air conditioner

Abstract

This air conditioner (2) for performing air conditioning control comprises: one or more switching elements included in at least one power converter among one or more power converters that perform power conversion; a waveform-shape-changing unit that can change the waveform shape of the switching waveform of the switching element; operating state detection units (501-505) that detect the operating state of the air conditioner (2); and a waveform shape control signal output unit (420) that outputs a control signal when changing the switching waveform of the switching element in the waveform-shape-changing unit according to the operating state.

Description

Technical Field

[0001] The present disclosure relates to an air conditioner that performs air conditioning control.

Background Art

[0002] Conventionally, in power converters such as inverters and converters mounted on air conditioners, the switching speed of switching elements has been changed by switching and connecting gate resistors with different gate resistance values to the switching elements. For example, Patent Document 1 discloses a technique for switching gate resistors with different gate resistance values using a switch for a gate resistor connected to a switching element when changing the gate drive waveform of the switching element in an inverter control device including an inverter main circuit having a plurality of switching elements.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inverter control device described in Patent Document 1 is applied to an air conditioner, and by changing the switching speed of the switching element, it operates considering both noise and loss generated according to the operating state of the air conditioner. However, the inverter control device described in Patent Document 1 switches according to the gate resistance value of the gate resistor to change the switching speed of the switching element, but the number of gate resistance values is limited. Therefore, there is a problem that the inverter control device described in Patent Document 1 may not be able to set the switching speed of the switching element to an optimal condition depending on the operating state of the air conditioner, and may not be able to control the generation of noise and loss to a desired state.

[0005] This disclosure is made in view of the above and aims to provide an air conditioner capable of controlling the generation of noise and loss according to the operating conditions. [Means for solving the problem]

[0006] To solve the aforementioned problems and achieve the objectives, this disclosure provides an air conditioner that performs air conditioning control. The air conditioner includes 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 that can change the waveform shape of the switching waveform of the switching element without physically switching the gate resistance, an operating state detection unit that detects the operating state of the air conditioner, a basic pulse generation unit that determines the timing to turn on and turn off the switching element based on the operating state, and a waveform shape control signal output unit that sets the waveform shape of the switching waveform at the timing to turn on and turn off the switching element determined by the basic pulse generation unit based on the operating state, and outputs a control signal to the waveform shape changing unit that can change the magnitude of the drive signal and the output timing according to the set waveform shape. The waveform shape changing unit is a digital gate driver that changes the waveform shape of the switching waveform of the switching element based on a control signal obtained from the waveform shape control signal output unit. In addition to the operating status, information on the set temperature and operating mode of the air conditioner is also used. [Effects of the Invention]

[0007] The air conditioner described herein has the effect of being able to control the generation of noise and loss according to the operating conditions. [Brief explanation of the drawing]

[0008] [Figure 1] A diagram showing an example configuration of an air conditioner according to Embodiment 1. [Figure 2] This figure shows examples of turn-on joule loss, turn-on current, and turn-on voltage when the switching speed of the inverter's switching element is slowed down in the power conversion device of an air conditioner according to Embodiment 1. [Figure 3] This figure shows examples of turn-on joule loss, turn-on current, and turn-on voltage when the switching speed of the inverter's switching element is increased in the power conversion device of an air conditioner according to Embodiment 1. [Figure 4] This diagram shows an example of the relationship between noise and loss that occurs in typical switching elements. [Figure 5] Figure 1 shows the effect obtained by changing the switching speed of the switching element of the inverter in the power conversion device of the air conditioner according to Embodiment 1. [Figure 6] Figure 2 shows the effect obtained by changing the switching speed of the switching element of the inverter in the power conversion device of the air conditioner according to Embodiment 1. [Figure 7] This figure shows an example of the configuration of the waveform shape changing section of the power conversion device included in the air conditioner according to Embodiment 1. [Figure 8] Figure 1 shows the relationship between the gate current output by the waveform shape changing unit and the gate voltage indicating the rise time of the switching element in the power conversion device of the air conditioner according to Embodiment 1. [Figure 9] Figure 2 shows the relationship between the gate current output by the waveform shape changing unit and the gate voltage indicating the rise time of the switching element in the power conversion device of the air conditioner according to Embodiment 1. [Figure 10] Figure 3 shows the relationship between the gate current output by the waveform shape changing unit and the gate voltage indicating the rise time of the switching element in the power conversion device of the air conditioner according to Embodiment 1. [Figure 11] This figure shows 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 modification unit in the power conversion device of the air conditioner according to Embodiment 1. [Figure 12] A flowchart illustrating the operation of changing the waveform shape of the switching waveform of a switching element in the power conversion device of the air conditioner according to Embodiment 1. [Figure 13]This figure shows an example of a hardware configuration that realizes the control unit included in the power conversion device of the air conditioner according to Embodiment 1. [Figure 14] A diagram showing an example configuration of an air conditioner according to Embodiment 2. [Figure 15] Figure 1 shows the rectification portion of the converter included in the power conversion device of the air conditioner according to Embodiment 2. [Figure 16] Figure 2 shows the rectification portion of the converter included in the power conversion device of the air conditioner according to Embodiment 2. [Figure 17] Figure 3 shows the rectification portion of the converter included in the power conversion device of the air conditioner according to Embodiment 2. [Figure 18] A diagram showing an example configuration of an air conditioner according to Embodiment 3. [Figure 19] A diagram showing an example configuration of an air conditioner according to Embodiment 5. [Figure 20] This figure shows an example of the configuration of the speed estimation device included in the power conversion device of the air conditioner according to Embodiment 5. [Figure 21] A diagram showing an example configuration of an air conditioner according to Embodiment 6. [Figure 22] As a comparative example, the diagram shows examples of currents and capacitor voltages when the current output from the converter is smoothed with a capacitor, and the current flowing through the inverter is kept constant. [Figure 23] This figure shows examples of currents and capacitor voltages when the control unit of the power converter in the air conditioner according to Embodiment 6 controls the operation of the inverter to reduce the current flowing through the capacitor. [Figure 24] A diagram showing an example configuration of an air conditioner according to Embodiment 7. [Figure 25] A diagram showing an example configuration of an air conditioner according to Embodiment 8. [Modes for carrying out the invention]

[0009] An air conditioner according to an embodiment of this disclosure will be described in detail below with reference to the drawings.

[0010] Embodiment 1. Figure 1 shows an example of the configuration of an air conditioner 2 according to Embodiment 1. The air conditioner 2, which performs air conditioning control, comprises a power converter 1 and a motor 314. The power converter 1 is connected to a commercial power supply 110 and the motor 314. The power converter 1 converts the 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 it to the motor 314. In the example of Figure 1, the commercial power supply 110 is a single-phase AC power supply, but it may also be a three-phase AC power supply. The power converter 1 comprises an operating state detection unit 501, a converter 130, a capacitor 210, an operating state detection unit 502, an inverter 310, an operating state detection unit 503, an operating state detection unit 504, an operating state detection unit 505, and a control unit 400.

[0011] The operating state detection unit 501 detects the operating state of the air conditioner 2. The operating state detection unit 501 detects, for example, the voltage value of the AC power of the power supply voltage Vs supplied from the commercial power supply 110 to the converter 130, the current value of the AC power of the power supply voltage Vs supplied from the commercial power supply 110 to the converter 130, and so on.

[0012] Converter 130 is a power converter that converts AC power of power supply voltage Vs supplied from commercial power supply 110 into DC power. Converter 130 comprises rectifier elements 131-134, a reactor 135, a switching element 136, a freewheeling diode 137, a diode 138, and a drive circuit 150. Converter 130 has a bridge circuit composed of rectifier elements 131-134, rectifies the first AC power of power supply voltage Vs supplied from commercial power supply 110, and boosts the rectified DC power to output it. The drive circuit 150 generates a drive signal to actually drive the switching element 136 based on a basic pulse generated by the 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), a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a bipolar transistor, etc., but is not limited to these. Note that the configuration of the converter 130 is not limited to the example in Figure 1. The converter 130 may have one or more rectifier elements among the rectifier elements 131 to 134 replaced with switching elements. Also, in the power conversion device 1 of Embodiment 1 shown in Figure 1, the converter 130 may have only a rectification function and not a boost function. Furthermore, when the commercial power supply 110 is a three-phase AC power supply, the converter 130 will have a configuration that includes six rectifier elements.

[0013] Capacitor 210 is connected to the output terminal of converter 130 and smooths the DC power converted by converter 130. Capacitor 210 is, for example, an electrolytic capacitor or a film capacitor.

[0014] The operating state detection unit 502 detects the operating state of the air conditioner 2. The operating state detection unit 502 detects, for example, the voltage value of the DC power supplied from the capacitor 210 to the inverter 310.

[0015] The inverter 310 is a power converter connected across the capacitor 210. The inverter 310 includes 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, converting the power output from the converter 130 and capacitor 210 into a second AC power having a desired amplitude and phase, i.e., generating a second AC power, which is then output to the 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, including a full-bridge circuit, a single-phase bridge circuit, a half-bridge circuit, etc. In this embodiment, the inverter 310 also includes a waveform shape changing unit 340 that can change the waveform shape of the switching waveforms 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. In the example in Figure 1, the waveform shape changing unit 340 is configured to change the waveform shapes of the switching waveforms of the switching elements 311a to 311f, but it is possible to change the waveform shape of the switching waveform of at least one of the switching elements 311a to 311f. Alternatively, the inverter 310 may be configured to have a 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.

[0016] The operating state detection unit 503 detects the operating state of the air conditioner 2. The operating state detection unit 503 detects, for example, the voltage value of the second AC power supplied from the inverter 310 to the load motor 314, the current value of the second AC power supplied from the inverter 310 to the load motor 314, etc. The operating state detection unit 504 detects the operating state of the air conditioner 2. The operating state detection unit 504 detects, for example, the current value of the DC power supplied from the capacitor 210 to the inverter 310, etc. The operating state detection unit 505 detects the operating state of the air conditioner 2. The operating state detection unit 505 detects, for example, the current flowing through the switching elements 311b, 311d, and 311f, etc.

[0017] The control unit 400 acquires the operating status detected by the operating status detection units 501 to 505 from the operating status detection units 501 to 505, and controls the operation of the converter 130 and inverter 310 based on the acquired operating status. Specifically, it controls the on / off state of the switching element 136 of the converter 130 and the on / off state 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.

[0018] The basic pulse generation unit 410 generates basic pulses for controlling the operation of the switching elements 136 of the converter 130, with a duty cycle corresponding to the operating state detected by the operating state detection units 501 to 505. The basic pulse generation unit 410 also generates basic pulses for controlling the operation of the switching elements 311a to 311f of the inverter 310, with a duty cycle corresponding to the operating state detected by the operating state detection units 501 to 505. The basic pulse is, for example, a PWM (Pulse Width Modulation) signal with a duty cycle corresponding to the operating state detected by the operating state detection units 501 to 505. The basic pulse generation unit 410 outputs basic pulses for controlling the operation of the switching elements 136 of the converter 130 to the converter 130, and outputs basic pulses for controlling the operation of the switching elements 311a to 311f of the inverter 310 to the waveform shape control signal output unit 420.

[0019] The waveform shape control signal output unit 420 sets the waveform shape of the switching waveforms of the switching elements 311a to 311f when the waveform shape changing unit 340 of the inverter 310 changes the switching waveforms of the switching elements 311a to 311f, according to the operating state detected by the operating state detection units 501 to 505, and outputs a control signal indicating the set waveform shape. Specifically, 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 to control the operation of the switching elements 311a to 311f of the inverter 310, the waveform shape control signal output unit 420 controls the magnitude of the drive signal that the waveform shape changing unit 340 of the inverter 310 outputs to the switching elements 311a to 311f in order to actually drive the switching elements 311a to 311f, and the timing of outputting the drive signal. The waveform shape control signal output unit 420 outputs a control signal to the waveform shape changing unit 340 to control the operation of the waveform shape changing unit 340. The control unit 400 may be configured to have a waveform shape control signal output unit 420 for each waveform shape changing unit 340, i.e., six waveform shape changing units 340, when the inverter 310 has a waveform shape changing unit 340 for each switching element 311a to 311f, i.e., six waveform shape changing units 340.

[0020] In the example shown in Figure 1, the control unit 400 acquired the operating status detected by the operating status detection units 501 to 505 and controlled the operation of the converter 130 and inverter 310 based on the acquired operating status, but it is not limited to this. The control unit 400 can control the operation of the converter 130 and inverter 310 based on the operating status acquired from at least one of the operating status detection units 501 to 505. In the power converter 1, in the example described above, the operating status detection units 501 to 505 detected the voltage or current input to each component of the power converter 1, the voltage or current output from each component of the power converter 1, etc., as operating status, but the detection targets are not limited to these. Also, the installation locations of the operating status detection units 501 to 505 are not limited to the example shown in Figure 1. The power converter 1 does not need to have all of the operating status detection units 501 to 505 arranged as shown in Figure 1. The power converter 1 may have an operating state detection unit anywhere other than those shown in the diagram, as long as the operating state can be detected. The power converter 1 may have an operating state detection unit at a location where these operating states can be detected, and the operating state may be defined as noise generated by the power converter 1 and motor 314, losses generated by the power converter 1 and motor 314, and the temperature of each component of the power converter 1 and motor 314. Furthermore, the control unit 400 can use information such as the set temperature for the air conditioner 2 and the operating mode (heating, cooling, etc.) for the air conditioner 2, obtained from a remote controller (not shown) used by a user, etc., as the operating state of the air conditioner 2.

[0021] Furthermore, since the control unit 400 operates based on the operating state acquired from the operating state detection units 501 to 505, both the basic pulse generation unit 410 and the waveform shape control signal output unit 420 may be combined into a single configuration.

[0022] Motor 314 is a load connected to the power converter 1. Motor 314 is, for example, a compressor motor for driving a compressor. Motor 314 rotates in accordance with the amplitude and phase of the second AC power supplied from the inverter 310 and performs compression. For example, if the compressor is a sealed compressor used in the air conditioner 2, the load torque of the motor 314 driving the compressor can often be considered a constant torque load. Motor 314 may have a Y connection, a delta connection, or a specification that allows switching between Y and delta connections for the motor windings (not shown). Furthermore, the load connected to the power converter 1, i.e., the inverter 310, is not limited to the motor 314 for driving the compressor, but may also be a fan motor used in the air conditioner 2, etc. In other words, motor 314 can be a compressor motor, a fan motor, etc.

[0023] In this embodiment, the power converter 1 can change the waveform shape of the switching waveforms of the switching elements 311a to 311f of the inverter 310 using the waveform shape control signal output unit 420 and the waveform shape changing unit 340. Specifically, the power converter 1 can change the switching speed, delay time, etc., of the switching elements 311a to 311f of the inverter 310.

[0024] Figure 2 shows examples of turn-on Joule loss, turn-on current, and turn-on voltage when the switching speed of the switching elements 311a to 311f of the inverter 310 is slowed down in the power converter 1 of the air conditioner 2 according to Embodiment 1. Figure 3 shows examples of turn-on Joule loss, turn-on current, and turn-on voltage when the switching speed of the switching elements 311a to 311f of the inverter 310 is increased in the power converter 1 of the air conditioner 2 according to Embodiment 1. In Figures 2 and 3, A represents turn-on Joule loss, B represents turn-on current, and C represents turn-on voltage. In Figures 2 and 3, the horizontal axis represents time. For example, the turn-on current is the current flowing through the switching element 311a, the turn-on voltage is the voltage across the switching element 311a, and the turn-on Joule loss is the product of the turn-on current and the turn-on voltage. However, the measurement target is not limited to the switching element 311a, but may also be other switching elements 311b to 311f. Figures 2 and 3 show the differences in characteristics of the switching elements 311a to 311f of the inverter 310 depending on their switching speed, and the specific numerical values ​​of "slow" and "fast" switching speeds are not particularly important. As shown in Figures 2 and 3, slowing down the switching speed reduces the noise indicated by the peak value of the turn-on current B, but increases the loss indicated by the area of ​​the turn-on joule loss A. Also, as shown in Figures 2 and 3, increasing the switching speed increases the noise indicated by the peak value of the turn-on current B, but decreases the loss indicated by the area of ​​the turn-on joule loss A. In other words, there is a trade-off relationship between the noise and loss generated in the switching elements 311a to 311f.

[0025] In the power converter 1, the waveform shape changing unit 340 is configured by a digital gate driver. Alternatively, in the power converter 1, the switching elements 311a to 311f of the inverter 310 and the waveform shape changing unit 340 are configured by a digital gate driver module. As a result, the power converter 1 can change the switching speed of the switching elements 311a to 311f of the inverter 310 by changing the command values ​​in the software without changing the hardware, and can control the noise and loss generated in the switching elements 311a to 311f to a desired state.

[0026] Figure 4 shows an example of the relationship between noise and loss in a typical switching element. As mentioned above, there is a trade-off relationship between noise and loss in a switching element. Therefore, as shown in Figure 4, in a typical switching element, increasing the switching speed increases noise but decreases loss, and decreasing the switching speed decreases noise but increases loss.

[0027] Figure 5 is the 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 converter 1 of the air conditioner 2 according to Embodiment 1. Even when the power converter 1 is operating within the noise range specified for the product on which the power converter 1 is installed, i.e., the air conditioner 2, when the load state of the motor 314 changes from light load to heavy load, the curve showing the characteristics of noise and loss generated by the switching elements 311a to 311f moves upward to the right, as shown in Figure 5, resulting in an increase in noise. In other words, in the power converter 1, the heavier the load, the more noise increases. Therefore, the power converter 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.

[0028] When the load state of the motor 314 changes from light load to heavy load, the waveform shape control signal output unit 420 changes the waveform shape of the switching waveforms of the switching elements 311a to 311f so that the noise generated by the switching elements 311a to 311f meets the specified requirements. When the operating state is light load operation below the specified load, the waveform shape of the switching waveform of the switching element 311a is changed to suppress losses, and when the operating state is heavy load operation above the specified load, the waveform shape of the switching waveform of the switching element 311a is changed to suppress noise.

[0029] Figure 6 is a second figure showing the effect obtained by changing the switching speed of the switching elements 311a to 311f of the inverter 310 in the power converter 1 of the air conditioner 2 according to Embodiment 1. The power converter 1, specifically the waveform shape changing unit 340, divides, for example, the turn-on period or turn-off period into two or more periods during a single 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 a different magnitude in each divided period. As shown in Figure 6, the power converter 1 optimizes the switching waveform of the switching elements 311a to 311f, thereby obtaining noise and loss characteristics generated by the switching elements 311a to 311f that could not be obtained with general switching elements as shown in Figure 4.

[0030] Here, the configuration of the waveform shape changing unit 340 will be described. As an example, and for the sake of simplicity, the case in which the waveform shape changing unit 340 can change the waveform shape of the switching waveform of one switching element 311a will be described. Figure 7 is a diagram showing an example configuration of the waveform shape changing unit 340 of the power converter 1 provided in the air conditioner 2 according to Embodiment 1. Figure 7 is also a diagram showing an example configuration of one digital gate driver module composed of the waveform shape changing unit 340 and the switching element 311a. As shown in Figure 1, the waveform shape changing unit 340 is included in the inverter 310, which is a power converter including the switching element 311a. The waveform shape changing unit 340 includes n P-channel MOSFETs (PMOS - P-channel Metal Oxide Semiconductor) for turn-on, n PreDrivers for operating the n PMOSs, n N-channel MOSFETs (NMOS - N-channel Metal Oxide Semiconductor) for turn-off, and n PreDrivers for operating the n NMOSs.

[0031] The waveform shape changing unit 340 is connected to the control power supply Vdd and ground GND. The waveform shape changing unit 340 changes the number of PMOS or NMOS transistors to be operated based on the control signal from the waveform shape control signal output unit 420, thereby changing the gate current I, which is the drive signal output to the switching element 311a during each of the turn-on and turn-off periods. G The amplitude value can be changed in n ways, allowing the switching speed of the switching element 311a to be adjusted. The waveform shape changing unit 340 increases the number of PMOS or NMOS transistors being operated, and the gate current I output to the switching element 311a increases. G The absolute value of can be increased, and the switching speed of the switching element 311a can be increased. Also, the more PMOS and NMOS transistors the waveform shape changing unit 340 has inside, the finer the adjustment of the switching speed of the switching element 311a becomes possible, and the gate current I GThe faster the response to the increase or decrease, the finer the gate current I can be adjusted during one switching period. G Regarding the control signal from the waveform shape control signal output unit 420, it is only necessary to be able to change the number of PMOSs or NMOSs operated by the waveform shape changing unit 340, so it may be an analog signal or a digital signal. Also, in the example of FIG. 7, it shows that there are m control signals in parallel from the waveform shape control signal output unit 420 to the waveform shape changing unit 340, but this is just an example, and the number of control signals is not limited to m. The number of control signals may be a number capable of indicating the operation or non-operation of each PMOS and each NMOS, or it may be made one if it is an analog signal indicating voltage or the like.

[0032] FIG. 8 is a first diagram showing the relationship between the gate current I output by the waveform shape changing unit 340 in the power conversion device 1 included in the air conditioner 2 according to Embodiment 1 G and the gate voltage V indicating the rising speed of the switching element 311a. G FIG. 9 is a second diagram showing the relationship between the gate current I output by the waveform shape changing unit 340 in the power conversion device 1 included in the air conditioner 2 according to Embodiment 1 G and the gate voltage V indicating the rising speed of the switching element 311a. G As shown in FIGS. 8 and 9, the waveform shape changing unit 340 can increase the rising speed of the gate voltage V, that is, increase the switching speed of the switching element 311a, the larger the output gate current I is. Also, as shown in FIGS. 8 and 9, the waveform shape changing unit 340 can slow down the rising speed of the gate voltage V, that is, slow down the switching speed of the switching element 311a, the smaller the output gate current I is. Thereby, as shown in FIG. 5, when the power conversion device 1 wants to reduce the noise generated by the switching element 311a, it reduces the output gate current I to slow down the switching speed, and when it wants to reduce the loss generated by the switching element 311a, the output gate current I G The larger the output gate current I is, the faster the rising of the gate voltage V G That is, the switching speed of the switching element 311a can be increased. Also, as shown in FIGS. 8 and 9, the waveform shape changing unit 340 can slow down the rising of the gate voltage V, that is, slow down the switching speed of the switching element 311a, the smaller the output gate current I is. G The smaller the output gate current I is, the slower the rising of the gate voltage V G That is, the switching speed of the switching element 311a can be slowed down. Thus, the power conversion device 1 can reduce the output gate current I to slow down the switching speed when it wants to reduce the noise generated by the switching element 311a, and can reduce the output gate current I when it wants to reduce the loss generated by the switching element 311a. G is reduced to slow down the switching speed, and when it wants to reduce the loss generated by the switching element 311a, the output gate current IG The switching speed can be increased by increasing the gate current I shown in Figures 8 and 9. G and gate voltage V G The waveform shown is an ideal example; in reality, as shown in Figures 2 and 3, the gate current I G It will take time for the current to reach a constant value.

[0033] Figure 10 shows the gate current I output by the waveform shape changing unit 340 in the power converter 1 of the air conditioner 2 according to Embodiment 1. G and the gate voltage V, which indicates the rise time of the switching element 311a. G This is the third figure showing the relationship. As shown in Figure 10, the waveform shape changing unit 340 divides the turn-on period and controls the gate current I in each period. G The magnitude can be changed. That is, the waveform shape changing unit 340 changes the gate current I during one turn-on period. G The size can be finely adjusted. This allows the power converter 1 to maintain the same gate current I during the turn-on period. G Compared to the case where the output is as shown in Figure 6, it is possible to control the switching element 311a in a way that reduces the noise generated by the switching element 311a while also reducing the losses generated by the switching element 311a.

[0034] Figures 8 to 10 were used to explain the turn-on period of the switching element 311a as an example, but the same applies to the turn-off period of the switching element 311a. Figure 11 shows the basic pulse output by the basic pulse generation unit 410 and the gate current I output by the waveform shape changing unit 340 in the power conversion device 1 of the air conditioner 2 according to Embodiment 1. G This figure shows an example of the relationship. In Figure 11, |Ig2|>|Ig1|. The waveform shape changing unit 340 controls the gate current I during the turn-on period of the switching element 311a. G The period during which the output is generated is divided, and first the gate current Ig2 with a large amplitude is divided into parts. G After outputting, the gate current I of the next small amplitude current Ig1 GAlternatively, the gate current I of the small amplitude current Ig1 may be output first. G After outputting the next large-amplitude current Ig2, the gate current I G It may also output the following. Similarly, the waveform shape changing unit 340 controls the gate current I during the turn-off period of the switching element 311a. G The period during which the output is generated is divided, and first, the gate current I of the large amplitude current -Ig2 G After outputting the next small-amplitude current -Ig1 gate current I G Alternatively, you could output the gate current I of the small amplitude current -Ig1 first. G After outputting the next large-amplitude current -Ig2 gate current I G You may output this.

[0035] Thus, the waveform shape changing unit 340, based on the control signal output from the waveform shape control signal output unit 420, divides at least one of the turn-on period and turn-off period of the switching element 311a into two or more periods, and in each divided period, it controls the gate current I of the switching element 311a. G The amplitude can be changed to different magnitudes. Furthermore, the waveform shape changing unit 340 includes multiple transistors, and by changing the number of transistors operated based on the control signal output from the waveform shape control signal output unit 420, the gate current I can be changed. G The amplitude can be changed. This allows the air conditioner 2 to change the noise and loss generated by the switching element 311a according to the operating conditions.

[0036] Furthermore, the waveform shape changing unit 340 controls the gate current I for each switching cycle of the switching element 311a. GThe output pattern can be changed. The waveform shape changing unit 340 can change the switching waveform to a different waveform shape for each switching cycle of the switching element 311a while the power converter 1 is in operation. For example, the waveform shape changing unit 340 changes the waveform shape of the switching waveform of the switching element 311a while at least one of the motors 314 of the air conditioner 2, such as the compressor motor or fan motor, is rotating. 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 at the same frequency as the switching cycle of the switching element 311a. The waveform shape control signal output unit 420 may also change the waveform shape of the switching waveform of the switching element 311a at a frequency that is a positive integer multiple of the switching cycle of the switching element 311a.

[0037] The configuration of the waveform shape changing unit 340 shown in Figure 7 is merely an example and is not limited thereto. In this way, the waveform shape changing unit 340, through digital control using multiple MOS (Metal Oxide Semiconductors), can finely adjust the switching speed of the switching element 311a compared to the case of analog control that physically switches the gate resistance as described in Patent Document 1. Furthermore, the waveform shape changing unit 340 may use transistors other than MOS transistors for internal use.

[0038] Furthermore, the waveform shape changing unit 340, in the above example, changes the number of PMOS or NMOS to be operated according to the acquired control signal, and the gate current I corresponding to the number of PMOS or NMOS to be operated G The signal was output to the switching element 311a, but is not limited to this. The waveform shape changing unit 340 outputs a gate current I corresponding to the control signal. G The output pattern, or waveform shape, is stored in advance, and the gate current I is set according to the output pattern, or waveform shape, corresponding to the acquired control signal. G The output may also be the following. In addition, the waveform shape changing unit 340 outputs the control signals acquired in the past and the gate current I at the time of the control signals acquired in the past.G The output pattern, or waveform shape, is stored, and when the same control signal is acquired, the gate current I is set using the stored output pattern, or waveform shape. G The output may also be the same. The waveform shape changing unit 340 controls the gate current I according to the control signal. G By storing the output pattern, i.e., the waveform shape, the gate current I G This can reduce the processing load when outputting the output.

[0039] Furthermore, in the example shown in Figure 7, the waveform shape changing unit 340 outputs a gate current I as a drive signal to the switching element 311a. G By changing the gate voltage V, the switching speed of the switching element 311a is adjusted, and the waveform shape of the switching waveform of the switching element 311a is changed, but this is not limited to this. G Let the gate voltage V G By changing this, the switching speed of the switching element 311a can be adjusted, and the waveform shape of the switching waveform of the switching element 311a can be changed.

[0040] Thus, the waveform shape changing unit 340, based on the control signal output from the waveform shape control signal output unit 420, divides at least one of the turn-on period and turn-off period of the switching element 311a into two or more periods, and applies a gate voltage V to the switching element 311a in each of the divided periods. G The amplitude can be changed to different magnitudes. Furthermore, the waveform shape changing unit 340 includes multiple transistors, and by changing the number of transistors operated based on the control signal output from the waveform shape control signal output unit 420, the gate voltage V can be changed. G The amplitude can be changed. This allows the air conditioner 2 to change the noise and loss generated by the switching element 311a according to the operating conditions.

[0041] Figure 12 is a flowchart illustrating the operation of changing the waveform shape of the switching waveforms of the switching elements 311a to 311f in the power converter 1 of the air conditioner 2 according to Embodiment 1. In the power converter 1, the basic pulse generation unit 410 generates basic pulses to drive the switching elements 311a to 311f of the inverter 310 based on the operating state acquired from the operating state detection units 501 to 505 (step S1). In this way, the control unit 400 generates basic pulses based on the operating state acquired from the operating state detection units 501 to 505 and determines the timing for turning on and turning off the switching elements 311a to 311f. The basic pulse generation unit 410 outputs the generated basic pulses to the waveform shape control signal output unit 420.

[0042] The waveform shape control signal output unit 420 sets the waveform shape to change the waveform shape of the switching waveforms of the switching elements 311a to 311f of the inverter 310, based on the basic pulses obtained from the basic pulse generation unit 410 and the operating status obtained from the operating status detection units 501 to 505. In this way, the control unit 400 sets the waveform shape of the switching waveforms at the timing for turning on and turning off the switching elements 311a to 311f determined by the basic pulse generation unit 410, based on the operating status obtained from the operating status detection units 501 to 505. The waveform shape control signal output unit 420 outputs a control signal to the waveform shape changing unit 340 that can change the magnitude and output timing of the drive signal according to the set waveform shape (step S2).

[0043] The waveform shape changing unit 340 outputs gate current I to the switching elements 311a to 311f of the inverter 310. G The waveform shape, that is, the waveform shape of the switching waveforms of the switching elements 311a to 311f, is changed based on the control signal obtained from the waveform shape control signal output unit 420 (step S3). The waveform shape changing unit 340 then checks the gate current I after the waveform shape change. GThis is output to the switching elements 311a to 311f of the inverter 310.

[0044] Next, the hardware configuration of the control unit 400 of the power converter 1 will be described. Figure 13 is a diagram showing an example of the hardware configuration for realizing the control unit 400 of the power converter 1 of the air conditioner 2 according to Embodiment 1. The control unit 400 is realized by a processor 91 and a memory 92.

[0045] The processor 91 is a CPU (Central Processing Unit, also known as a microprocessor, microcomputer, processor, or DSP (Digital Signal Processor)) or a system LSI (Large Scale Integration). Examples of memory 92 include non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory). However, memory 92 is not limited to these and may also be a magnetic disk, optical disk, compact disk, minidisc, or DVD (Digital Versatile Disc).

[0046] As described above, according to this embodiment, in the power converter 1 of the air conditioner 2, 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 in the waveform shape changing unit 340 of the inverter 310, according to the operating state detected by the operating state detection units 501 to 505. The waveform shape changing unit 340 of the inverter 310 outputs a gate current I 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 GBy changing this, the waveform shape of the switching waveform of switching elements 311a to 311f is changed. This allows the air conditioner 2 to control the generation of noise and loss according to the operating conditions. In addition, the air conditioner 2 can change the switching speed of switching elements 311a to 311f while suppressing an increase in circuit size. The air conditioner 2 outputs gate current I to switching elements 311a to 311f during one switching period. G or gate voltage V G By finely adjusting these parameters, it is possible to achieve waveform shapes for the switching waveforms of switching elements 311a to 311f that could not be realized with methods such as those described in Patent Document 1.

[0047] Embodiment 2. Embodiment 1 described a case in which the waveform shape of the switching waveforms of the switching elements 311a to 311f of the inverter 310 in the power conversion device 1 of the air conditioner 2 is changed. Embodiment 2 describes a case in which the waveform shape of the switching element 136 of the converter 130 in the power conversion device 1 of the air conditioner 2 is changed.

[0048] Figure 14 shows an example of the configuration of an air conditioner 2 according to Embodiment 2. The air conditioner 2 comprises a power converter 1 and a motor 314. The power converter 1 is connected to a commercial power supply 110 and the motor 314. The power converter 1 converts a first AC power of power supply voltage Vs supplied from the commercial power supply 110 into a second AC power having a desired amplitude and phase, and supplies it to the motor 314. The power converter 1 comprises an operating state detection unit 501, a converter 130, a capacitor 210, an operating state detection unit 502, an inverter 310, an operating state detection unit 503, an operating state detection unit 504, an operating state detection unit 505, and a control unit 400.

[0049] The power converter 1 of Embodiment 2 shown in Figure 14 is modified from the power converter 1 of Embodiment 1 shown in Figure 1 by removing the waveform shape changing unit 340 from the inverter 310 and adding a drive circuit 350, and by removing the drive circuit 150 from the converter 130 and adding a waveform shape changing unit 140. Furthermore, the power converter 1 of Embodiment 2 shown in Figure 14 has modified output destinations for the basic pulse generation unit 410 and the waveform shape control signal output unit 420 compared to the power converter 1 of Embodiment 1 shown in Figure 1. Specifically, the basic pulse generation unit 410 outputs basic pulses to the waveform shape control signal output unit 420 to control the operation of the switching elements 136 of the converter 130, and outputs basic pulses to the inverter 310 to control the operation of the switching elements 311a to 311f of the inverter 310. In addition, the waveform shape control signal output unit 420 outputs a control signal to the waveform shape changing unit 140 to control the operation of the waveform shape changing unit 140.

[0050] In the inverter 310, the drive circuit 350 generates a drive signal to actually drive the switching elements 311a to 311f based on the basic pulse generated by the basic pulse generation unit 410 of the control unit 400.

[0051] In this embodiment, the waveform shape control signal output unit 420 sets the waveform shape of the switching waveform of the switching element 136 when the waveform shape changing unit 140 of the converter 130 changes the switching waveform of the switching element 136, according to the operating state detected by the operating state detection units 501 to 505, and outputs a control signal indicating the set waveform shape. Specifically, when the switching element 136 is turned on and off based on the basic pulses generated by the basic pulse generation unit 410 for controlling the operation of the switching element 136 of the converter 130, the waveform shape control signal output unit 420 controls the magnitude of the drive signal that the waveform shape changing unit 140 of the converter 130 outputs to the switching element 136 in order to actually drive the switching element 136, and the timing of outputting the drive signal. The waveform shape control signal output unit 420 outputs a control signal to the waveform shape changing unit 140 for controlling the operation of the waveform shape changing unit 140.

[0052] 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. Furthermore, as shown in Figure 14, the waveform shape changing unit 140 is included in the converter 130, which is a power converter that includes the switching element 136. The configuration of the waveform shape changing unit 140 is the same as the configuration of the waveform shape changing unit 340 in Embodiment 1 shown in Figure 7. That is, the waveform shape changing unit 140 and the switching element 136 are configured by a single digital gate driver module. Also, similar to the waveform shape changing unit 340, the waveform shape changing unit 140 outputs a gate current I to the switching element 136 as a drive signal. G Instead, the gate voltage V output to the switching element 136 G You may adjust it.

[0053] Thus, the waveform shape changing unit 140, based on the control signal output from the waveform shape control signal output unit 420, divides at least one of the turn-on period and turn-off period of the switching element 136 into two or more periods, and in each divided period, it controls the gate current I of the switching element 136. G or gate voltage V G The amplitude can be changed to different magnitudes. Furthermore, the waveform shape changing unit 140 includes multiple transistors, and by changing the number of transistors operated based on the control signal output from the waveform shape control signal output unit 420, the gate current I can be changed. G or gate voltage V G The amplitude can be changed. As a result, the power converter 1 can change the waveform shape of the switching waveform of the switching element 136 of the converter 130 by performing the same operation as in Embodiment 1, using the waveform shape control signal output unit 420 and the waveform shape changing unit 140. In addition, the air conditioner 2 can change the noise and loss generated by the switching element 136 according to the operating conditions.

[0054] As described above, according to this embodiment, in the power converter 1 of the air conditioner 2, 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 in the waveform shape changing unit 140 of the converter 130, according to the operating state detected by the operating state detection units 501 to 505. The waveform shape changing unit 140 of the converter 130 outputs a gate current I 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 By changing the waveform shape of the switching waveform of the switching element 136, the waveform shape change unit 140 can change the waveform shape of the switching waveform of the switching element 136, just as the waveform shape change unit 340 in Embodiment 1 changes the waveform shape of the switching waveform of the switching element 311a. As a result, the air conditioner 2 can control the generation of noise and loss according to the operating state. In addition, the air conditioner 2 can change the switching speed of the switching element 136 while suppressing an increase in circuit size. The air conditioner 2 outputs a gate current I to the switching element 136 during one switching period. G or gate voltage V G By finely adjusting the settings, it is possible to achieve a waveform shape for the switching waveform of the switching element 136 that could not be achieved with methods such as those described in Patent Document 1.

[0055] In this embodiment, the configuration of the converter 130 whose waveform shape of the switching elements is to be changed is not limited to the example in Figure 14. Figure 15 is a first diagram showing the rectification portion of the converter 130 provided in the power converter 1 of the air conditioner 2 according to Embodiment 2. Figure 16 is a second diagram showing the rectification portion of the converter 130 provided in the power converter 1 of the air conditioner 2 according to Embodiment 2. Figure 17 is a third diagram showing the rectification portion of the converter 130 provided in the power converter 1 of the air conditioner 2 according to Embodiment 2. In Figures 15 to 17, only the differences from Figure 14 are shown, and the description of the waveform shape changing unit 140 is omitted. As shown in Figure 15, in a configuration in which the converter 130 includes a reactor 135, switching elements 136a to 136d, and freewheeling diodes 137a to 137d, the waveform shape changing unit 140 may change the waveform shape of the switching waveforms of the switching elements 136a to 136d. Furthermore, as shown in Figure 16, in a configuration where the converter 130 comprises a reactor 135, rectifier elements 131-134, switching element 136, freewheeling diode 137, and rectifier elements 131a-134a, the waveform shape changing unit 140 may change the waveform shape of the switching waveform of the switching element 136. Also, as shown in Figure 17, in a case where the connected commercial power supply is a three-phase AC commercial power supply 110a, and the converter 130 comprises reactors 135a-135c, rectifier elements 131a-131c, switching elements 136a-136c, and freewheeling diodes 137a-137c, the waveform shape changing unit 140 may change the waveform shape of the switching waveform of the switching elements 136a-136c.

[0056] Embodiment 3. Embodiment 1 describes a case in which the waveform shape of the switching elements 311a to 311f of the inverter 310 is changed in the power conversion device 1 of the air conditioner 2. Embodiment 2 describes a case in which the waveform shape of the switching element 136 of the converter 130 is changed in the power conversion device 1 of the air conditioner 2. Embodiment 3 describes a case in which the waveform shape of the switching elements 311a to 311f of the inverter 310 is changed and the waveform shape of the switching element 136 of the converter 130 is changed in the power conversion device 1 of the air conditioner 2.

[0057] Figure 18 shows an example of the configuration of an air conditioner 2 according to Embodiment 3. The air conditioner 2 comprises a power converter 1 and a motor 314. The power converter 1 is connected to a commercial power supply 110 and the motor 314. The power converter 1 converts a first AC power of power supply voltage Vs supplied from the commercial power supply 110 into a second AC power having a desired amplitude and phase, and supplies it to the motor 314. The power converter 1 comprises an operating state detection unit 501, a converter 130, a capacitor 210, an operating state detection unit 502, an inverter 310, an operating state detection unit 503, an operating state detection unit 504, an operating state detection unit 505, and a control unit 400.

[0058] The power converter 1 of Embodiment 3 shown in Figure 18 is modified from the power converter 1 of Embodiment 1 shown in Figure 1 by removing the drive circuit 150 from the converter 130 and adding a waveform shape changing unit 140. Furthermore, the power converter 1 of Embodiment 3 shown in Figure 18 has modified output destinations for the basic pulse generation unit 410 and the waveform shape control signal output unit 420 compared to the power converter 1 of Embodiment 1 shown in Figure 1. Specifically, the basic pulse generation unit 410 outputs basic pulses to the waveform shape control signal output unit 420 to control the operation of the switching elements 311a to 311f of the inverter 310, and outputs basic pulses to the waveform shape control signal output unit 420 to control the operation of the switching element 136 of the converter 130. In addition, the waveform shape control signal output unit 420 outputs a control signal to the waveform shape changing unit 340 to control the operation of the waveform shape changing unit 340, and outputs a control signal to the waveform shape changing unit 140 to control the operation of the waveform shape changing unit 140.

[0059] In this embodiment, the waveform shape control signal output unit 420 performs the operation described in Embodiment 1 as well as the operation described in Embodiment 2. In this embodiment, the waveform shape changing unit 340 performs the same operation as described in Embodiment 1, and the waveform shape changing unit 140 performs the same operation as described in Embodiment 2. As a result, the power converter 1 can change the waveform shape of the switching waveforms of the switching elements 311a to 311f of the inverter 310 by performing the same operation as in Embodiment 1, using the waveform shape control signal output unit 420 and the waveform shape changing unit 340. In addition, the power converter 1 can change the waveform shape of the switching waveform of the switching element 136 of the converter 130 by performing the same operation as in Embodiment 2, using the waveform shape control signal output unit 420 and the waveform shape changing unit 140.

[0060] In this embodiment, the power converter 1 can also perform control such that, at a certain timing, one of the waveform shape changing units 140 and 340 changes the waveform shape of the switching element's switching waveform, while the other does not change the waveform shape of the switching element's switching waveform. In this embodiment, the switching elements whose switching waveforms are changed by the waveform shape changing units 140 and 340 of the power converter 1 are one or more switching elements included in at least one of the power converters among the one or more power converters that perform power conversion in the power converter 1.

[0061] As described above, according to this embodiment, in the power conversion device 1 of the air conditioner 2, 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 at the waveform shape changing unit 340 of the inverter 310, according to the operating state detected by the operating state detection units 501 to 505, and outputs a control signal for changing the switching waveform of the switching element 136 at the waveform shape changing unit 140 of the converter 130. The waveform shape changing unit 340 of the inverter 310 outputs a gate current I 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 By changing this, the waveform shape of the switching waveforms of the switching elements 311a to 311f is changed. In addition, the waveform shape changing unit 140 of the converter 130 outputs the gate current I 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 GBy changing this, the waveform shape of the switching waveform of the switching element 136 is changed. This allows the air conditioner 2 to control the generation of noise and loss according to the operating conditions. In addition, the air conditioner 2 can change the switching speed of the switching elements 311a to 311f and the switching element 136 while suppressing an increase in circuit size. The air conditioner 2 outputs gate current I to the switching elements 311a to 311f and the switching element 136 during one switching period. G or gate voltage V G By finely adjusting these parameters, it is possible to achieve waveform shapes for the switching waveforms of switching elements 311a to 311f and switching element 136, which could not be achieved with methods such as those described in Patent Document 1.

[0062] Embodiment 4. In Embodiments 1 to 3, the power converter 1 of the air conditioner 2 changed the waveform shape of the switching waveforms of the switching elements 311a to 311f and the switching element 136 according to the load condition of the motor 314 mounted on the air conditioner 2. Embodiment 4 describes a method for determining the load condition of the power converter 1. The following explanation will specifically use the power converter 1 of Embodiment 1 as an example.

[0063] The operating state of the air conditioner 2 varies greatly depending on the operating conditions. For example, in a room that the air conditioner 2 controls, if the temperature difference between the user's set temperature (i.e., the user's desired temperature) and the current room temperature is large, the load on the power converter 1 installed in the air conditioner 2 increases. On the other hand, if the temperature difference between the user's desired temperature and the current room temperature is small, the load on the power converter 1 installed in the air conditioner 2 decreases.

[0064] The power converter 1 can detect the current flowing through each part and the voltage applied to each part based on the load state, for example, the detected values ​​of the operating state detection units 501 to 505. The power converter 1 can also detect the temperature based on the load state, for example, the detected value of a temperature sensor (not shown) on the indoor unit of the air conditioner 2, the detected value of a temperature sensor (not shown) on the outdoor unit. The power converter 1 may also be equipped with a temperature sensor around the circuit board of the inverter 310 to detect the temperature around the circuit board of the inverter 310, or a temperature sensor around the motor 314 to detect the temperature around the motor 314. Furthermore, the power converter 1 can directly or indirectly detect the operating speed, for example, the operating speed of the motor 314, such as the compressor motor or fan motor, based on the command value generated during the control process of the control unit 400, or an estimated value estimated from the operating frequency during the control process of the control unit 400. Thus, the load state is obtained by at least one of the following: the detected values ​​from the operating state detection units 501 to 505 that detect the operating state of the inverter 310, motor 314, etc., the command values ​​generated during the control process of the control unit 400, and the estimated values ​​estimated during the control process of the control unit 400.

[0065] Furthermore, the power converter 1 can also determine the operating status of the air conditioner 2 according to the air conditioning conditions of the air conditioner 2. Examples of air conditioning conditions for the air conditioner 2 include intermediate cooling conditions, rated cooling conditions, intermediate heating conditions, and rated heating conditions.

[0066] Immediately after the air conditioner 2 enters cooling mode via user input, the indoor temperature and the set temperature are far apart. The motor 314 used in the compressor and other components operates at high speed, resulting in a high workload. This state represents the air conditioning conditions known as the cooling rated conditions, and power consumption is high, i.e., it is under heavy load. Once the air conditioner 2 has fully operated under the cooling rated conditions, the indoor temperature and the set temperature are close together. The motor 314 used in the compressor and other components switches to low speed rotation, resulting in a low workload. This state represents the air conditioning conditions known as the cooling intermediate conditions, and power consumption is low, i.e., it is under low load.

[0067] Furthermore, immediately after the air conditioner 2 enters heating mode via user operation, the indoor temperature and the set temperature are far apart. The motor 314 used in the compressor and other components operates at high speed, resulting in a high workload. This state represents the air conditioning conditions known as heating rated conditions, and power consumption is high, i.e., it is under heavy load. Once the air conditioner 2 has fully operated under heating rated conditions, the indoor temperature and the set temperature are close together. The motor 314 used in the compressor and other components switches to low-speed rotation, resulting in a low workload. This state represents the air conditioning conditions known as heating intermediate conditions, and power consumption is low, i.e., it is under low load. In addition, there is an air conditioning condition for the air conditioner 2 called heating low-temperature conditions, which is an operating mode in an environment where the outside temperature is lower than under heating rated conditions. Under heating low-temperature conditions, the load is greater than under heating rated conditions, and power consumption is even higher.

[0068] Thus, the waveform shape control signal output unit 420 operates under light load conditions when the air conditioner 2 is operating under intermediate cooling conditions or intermediate heating conditions, and under heavy load conditions when the air conditioner 2 is operating under rated cooling conditions, rated heating conditions, or other air temperature conditions.

[0069] Furthermore, the waveform shape control signal output unit 420 may operate under light load conditions if the difference between the outside temperature and the set temperature of the air conditioner 2 is less than a specified threshold, and under heavy load conditions if the difference between the outside temperature and the set temperature of the air conditioner 2 is equal to or greater than a specified threshold.

[0070] Furthermore, the waveform shape control signal output unit 420 may operate under light load conditions if at least one of the load current and load power output from the inverter 310, which is a power converter, is below a specified threshold, and may operate under heavy load conditions if at least one of the load current and load power output from the inverter 310 is equal to or greater than a specified threshold.

[0071] Furthermore, the waveform shape control signal output unit 420 operates under light load conditions if at least one of the input current and input power input to the power converter, inverter 310 or converter 130, is below a specified threshold, and operates under heavy load conditions if at least one of the input current and input power input to the power converter, inverter 310 or converter 130, is equal to or greater than a specified threshold.

[0072] Embodiment 5. In the power conversion device 1 of Embodiments 1 to 4, the case in which an adaptive observer is applied as sensorless control of the motor 314 will be described. Specifically, the power conversion device 1 of Embodiment 1 will be used as an example.

[0073] Figure 19 shows an example of the configuration of an air conditioner 2 according to Embodiment 5. The air conditioner 2 comprises a power converter 1 and a motor 314. The power converter 1 of Embodiment 5 shown in Figure 19 is the same as the power converter 1 of Embodiment 1 shown in Figure 1, but with the addition of a speed estimation device 101. Note that in Figure 19, the converter 130, inverter 310, and control unit 400 within the power converter 1 are described in a simplified manner. Figure 20 shows an example of the configuration of the speed estimation device 101 included in the power converter 1 of the air conditioner 2 according to Embodiment 5. The speed estimation device 101 estimates the rotational speed of the motor 314 using the voltage vector and current vector applied to the motor 314 by an adaptive observer method, and estimates the angular velocity ω^ r Output as follows.

[0074] The velocity estimation device 101 uses a voltage vector, a current vector, and an estimated angular velocity ω^ r A model deviation calculation unit 11 calculates the model deviation ε based on the model deviation ε, and a first estimated angular velocity ω^ is calculated as a low-frequency component including the DC component of the actual angular velocity based on the model deviation ε. r1 The velocity estimation device 101 also includes a first angular velocity estimation unit 21 that calculates the second estimated angular velocity ω^ based on a specific high-frequency component included in the model deviation ε. r2 A second angular velocity estimation unit 22 calculates the first estimated angular velocity ω^ r1 The second estimated angular velocity ω^ r2 By adding this, the estimated angular velocity ω^ r The velocity estimation device 101 is characterized by having 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 these values ​​is the estimated angular velocity ω^ r This is then fed back to the model deviation calculation unit 11.

[0075] The model deviation calculation unit 11 calculates the voltage vector and current vector of the motor 314 and the estimated angular velocity ω^ rThe system comprises a current estimator 12 that calculates and outputs an estimated magnetic flux vector and an estimated current vector based on the above, a subtractor 13 that subtracts the current vector from the estimated current vector and calculates and outputs a current deviation vector, and a deviation calculator 14 that takes the current deviation vector as input, extracts the orthogonal component of the estimated magnetic flux vector as a scalar quantity, and outputs this value as the model deviation ε. Known methods for extracting the orthogonal component of the estimated magnetic flux vector as a scalar quantity include a method of coordinate transformation of the current deviation vector on two rotation axes and a method of calculating the magnitude of the cross product of the current deviation vector and the estimated magnetic flux vector.

[0076] The current estimator 12 estimates the current and magnetic flux from the state equation of the motor 314. Here, we assume that the motor 314 is a general embedded magnet type synchronous AC motor, but even if the motor 314 is not an embedded magnet type synchronous AC motor, the current estimator 12 can estimate the current in the same way as long as the state equation can be formulated. Examples of motors 314 other than embedded magnet type synchronous AC motors include surface magnet type synchronous motors and induction motors. Furthermore, although this embodiment describes rotary motors, the same technology can be applied to linear motors. This is because a linear motor can be interpreted as a rotary motor with an infinite rotor radius.

[0077] Thus, the air conditioner 2 can apply an adaptive observer as sensorless control of the motor 314.

[0078] Embodiment 6. In the power conversion device 1 of Embodiments 1 to 3, a case will be described in which control is performed in a way that suppresses the degradation of the smoothing capacitor 210 while suppressing the increase in the size of the device. Specifically, the power conversion device 1 of Embodiment 1 will be used as an example.

[0079] Figure 21 is a diagram showing an example configuration of an air conditioner 2 according to Embodiment 6. The air conditioner 2 comprises a power converter 1 and a motor 314. The configuration of the power converter 1 of Embodiment 6 shown in Figure 21 is the same as that of the power converter 1 of Embodiment 1 shown in Figure 1. The converter 130 has a bridge circuit composed of rectifier elements 131 to 134 and is a rectifier unit that rectifies and outputs the first AC power of the power supply voltage Vs supplied from the commercial power supply 110.

[0080] In this embodiment, the control unit 400 controls the operation of the inverter 310 to output a second AC power, which includes pulsations corresponding to the pulsations of power flowing from the converter 130 (rectifier unit) to the capacitor 210, to the motor 314 (load). The pulsations corresponding to the pulsations of power flowing into the capacitor 210 are, for example, pulsations that fluctuate depending on the frequency of the pulsations of power flowing into the capacitor 210. As a result, the control unit 400 suppresses the current flowing into the capacitor 210. Note that the control unit 400 does not need to use all the detection values ​​obtained from each detection unit, and may perform control using only some of the detection values.

[0081] The operation of the control unit 400 of the power converter 1 will now be described. In this embodiment, the load generated by the inverter 310 and the motor 314 in the power converter 1 can be considered as a constant load, and in terms of the current output from the capacitor 210, it will be assumed that a constant current load is connected to the capacitor 210 for the following explanation. Here, as shown in Figure 21, the current flowing from the converter 130 will be current I1, the current flowing to the inverter 310 will be current I2, and the current flowing from the capacitor 210 will be current I3. Current I2 is the sum of current I1 and current I3. Current I3 can be expressed as the difference between current I2 and current I1, i.e., current I2 - current I1. Current I3 assumes that the discharge direction of the capacitor 210 is positive and the charging direction of the capacitor 210 is negative. That is, current may flow into the capacitor 210 and current may flow out.

[0082] Figure 22 shows examples of currents I1 to I3 and the capacitor voltage Vdc of capacitor 210 when the current output from converter 130 is smoothed by capacitor 210 and the current I2 flowing through inverter 310 is kept constant, as a comparative example. From top to bottom, it shows current I1, current I2, current I3, and the capacitor voltage Vdc of capacitor 210 generated in accordance with current I3. The vertical axes for currents I1, I2, and I3 show the current values, and the vertical axis for capacitor voltage Vdc shows the voltage values. The horizontal axis for all shows time t. Note that the carrier components of inverter 310 are actually superimposed on currents I2 and I3, but this is omitted here. The same applies to subsequent figures. As shown in Figure 22, in the power converter 1, if the current I1 flowing from converter 130 is sufficiently smoothed by capacitor 210, the current I2 flowing through inverter 310 will be a constant current value. However, a large current I3 flows through capacitor 210, which becomes a factor in degradation. Therefore, in this embodiment, in the power converter 1, the control unit 400 controls the current I2 flowing through the inverter 310, that is, controls the operation of the inverter 310, in order to reduce the current I3 flowing through the capacitor 210.

[0083] Figure 23 shows examples of currents I1 to I3 and the capacitor voltage Vdc of the capacitor 210 when the control unit 400 of the power converter 1 in the air conditioner 2 according to Embodiment 6 controls the operation of the inverter 310 to reduce the current I3 flowing through the capacitor 210. From top to bottom, the figures show current I1, current I2, current I3, and the capacitor voltage Vdc of the capacitor 210 generated in accordance with current I3. The vertical axes for currents I1, I2, and I3 show the current values, and the vertical axis for the capacitor voltage Vdc shows the voltage values. The horizontal axis for all figures shows time t. By controlling the operation of the inverter 310 so that the current I2 shown in Figure 23 flows through the inverter 310, the control unit 400 of the power converter 1 can reduce the frequency components of the current flowing from the converter 130 to the capacitor 210 and reduce the current I3 flowing through the capacitor 210, compared to the example in Figure 22. Specifically, the control unit 400 controls the operation of the inverter 310 so that a current I2, which includes a pulsating current whose main component is the frequency component of current I1, flows through the inverter 310.

[0084] Thus, in the power converter 1, the control unit 400 controls the operation of the inverter 310 so that the pulsation corresponding to the operating state detected by the operating state detection units 501 to 505 is superimposed on the drive pattern of the motor 314 connected to the inverter 310, which is a power converter, thereby suppressing the charging and discharging current of the capacitor 210. As a result, the air conditioner 2 can suppress the deterioration of the smoothing capacitor 210.

[0085] Embodiment 7. This section describes a control method that suppresses fluctuations in DC voltage even when the number of switching cycles of the short-circuit section that short-circuits the AC power supply, commercial power supply 110, is changed in accordance with load conditions, in the power conversion device 1 of Embodiments 1 to 3. Specifically, the power conversion device 1 of Embodiment 1 will be used as an example.

[0086] Figure 24 shows an example of the configuration of an air conditioner 2 according to Embodiment 7. The air conditioner 2 comprises a power converter 1 and a motor 314. The power converter 1 of Embodiment 7 shown in Figure 24 is modified from the power converter 1 of Embodiment 1 shown in Figure 1 by removing the converter 130 and capacitor 210 and adding a reactor 135, a rectifier section 170, and a short-circuit section 30. The rectifier section 170 consists of a rectifier circuit composed of four rectifier elements 131 to 134 and a capacitor 210 connected between the output terminals of the rectifier circuit to smooth the voltage of the full-wave rectified waveform output from the rectifier circuit. The rectifier section 170 rectifies and outputs the first AC power supplied from the commercial power supply 110.

[0087] The short-circuit section 30 short-circuits the commercial power supply 110 via the reactor 135. The short-circuit section 30 consists of a diode bridge 31 connected in parallel to the commercial power supply 110 via the reactor 135, and a short-circuit element 32 connected to both output terminals of the diode bridge 31. When the short-circuit element 32 is a metal-oxide-semiconductor field-effect transistor, the gate of the short-circuit element 32 is connected to the control unit 400, and the short-circuit element 32 is turned on and off by a drive signal from the control unit 400. When the short-circuit element 32 is turned on, the commercial power supply 110 is short-circuited via the reactor 135 and the diode bridge 31.

[0088] The control unit 400 controls the short-circuit operation of the short-circuit section 30. The control unit 400 controls the on / off switching of the short-circuit element 32 in current open-loop control in short-circuit operation mode so that the short-circuit section 30 is short-circuited at least twice during half a cycle of the power supply. Based on the load conditions, the control unit 400 short-circuits the short-circuit section 30 at least twice during half a cycle of the commercial power supply 110. As a result, even when the air conditioner 2 changes the number of switching cycles of the short-circuit section 30 that short-circuits the commercial power supply 110 in accordance with the load conditions, fluctuations in the DC voltage can be suppressed.

[0089] Embodiment 8. Figure 25 shows an example of the configuration of the air conditioner 900 according to Embodiment 8. The air conditioner 900 according to Embodiment 8 is intended to explain in more detail the configuration of the air conditioner 2 described in Embodiment 1. The air conditioner 900 according to Embodiment 8 may also be the air conditioner 2 described in Embodiments 2 to 7. In Figure 25, components having the same functions as those in Embodiment 1 are denoted by the same reference numerals as in Embodiment 1.

[0090] The air conditioner 900 has a compressor 315 with a 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, all of which are connected via refrigerant piping 912.

[0091] Inside the compressor 315 are a compression mechanism 904 for compressing the refrigerant and a motor 314 for operating the compression mechanism 904.

[0092] The air conditioner 900 can operate in heating or cooling mode by switching the four-way valve 902. The compression mechanism 904 is driven by a motor 314 that is controlled by variable speed control.

[0093] During heating operation, as indicated by the solid arrows, the refrigerant is pressurized by the compression mechanism 904 and sent out, then returns to the compression mechanism 904 after passing through the four-way valve 902, indoor heat exchanger 906, expansion valve 908, outdoor heat exchanger 910 and the four-way valve 902.

[0094] During cooling operation, as indicated by the dashed arrows, the refrigerant is pressurized by the compression mechanism 904 and sent out, then returns to the compression mechanism 904 after 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.

[0095] During heating operation, the indoor heat exchanger 906 acts as a condenser to release heat, and the outdoor heat exchanger 910 acts as an evaporator to absorb heat. During cooling operation, the outdoor heat exchanger 910 acts as a condenser to release heat, and the indoor heat exchanger 906 acts as an evaporator to absorb heat. The expansion valve 908 reduces the pressure of the refrigerant and causes it to expand.

[0096] In the power converter 1 of the air conditioner 900, the digital gate driver module, which consists of a waveform shape changing unit 340 and switching elements 311a to 311f included in the inverter 310, generates a large surge voltage and a lot of electromagnetic noise when the switching speed is fast. When the air conditioner 900 uses a flammable refrigerant, there is a possibility that the refrigerant may leak and ignite due to discharge caused by electromagnetic noise. Therefore, the air conditioner 900 sets the switching speed of the digital gate driver module in the power converter 1 according to the flammability of the refrigerant used in the air conditioner 900. For example, the more flammable the refrigerant used in the air conditioner 900, the slower the switching speed of the digital gate driver module in the power converter 1. By slowing the switching speed of the digital gate driver module, the air conditioner 900 can reduce the surge voltage and suppress the generation of discharge caused by electromagnetic noise, thereby preventing ignition even if the refrigerant leaks from the air conditioner 900.

[0097] The refrigerants used in the 900 air conditioner include, for example, R1234yf, R1234ze(E), R1243zf, HFO1123, HFO1132(E), R1132a, CF3I, R290, R463A, R466A, R454A, R454B, and R454C.

[0098] The configurations shown in the above embodiments are merely examples, and it is possible to combine them with other known technologies, combine different embodiments, and omit or modify parts of the configuration without departing from the gist of the invention. [Explanation of Symbols]

[0099] 1 Power converter, 2,900 Air conditioner, 11 Model deviation calculation unit, 12 Current estimator, 13 Subtractor, 14 Deviation calculator, 21 First angular velocity estimation unit, 22 Second angular velocity estimation unit, 23 Adder, 30 Short circuit, 31 Diode bridge, 32 Short circuit element, 101 Speed ​​estimation device, 110, 110a Commercial power supply, 130 Converter, 131~134, 131a~134a, 131b, 131c Rectifier element, 135, 135a~135c Reactor, 136, 136a~136d, 311a~311f Switching element, 137, 137a~137d, 312a~312f Freewheeling 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, 501-505 operating state detection unit, 902 four-way valve, 904 compression mechanism, 906 indoor heat exchanger, 908 expansion valve, 910 outdoor heat exchanger, 912 refrigerant piping.

Claims

1. An air conditioner that controls the air conditioning system, One or more switching elements included in at least one of the power converters that perform power conversion, A waveform shape changing unit that can change the waveform shape of the switching waveform of the switching element without physically switching the gate resistor, The operating state detection unit detects the operating state of the air conditioner, A basic pulse generation unit that determines the timing for turning on and turning off the switching element based on the aforementioned operating state, Based on the aforementioned operating state, the waveform shape of the switching waveform at the timing for turning on and turning off the switching element determined by the basic pulse generation unit is set, and the waveform shape control signal output unit outputs a control signal to the waveform shape changing unit that can change the magnitude and output timing of the drive signal according to the set waveform shape. Equipped with, The waveform shape changing unit is a digital gate driver, and changes the waveform shape of the switching waveform of the switching element based on the control signal obtained from the waveform shape control signal output unit. The aforementioned operating state also utilizes information regarding the set temperature for the air conditioner and the operating mode of the air conditioner. Air conditioner.

2. An air conditioner that controls the air conditioning system, One or more switching elements included in at least one of the power converters that perform power conversion, A plurality of transistors mounted to drive the switching element, and a waveform shape changing unit capable of changing the waveform shape of the switching waveform of the switching element by changing the number of transistors that are operated, The operating state detection unit detects the operating state of the air conditioner, A basic pulse generation unit that determines the timing for turning on and turning off the switching element based on the aforementioned operating state, Based on the aforementioned operating state, the waveform shape of the switching waveform at the timing for turning on and turning off the switching element determined by the basic pulse generation unit is set, and the waveform shape control signal output unit outputs a control signal to the waveform shape changing unit that can change the magnitude and output timing of the drive signal according to the set waveform shape. Equipped with, The waveform shape changing unit is a digital gate driver, and changes the waveform shape of the switching waveform of the switching element based on the control signal obtained from the waveform shape control signal output unit. The aforementioned operating state also utilizes information regarding the set temperature for the air conditioner and the operating mode of the air conditioner. Air conditioner.

3. The waveform shape changing unit, based on the control signal output from the waveform shape control signal output unit, divides at least one of the turn-on and turn-off periods of the switching element into two or more periods, and changes the amplitude of the gate current or gate voltage to the switching element to a different magnitude in each divided period, thereby making it possible to change the noise and loss generated in the switching element according to the operating state. The air conditioner according to claim 1 or 2.

4. The waveform shape changing unit changes the waveform shape of the switching waveform of the switching element while at least one of the compressor motor and fan motor of the air conditioner is rotating. The air conditioner according to claim 1 or 2.

5. The waveform shape control signal output unit outputs a control signal to the waveform shape changing unit to change the waveform shape of the switching waveform of the switching element in order to suppress the losses when the operating state is light load operation below a specified load, and outputs a control signal to the waveform shape changing unit to change the waveform shape of the switching waveform of the switching element in order to suppress the noise when the operating state is heavy load operation above a specified load. The air conditioner according to claim 3.

6. If the operating conditions are intermediate cooling conditions or intermediate heating conditions, the operation shall be light load operation; if the operating conditions are rated cooling conditions, rated heating conditions, or other air temperature conditions, the operation shall be heavy load operation. The air conditioner according to claim 5.

7. If the difference between the ambient temperature and the set temperature of the air conditioner is less than a specified threshold, the system will operate in light load mode; if the difference between the ambient temperature and the set temperature of the air conditioner is equal to or greater than a specified threshold, the system will operate in heavy load mode. The air conditioner according to claim 5.

8. The power converter is an inverter, and when at least one of the load current and load power output from the inverter is below a specified threshold, it is operated under light load conditions, and when at least one of the load current and load power output from the inverter is equal to or greater than a specified threshold, it is operated under heavy load conditions. The air conditioner according to claim 5.

9. If at least one of the input current and input power input to the power converter is below a specified threshold, the power converter will operate under light load conditions. If at least one of the input current and input power input to the power converter is equal to or greater than a specified threshold, the power converter will operate under heavy load conditions. The air conditioner according to claim 5.

10. 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. The air conditioner according to claim 1 or 2.

Images