at least twice during a half cycle of the commercial power supply 110 based on the load condition. Thereby, the power conversion device 1 can suppress fluctuations in the DC voltage even when changing the number of times the shorting section 30 that shorts the commercial power source 110 is switched in accordance with the load condition.

Embodiment 7.
FIG. 25 is a diagram illustrating a configuration example of refrigeration cycle application equipment 900 according to Embodiment 7. A refrigeration cycle application device 900 according to the seventh embodiment includes the power conversion device 1 described in the first embodiment. The refrigeration cycle application device 900 according to the seventh embodiment can also include the power conversion device 1 described in the second to sixth embodiments. The refrigeration cycle application device 900 according to the seventh embodiment can be applied to products including a refrigeration cycle, such as air conditioners, refrigerators, freezers, and heat pump water heaters. Note that in FIG. 25, components having the same functions as in the first embodiment are given the same reference numerals as in the first embodiment.

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

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

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

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

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

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

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

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

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

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

1 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 part, 31 Diode bridge, 32 Short circuit element, 101 Speed estimation device, 110, 110a Commercial power supply, 130 Converter, 131 to 134, 131a to 134a, 131b, 131c Rectifier element, 135, 135a to 135c Reactor, 136, 1 36a ~136d, 311a-311f switching element, 137, 137a-137d, 312a-312f free-wheeling diode, 138 diode, 140, 340 waveform shape changing unit, 150, 350 drive circuit, 170 rectifier, 210 capacitor, 310 inverter, 314 Motor , 315 Compressor, 400 Control unit, 410 Basic pulse generation unit, 420 Waveform shape control signal output unit, 501 to 505 State quantity detection unit, 900 Refrigeration cycle application equipment, 902 Four-way valve, 904 Compression mechanism, 906 Indoor heat exchanger , 908 Expansion valve, 910 Outdoor heat exchanger, 912 Refrigerant piping.

Claims

A power conversion device that performs power conversion,
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 section capable of changing the waveform shape of the switching waveform of the switching element;
a state quantity detection unit that detects a state quantity indicating an operating state of the power converter;
a waveform shape control signal output unit that outputs a control signal when the waveform shape changing unit changes the switching waveform of the switching element according to the state quantity;
A power conversion device comprising:
The waveform shape changing section changes the waveform shape of the switching waveform of the switching element to at least one of a turn-on period and a turn-off period of the switching element, based on the control signal output from the waveform shape control signal output section. one period is divided into two or more, and the amplitude of the gate current or gate voltage for the switching element can be changed to a different magnitude in each divided period,
The power conversion device according to claim 1.
The waveform shape changing section 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 section, and changes the amplitude of the gate current or the gate voltage. change,
The power conversion device according to claim 2.
The waveform shape changing unit is capable of changing a switching waveform to a different waveform shape for each switching period of the switching element during operation of the power conversion device.
The power conversion device according to any one of claims 1 to 3.
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.
The power conversion device according to any one of claims 1 to 4.
The waveform shape control signal output unit changes the waveform shape of the switching waveform of the switching element so that noise generated in the switching element satisfies specified requirements and reduces loss generated in the switching element. or changing the waveform shape of the switching waveform of the switching element so that the noise generated in the switching element is reduced while the loss generated in the switching element satisfies specified requirements;
The power conversion device according to any one of claims 1 to 5.
The power converter including the switching element further includes the waveform shape changing section,
the power converter is an inverter, a converter, or an inverter and a converter;
The power conversion device according to any one of claims 1 to 6.
a model deviation calculation unit that calculates a model deviation based on the voltage, current, and estimated angular velocity of the AC motor; and a first estimated angular velocity that calculates a first estimated angular velocity as a low frequency component including a DC component of the actual angular velocity based on the model deviation. an angular velocity estimation section; a second angular velocity estimation section that calculates a second estimated angular velocity as a high frequency component of the actual angular velocity based on a specific high frequency component included in the model deviation; an adder for adding estimated angular velocities;
The power conversion device according to any one of claims 1 to 7, comprising:
a rectifier that rectifies AC power supplied from a commercial power source;
a capacitor connected to the output end of the rectifier;
The power converter includes the waveform shape control signal output section, and the pulsation according to the state quantity detected by the state quantity detection section is superimposed on the drive pattern of the motor connected to the inverter from the inverter that is the power converter. a control unit that controls the operation of the inverter and suppresses the charging and discharging current of the capacitor;
The power conversion device according to any one of claims 1 to 7, comprising:
a rectifier that rectifies AC power supplied from a commercial power source;
a shorting section that shorts the commercial power supply via a reactor;
a control section that includes the waveform shape control signal output section and controls a short circuit operation of the short circuit section;
Equipped with
The control unit shorts the shorting portion at least twice during a half cycle of the commercial power supply based on a load condition.
The power conversion device according to any one of claims 1 to 7.
A motor drive device comprising the power conversion device according to any one of claims 1 to 10.
Refrigeration cycle applicable equipment comprising the power converter according to any one of claims 1 to 10.
The refrigerant used is any of R1234yf, R1234ze (E), R1243zf, HFO1123, HFO1132 (E), R1132a, CF3I, R290, R463A, R466A, R454A, R454B, R454C,
The refrigeration cycle application equipment according to claim 12.
setting a switching speed of a digital gate driver module included in the power conversion device according to flammability of the refrigerant;
The refrigeration cycle application equipment according to claim 13.