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

air conditioner

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

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

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

[0004] The inverter control device described in Patent Document 1 is applied to an air conditioner and operates by changing the switching speed of the switching elements, taking into account both noise and loss generated depending on the operating state of the air conditioner. However, the inverter control device described in Patent Document 1 changes the switching speed of the switching elements by changing the gate resistance value of the gate resistor, but there is a limit to the number of gate resistance values. Therefore, depending on the operating state of the air conditioner, the inverter control device described in Patent Document 1 has a problem in that it may not be possible to optimize the switching speed of the switching elements, and may not be able to control noise and loss generation to the desired state.

[0005] The present disclosure has been made in view of the above, and has an object to provide an air conditioner that is capable of controlling the generation of noise and loss depending on the operating state.

[0006] In order to solve the above-mentioned problems and achieve the object, the present disclosure provides an air conditioner that performs air conditioning control, the air conditioner including one or more switching elements included in at least one of 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 elements, an operating state detection unit that detects the operating state of the air conditioner, and 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 elements according to the operating state.

[0007] The air conditioner according to the present disclosure has the advantage of being able to control the generation of noise and loss according to the operating state.

[0008] FIG. 1 is a diagram showing an example of the configuration of an air conditioner according to embodiment 1. 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 the inverter switching element is slowed down in the power conversion device of the air conditioner according to embodiment 1. 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 the inverter switching element is fastened in the power conversion device of the air conditioner according to embodiment 1.and turn-on voltage. Figure showing an example of the relationship between noise and loss generated in a general switching element. Figure 1 shows the effect obtained by changing the switching speed of the inverter switching element in the power conversion device for an air conditioner according to embodiment 1. Figure 2 shows the effect obtained by changing the switching speed of the inverter switching element in the power conversion device for an air conditioner according to embodiment 1. Figure 1 shows the relationship between the gate current output by the waveform shape changing unit and the gate voltage indicating the rise speed of the switching element in the power conversion device for an air conditioner according to embodiment 1. Figure 2 shows the relationship between the gate current output by the waveform shape changing unit and the gate voltage indicating the rise speed of the switching element in the power conversion device for an air conditioner according to embodiment 1. FIG. 3 is a diagram showing an example of the relationship between the basic pulse output by the basic pulse generating unit and the gate current output by the waveform shape changing unit in a power conversion device provided in an air conditioner according to embodiment 1. FIG. 4 is a flowchart showing the operation of changing the waveform shape of the switching waveform of a switching element in a power conversion device provided in an air conditioner according to embodiment 1. FIG. 5 is a diagram showing an example of the hardware configuration for realizing the control unit provided in the power conversion device of an air conditioner according to embodiment 1. FIG. 6 is a diagram showing an example of the configuration of an air conditioner according to embodiment 2. FIG. 7 is a diagram showing an example of the configuration of an air conditioner according to embodiment 3. FIG. 8 is a diagram showing an example of the configuration of an air conditioner according to embodiment 5. FIG. 9 is a diagram showing an example of the configuration of an air conditioner according to embodiment 6. As a comparative example, a capacitor is used to smooth the current output from the converter,FIG. 1 shows an example of each current and the capacitor voltage of the capacitor when the current flowing through the inverter is kept constant. FIG. 2 shows an example of each current and the capacitor voltage of the capacitor when the control unit of the power conversion device provided in the air conditioner according to embodiment 6 controls the operation of the inverter to reduce the current flowing through the capacitor. FIG. 3 shows an example of the configuration of an air conditioner according to embodiment 7. FIG. 4 shows an example of the configuration of an air conditioner according to embodiment 8.

[0009] Hereinafter, an air conditioner according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0010] Embodiment 1. FIG. 1 is a diagram showing an example of the configuration of an air conditioner 2 according to Embodiment 1. The air conditioner 2, which controls air conditioning, includes a power conversion device 1 and a motor 314. The power conversion device 1 is connected to a commercial power source 110 and the motor 314. The power conversion device 1 converts first AC power of a power source voltage Vs supplied from the commercial power source 110 into second AC power having a desired amplitude and phase, and supplies the second AC power to the motor 314. In the example of FIG. 1 , the commercial power source 110 is a single-phase AC power source, but may be a three-phase AC power source. The power conversion device 1 includes 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, etc.

[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 includes rectifying elements 131 to 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 formed by rectifying elements 131 to 134, rectifies first AC power of power supply voltage Vs supplied from commercial power supply 110, and boosts and outputs the rectified DC power. Drive circuit 150 generates a drive signal for actually driving switching element 136, based on a basic pulse generated by a basic pulse generating unit 410 of control unit 400 (described later). The switching element 136 may be, for example, an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET), a bipolar transistor, or the like, but is not limited to these. The configuration of the converter 130 is not limited to the example shown in FIG. 1 . In the converter 130, one or more of the rectifying elements 131 to 134 may be configured with a switching element. In the power conversion device 1 of the first embodiment shown in FIG. 1 , the converter 130 may have only a rectifying function and may not have a boosting function. In addition, when the commercial power supply 110 is a three-phase AC power supply, the converter 130 is configured to include six rectifying elements.

[0013] Capacitor 210 is connected to the output terminal of converter 130 and smoothes 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 to both ends of the capacitor 210. The inverter 310 includes switching elements 311a to 311f and freewheeling diodes 312a to 312f. The inverter 310 turns on and off the switching elements 311a to 311f under the control of the control unit 400, converts the power output from the converter 130 and the capacitor 210 into second AC power having a desired amplitude and phase, i.e., generates second AC power, and outputs it to the motor 314. The switching elements 311a to 311f are, for example, 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. In addition, in this embodiment, the inverter 310 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 modification unit 340 is capable of outputting 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 modification unit 340 is configured to be able to modify the waveform shapes of the switching waveforms of the switching elements 311a to 311f, but it is also possible to modify the waveform shape of the switching waveform of at least one of the switching elements 311a to 311f. Furthermore, the inverter 310 may be configured to include a waveform shape modification unit 340 for each of the switching elements 311a to 311f. The detailed operation of the waveform shape modification 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 motor 314, which is a load, and the current value of the second AC power supplied from the inverter 310 to the motor 314, which is a load. 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. 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.

[0017] The control unit 400 acquires the operating states detected by the operating state detection units 501 to 505 from the operating state detection units 501 to 505, and controls the operations of the converter 130 and the inverter 310 based on the acquired operating states, specifically, controls the on / off of the switching element 136 of the converter 130, and controls the on / off of the switching elements 311a to 311f of the inverter 310. The control unit 400 includes a basic pulse generation unit 410 and a waveform shape control signal output unit 420.

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

[0019] The waveform shape control signal output unit 420 sets the waveform shapes of the switching waveforms of the switching elements 311a to 311f when the waveform shape modification unit 340 of the inverter 310 changes the switching waveforms of the switching elements 311a to 311f in accordance with 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 for controlling the operation of the switching elements 311a to 311f of the inverter 310 generated by the basic pulse generation unit 410, the waveform shape control signal output unit 420 controls the magnitude of the drive signals that the waveform shape modification unit 340 of the inverter 310 outputs to the switching elements 311a to 311f to actually drive the switching elements 311a to 311f, and the timing at which the drive signals are output. The waveform shape control signal output unit 420 outputs a control signal for controlling the operation of the waveform shape modification unit 340 to the waveform shape modification unit 340. When the inverter 310 has a waveform shape modification unit 340 for each of the switching elements 311a to 311f, i.e., six waveform shape modification units 340, the control unit 400 may be configured to have a waveform shape control signal output unit 420 for each waveform shape modification unit 340, i.e., six waveform shape control signal output units 420.

[0020] In the example of FIG. 1 , the control unit 400 acquires the operating states detected by the operating state detection units 501-505 from the operating state detection units 501-505 and controls the operation of the converter 130 and the inverter 310 based on the acquired operating states, but this is not limited to this. The control unit 400 can control the operation of the converter 130 and the inverter 310 based on the operating state acquired from at least one of the operating state detection units 501-505. In the power conversion device 1, the operating state detection units 501-505 detect, as the operating state, 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., but the detection targets are not limited to these. Furthermore, the installation locations of the operating state detection units 501-505 are not limited to the example of FIG. 1 . The power conversion device 1 does not need to have all of the operating state detection units 501-505 arranged as shown in FIG. 1 . The power conversion device 1 may have the operating state detection unit located anywhere other than the location shown in the figure, as long as the operating state can be detected. The power conversion device 1 may have the operating state detection unit located at a position where it can detect operating states such as noise generated by the power conversion device 1, the motor 314, etc., losses generated by the power conversion device 1, the motor 314, etc., and temperatures of each component of the power conversion device 1, the motor 314, etc. Furthermore, the control unit 400 can use, as the operating state of the air conditioner 2, information such as the set temperature for the air conditioner 2 and the operating mode of the air conditioner 2, such as heating or cooling, acquired from a remote controller (not shown) used by a user, etc.

[0021] Furthermore, since the basic pulse generating unit 410 and the waveform shape control signal output unit 420 both operate based on the operating state obtained from the operating state detection units 501 to 505, the control unit 400 may combine the functions of the basic pulse generating unit 410 and the waveform shape control signal output unit 420 into a single configuration.

[0022] The motor 314 is a load connected to the power conversion device 1. The motor 314 is, for example, a compressor motor for driving a compressor. The motor 314 rotates in accordance with the amplitude and phase of the second AC power supplied from the inverter 310 to perform compression. For example, when the compressor is a hermetic 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. The motor 314 may have a Y-connection, a Δ-connection, or a specification that allows switching between the Y-connection and the Δ-connection, with respect to the motor windings (not shown). Furthermore, the load connected to the power conversion device 1, i.e., the inverter 310, is not limited to the motor 314 for driving a compressor, but may also be a fan motor used in the air conditioner 2, for example. That is, the motor 314 is a compressor motor, a fan motor, or the like.

[0023] In this 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 by the waveform shape control signal output unit 420 and the waveform shape modification unit 340. Specifically, the power conversion device 1 can change the switching speed, delay time, etc. of the switching elements 311a to 311f of the inverter 310.

[0024] FIG. 2 is a diagram showing 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 in the power conversion device 1 of the air conditioner 2 according to embodiment 1. FIG. 3 is a diagram showing examples of turn-on joule loss, turn-on current, and turn-on voltage when the switching speed of the switching elements 311a to 311f of the inverter 310 is fast in the power conversion device 1 of the air conditioner 2 according to embodiment 1. In FIGS. 2 and 3, A represents turn-on joule loss, B represents turn-on current, and C represents turn-on voltage. In FIGS. 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, and may be the other switching elements 311b to 311f. 2 and 3 show differences in the characteristics of the switching elements 311a to 311f of the inverter 310 depending on the switching speed, and the specific values ​​of "slow" and "fast" switching speeds are not particularly important. As shown in FIGS. 2 and 3, slowing the switching speed reduces noise represented by the peak value of the turn-on current of B, but increases loss represented by the area of ​​the turn-on joule loss of A. Also, as shown in FIGS. 2 and 3, increasing the switching speed increases noise represented by the peak value of the turn-on current of B, but decreases loss represented by the area of ​​the turn-on joule loss of A. In other words, there is a trade-off between the noise and loss generated by the switching elements 311a to 311f.

[0025] In the power conversion device 1, the waveform shape modification 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 modification unit 340 are configured by a digital gate driver module. This allows the power conversion device 1 to change the switching speed of the switching elements 311a to 311f of the inverter 310 by changing a command value in software without changing the hardware, and to control the noise and loss generated in the switching elements 311a to 311f to a desired state.

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

[0027] FIG. 5 is a first diagram illustrating the effect obtained by changing the switching speed of the switching elements 311a to 311f of the inverter 310 in the power conversion device 1 of the air conditioner 2 according to embodiment 1. Even if the power conversion device 1 is operating within the noise range specified for the product in which the power conversion device 1 is installed, i.e., the air conditioner 2, when the load state of the motor 314 changes from a light load to a heavy load, the curve showing the characteristics of the noise and loss generated by the switching elements 311a to 311f shifts upward to the upper right as shown in FIG. 5, resulting in an increase in noise. In other words, in the power conversion device 1, the heavier the load, the greater the noise. Therefore, the power conversion device 1 can reduce the noise generated by the switching elements 311a to 311f by slowing down the switching speed of the switching elements 311a to 311f.

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

[0029] 6 is a second diagram illustrating the effect obtained by changing the switching speed of the switching elements 311a to 311f of the inverter 310 in the power conversion device 1 of the air conditioner 2 according to embodiment 1. The power conversion device 1, specifically the waveform shape modification unit 340, divides, for example, the turn-on period or turn-off period of a single switching operation of the switching elements 311a to 311f into two or more periods, and modifies the amplitude of the gate current or gate voltage for the switching elements 311a to 311f to different magnitudes in each divided period. By optimizing the switching waveforms of the switching elements 311a to 311f as shown in FIG. 6, the power conversion device 1 can obtain noise and loss characteristics that are generated by the switching elements 311a to 311f, which are not obtainable with typical switching elements such as those shown in FIG. 4.

[0030] The configuration of the waveform shape modification unit 340 will now be described. For ease of explanation, a case will be described in which the waveform shape modification unit 340 is capable of modifying the waveform shape of the switching waveform of one switching element 311a. Fig. 7 is a diagram showing a configuration example of the waveform shape modification unit 340 of the power conversion device 1 included in the air conditioner 2 according to the first embodiment. Fig. 7 also shows a configuration example of one digital gate driver module configured by the waveform shape modification unit 340 and the switching element 311a. As shown in Fig. 1 , the waveform shape modification 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 (PMOSs) for turn-on, n PreDrivers for operating the n PMOSs, n N-channel MOSFETs (NMOSs) for turn-off, and n PreDrivers for operating the n NMOSs.

[0031] The waveform shape changing unit 340 is connected to a control power supply Vdd and a ground GND. The waveform shape changing unit 340 changes the number of PMOS or NMOS transistors to be operated based on a control signal from the waveform shape control signal output unit 420, thereby changing the gate current I, which is a drive signal to be output to the switching element 311a, during each of the turn-on period and the turn-off period. Ｇ The waveform shape changing unit 340 can change the amplitude value of the gate current I output to the switching element 311a in n ways, thereby adjusting the switching speed of the switching element 311a. Ｇ The absolute value of can be increased, and the switching speed of the switching element 311a can be increased. In addition, the waveform shape changing unit 340 can adjust the switching speed of the switching element 311a more precisely as the number of PMOS and NMOS included therein increases, and the gate current I Ｇ The faster the response of the increase or decrease of the gate current IＧ It is possible to adjust the number of PMOS or NMOS transistors operated by the waveform shape modification unit 340. The control signal from the waveform shape control signal output unit 420 may be an analog signal or a digital signal as long as it can change the number of PMOS or NMOS transistors operated by the waveform shape modification unit 340. In addition, the example of FIG. 7 shows that there are m parallel control signals from the waveform shape control signal output unit 420 to the waveform shape modification 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 any number that can indicate whether each PMOS transistor and each NMOS transistor is operable or not, or it may be one signal as long as it is an analog signal that indicates a voltage or the like.

[0032] FIG. 8 shows the gate current I output by the waveform shape changing unit 340 in the power conversion device 1 provided in the air conditioner 2 according to the first embodiment. Ｇ and the gate voltage V, which indicates the rise speed of the switching element 311a. Ｇ 9 is a first diagram showing the relationship between the gate current I output by the waveform shape modification unit 340 in the power conversion device 1 provided in the air conditioner 2 according to the first embodiment. Ｇ and the gate voltage V, which indicates the rise speed of the switching element 311a. Ｇ 8 and 9, the waveform shape changing unit 340 changes the gate current I Ｇ The larger the gate voltage V Ｇ 8 and 9, the waveform shape changing unit 340 can increase the rise time of the output gate current I Ｇ The smaller the gate voltage V Ｇ 5, the power conversion device 1 can output a gate current I when it is desired to reduce noise generated by the switching element 311a. Ｇ When it is desired to reduce the loss occurring in the switching element 311a by decreasing the switching speed, the output gate current I ＧThe switching speed can be increased by increasing the gate current I Ｇ and gate voltage V Ｇ The waveform of the gate current I is an ideal example, and in reality, as shown in FIGS. Ｇ It takes time for the current to reach a constant value.

[0033] FIG. 10 shows the gate current I output by the waveform shape changing unit 340 in the power conversion device 1 provided in the air conditioner 2 according to the first embodiment. Ｇ and the gate voltage V, which indicates the rise speed of the switching element 311a. Ｇ 10, the waveform shape changing unit 340 divides the turn-on period and changes the gate current I Ｇ That is, the waveform shape changing section 340 can change the magnitude of the gate current I Ｇ This allows the power conversion device 1 to finely adjust the magnitude of the gate current I Ｇ 6, it is possible to perform control so as to reduce the loss generated in the switching element 311a while reducing the noise generated in the switching element 311a.

[0034] 8 to 10 have been 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. Fig. 11 shows the basic pulse output by the basic pulse generating unit 410 and the gate current I output by the waveform shape changing unit 340 in the power conversion device 1 provided in the air conditioner 2 according to the first embodiment. Ｇ 11 is a diagram illustrating an example of the relationship between |Ig2| and |Ig1|. In FIG. 11, |Ig2|>|Ig1|. The waveform shape changing unit 340 changes the gate current I Ｇ The period during which the current Ig2 having the larger amplitude is output is divided, and the gate current I Ｇ Then, the gate current I of the current Ig1 with the next smallest amplitude is output. Ｇ Alternatively, the gate current I of the current Ig1 with the small amplitude may be output first.Ｇ After outputting the gate current I of the current Ig2 with the next largest amplitude, Ｇ Similarly, the waveform shape changing unit 340 may output the gate current I Ｇ The period during which the current with the largest amplitude -Ig2 is output is divided, and the gate current I Ｇ Then, the gate current I of the next smallest amplitude current -Ig1 is output. Ｇ Alternatively, the gate current I of the current −Ig1 with a small amplitude may be output first. Ｇ After outputting the next largest current, the gate current Ig2 Ｇ may be output.

[0035] In this way, the waveform shape changing unit 340 divides at least one of the turn-on period and the turn-off period of the switching element 311a into two or more periods based on the control signal output from the waveform shape control signal output unit 420, and controls the gate current I for the switching element 311a in each divided period. Ｇ The waveform shape changing section 340 includes a plurality of transistors, and by changing the number of transistors to be operated based on the control signal output from the waveform shape control signal output section 420, the amplitude of the gate current I Ｇ This allows the air conditioner 2 to change the noise and loss generated in the switching element 311a depending on the operating state.

[0036] Furthermore, the waveform shape changing unit 340 changes the gate current I ＧThe waveform shape modification unit 340 can change the output pattern of the switching element 311a. During operation of the power conversion device 1, the waveform shape modification unit 340 can change the switching waveform of the switching element 311a to a different waveform shape for each switching period of the switching element 311a. For example, the waveform shape modification unit 340 changes the waveform shape of the switching waveform of the switching element 311a while at least one of the motors 314 provided in the air conditioner 2, such as a compressor motor or a 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 period as the switching period 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 period that is a positive integer multiple of the switching period of the switching element 311a.

[0037] 7 is merely an example and is not intended to be limiting. In this manner, the waveform shape modification unit 340 can more precisely adjust the switching speed of the switching element 311a by digital control using a plurality of MOS (Metal Oxide Semiconductors), compared to analog control that physically switches gate resistors as described in Patent Document 1. Furthermore, the waveform shape modification unit 340 may use transistors other than MOS transistors for its internal transistors.

[0038] In the above example, the waveform shape changing unit 340 changes the number of PMOS or NMOS to be operated in accordance with the acquired control signal, and generates a gate current I Ｇ to the switching element 311a, but is not limited to this. The waveform shape changing unit 340 changes the gate current I Ｇ The output pattern, i.e., waveform shape, of the gate current I is stored in advance, and the output pattern, i.e., waveform shape, corresponding to the acquired control signal is output. Ｇ Furthermore, the waveform shape changing unit 340 may output a previously acquired control signal and a gate current I ＧThe output pattern, i.e., waveform shape, of the gate current I is stored in memory, and when the same control signal is acquired, the stored output pattern, i.e., waveform shape is used. Ｇ The waveform shape changing section 340 may output the gate current I Ｇ By storing the output pattern, i.e., waveform shape, of the gate current I Ｇ This reduces the processing load when outputting.

[0039] In the example of FIG. 7, the waveform shape changing unit 340 changes the gate current I Ｇ The waveform shape changing unit 340 adjusts the switching speed of the switching element 311a by changing the gate voltage V Ｇ and the gate voltage V Ｇ By changing the value of the switching speed of the switching element 311a, the switching speed of the switching element 311a can be adjusted and the waveform shape of the switching waveform of the switching element 311a can be changed.

[0040] In this way, the waveform shape changing unit 340 divides at least one of the turn-on period and the turn-off period of the switching element 311a into two or more periods based on the control signal output from the waveform shape control signal output unit 420, and changes the gate voltage V Ｇ The waveform shape changing section 340 includes a plurality of transistors, and by changing the number of transistors to be operated based on the control signal output from the waveform shape control signal output section 420, the amplitude of the gate voltage V Ｇ This allows the air conditioner 2 to change the noise and loss generated in the switching element 311a depending on the operating state.

[0041] 12 is a flowchart showing an operation of changing the waveform shape of the switching waveforms of the switching elements 311a to 311f in the power conversion device 1 provided in the air conditioner 2 according to embodiment 1. 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 operating state obtained from the operating state detection units 501 to 505 (step S1). As described above, in the control unit 400, the basic pulse generation unit 410 generates basic pulses based on the operating state obtained from the operating state detection units 501 to 505, and determines the timings for turning on and 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 a waveform shape for changing the waveform shape of the switching waveform of the switching elements 311a to 311f of the inverter 310, based on the basic pulse acquired from the basic pulse generation unit 410 and the operating state acquired from the operating state detection units 501 to 505. In this way, in the control unit 400, the waveform shape control signal output unit 420 sets the waveform shapes of the switching waveforms at the timings for turning on and off the switching elements 311a to 311f determined by the basic pulse generation unit 410, based on the operating state acquired from the operating state detection units 501 to 505. The waveform shape control signal output unit 420 outputs a control signal to the waveform shape change unit 340, which can change the magnitude and output timing of the drive signal in accordance with the set waveform shape (step S2).

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

[0044] Next, a description will be given of the hardware configuration of the control unit 400 provided in the power conversion device 1. Fig. 13 is a diagram showing an example of a hardware configuration realizing the control unit 400 provided in the power conversion device 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 called a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, or DSP (Digital Signal Processor)) or a system LSI (Large Scale Integration). Examples of memory 92 include non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory). Memory 92 is not limited to these, and may also be a magnetic disk, optical disk, compact disk, minidisc, or DVD (Digital Versatile Disc).

[0046] 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 waveforms of the switching elements 311a to 311f in the waveform shape changing unit 340 of the inverter 310, in accordance with the operating state detected by the operating state detection units 501 to 505. The waveform shape changing unit 340 of the inverter 310 changes the gate current I to be output to the switching elements 311a to 311f based on the control signal output from the waveform shape control signal output unit 420. Ｇ or gate voltage V ＧBy changing the gate current I output to the switching elements 311a to 311f in one switching period, the waveform shape of the switching waveform of the 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 state. Furthermore, the air conditioner 2 can change the switching speed of the switching elements 311a to 311f while suppressing an increase in circuit size. The air conditioner 2 changes the gate current I output to the switching elements 311a to 311f in one switching period. Ｇ or gate voltage V Ｇ By finely adjusting the waveforms, it is possible to realize the waveform shapes of the switching waveforms of the switching elements 311a to 311f that could not be realized by the method of Patent Document 1 and the like.

[0047] 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 of the air conditioner 2. 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 of the air conditioner 2.

[0048] 14 is a diagram showing an example configuration of an air conditioner 2 according to Embodiment 2. The air conditioner 2 includes a power conversion device 1 and a motor 314. The power conversion device 1 is connected to a commercial power supply 110 and the motor 314. The power conversion device 1 converts first AC power of a 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 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 conversion device 1 of the second embodiment shown in FIG. 14 is configured by removing the waveform shape modification unit 340 from the inverter 310 and adding a drive circuit 350, and removing the drive circuit 150 from the converter 130 and adding a waveform shape modification unit 140. The power conversion device 1 of the second embodiment shown in FIG. 14 also differs from the power conversion device 1 of the first embodiment shown in FIG. 1 in that the output destinations of the basic pulse generation unit 410 and the waveform shape control signal output unit 420 are changed. Specifically, the basic pulse generation unit 410 outputs a basic pulse for controlling the operation of the switching element 136 of the converter 130 to the waveform shape control signal output unit 420, and outputs a basic pulse for controlling the operation of the switching elements 311a to 311f of the inverter 310 to the inverter 310. The waveform shape control signal output unit 420 also outputs a control signal for controlling the operation of the waveform shape modification unit 140 to the waveform shape modification unit 140.

[0050] 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 generating section 410 of the control section 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 modification unit 140 of the converter 130 changes the switching waveform of the switching element 136, in accordance with 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 pulse for controlling the operation of the switching element 136 of the converter 130 generated by the basic pulse generation unit 410, the waveform shape control signal output unit 420 controls the magnitude of the drive signal that the waveform shape modification unit 140 of the converter 130 outputs to the switching element 136 to actually drive the switching element 136, and the timing at which the drive signal is output. The waveform shape control signal output unit 420 outputs a control signal for controlling the operation of the waveform shape modification unit 140 to the waveform shape modification unit 140.

[0052] The waveform shape modification unit 140 is capable of modifying the waveform shape of the switching waveform of the switching element 136. The waveform shape modification unit 140 is capable of outputting two or more waveform shapes as the waveform shape of the switching waveform of the switching element 136. As shown in FIG. 14 , the waveform shape modification unit 140 is included in a converter 130, which is a power converter including the switching element 136. The configuration of the waveform shape modification unit 140 is similar to the configuration of the waveform shape modification unit 340 of the first embodiment shown in FIG. 7 . That is, the waveform shape modification unit 140 and the switching element 136 are configured by one digital gate driver module. Similarly to the waveform shape modification unit 340, the waveform shape modification unit 140 also outputs the 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 may be adjusted.

[0053] In this way, the waveform shape changing unit 140 divides at least one of the turn-on period and the turn-off period of the switching element 136 into two or more periods based on the control signal output from the waveform shape control signal output unit 420, and controls the gate current I to the switching element 136 in each divided period. Ｇ or gate voltage V Ｇ The waveform shape changing section 140 includes a plurality of transistors, and by changing the number of transistors to be operated based on the control signal output from the waveform shape control signal output section 420, the amplitude of the gate current I Ｇ or gate voltage V Ｇ As a result, the power conversion device 1 performs the same operation as in the first embodiment, and thereby the waveform shape control signal output unit 420 and the waveform shape modification unit 140 can modify the waveform shape of the switching waveform of the switching element 136 of the converter 130. Furthermore, the air conditioner 2 can modify the noise and loss generated in the switching element 136 depending on the operating state.

[0054] 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 element 136 in the waveform shape changing unit 140 of the converter 130, in accordance with the operating state detected by the operating state detection units 501 to 505. The waveform shape changing unit 140 of the converter 130 changes the gate current I to be output to the switching element 136 based on the control signal output from the waveform shape control signal output unit 420. Ｇ or gate voltage V Ｇ , thereby changing the waveform shape of the switching waveform of the switching element 136. The waveform shape changing unit 140 can change the waveform shape of the switching waveform of the switching element 136 in the same way that the waveform shape changing unit 340 of the first embodiment changes the waveform shape of the switching waveform of the switching element 311a. This allows the air conditioner 2 to control the occurrence of noise and loss according to the operating state. Furthermore, 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 changes the gate current I output to the switching element 136 in one switching period. Ｇ or gate voltage V Ｇ By finely adjusting the value, it is possible to realize a waveform shape of the switching waveform of the switching element 136 that could not be realized by the method of Patent Document 1 and the like.

[0055] In this embodiment, the configuration of the converter 130 for which the waveform shape of the switching elements is changed is not limited to the example shown in FIG. 14 . FIG. 15 is a first diagram illustrating a rectifying portion of the converter 130 included in the power conversion device 1 of the air conditioner 2 according to embodiment 2. FIG. 16 is a second diagram illustrating the rectifying portion of the converter 130 included in the power conversion device 1 of the air conditioner 2 according to embodiment 2. FIG. 17 is a third diagram illustrating the rectifying portion of the converter 130 included in the power conversion device 1 of the air conditioner 2 according to embodiment 2. FIGS. 15 to 17 only illustrate differences from FIG. 14 , and omit the illustration of the waveform shape change unit 140. As shown in FIG. 15 , in a configuration in which the converter 130 includes a reactor 135, switching elements 136a to 136d, and freewheel diodes 137a to 137d, the waveform shape change unit 140 may change the waveform shapes of the switching waveforms of the switching elements 136a to 136d. 16, in a configuration in which converter 130 includes reactor 135, rectifying elements 131 to 134, switching element 136, freewheel diode 137, and rectifying elements 131a to 134a, waveform shape modification unit 140 may change the waveform shape of the switching waveform of switching element 136. In a configuration in which the connected commercial power source is commercial power source 110a, which is a three-phase AC power source, and converter 130 includes reactors 135a to 135c, rectifying elements 131a to 131c, switching elements 136a to 136c, and freewheel diodes 137a to 137c, waveform shape modification unit 140 may change the waveform shape of the switching waveform of switching elements 136a to 136c.

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

[0057] 18 is a diagram showing an example configuration of an air conditioner 2 according to Embodiment 3. The air conditioner 2 includes a power conversion device 1 and a motor 314. The power conversion device 1 is connected to a commercial power supply 110 and the motor 314. The power conversion device 1 converts first AC power of a 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 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 conversion device 1 of the third embodiment shown in FIG. 18 is configured by removing the drive circuit 150 from the converter 130 and adding a waveform shape modification unit 140 to the power conversion device 1 of the first embodiment shown in FIG. 1 . Furthermore, the power conversion device 1 of the third embodiment shown in FIG. 18 has output destinations of the basic pulse generation unit 410 and the waveform shape control signal output unit 420 changed from those of the power conversion device 1 of the first embodiment shown in FIG. 1 . Specifically, the basic pulse generation unit 410 outputs a basic pulse for controlling the operation of the switching elements 311a to 311f of the inverter 310 to the waveform shape control signal output unit 420, and outputs a basic pulse for controlling the operation of the switching element 136 of the converter 130 to the waveform shape control signal output unit 420. Furthermore, the waveform shape control signal output unit 420 outputs a control signal for controlling the operation of the waveform shape modification unit 340 to the waveform shape modification unit 340, and outputs a control signal for controlling the operation of the waveform shape modification unit 140 to the waveform shape modification unit 140.

[0059] In the present embodiment, the waveform shape control signal output unit 420 performs the operation described in the first embodiment as well as the operation described in the second embodiment. Furthermore, in the present embodiment, the waveform shape modification unit 340 performs the same operation as that described in the first embodiment, and the waveform shape modification unit 140 performs the same operation as that described in the second embodiment. As a result, by performing the same operation as in the first embodiment, the power conversion device 1 can change the waveform shape of the switching waveform of the switching elements 311a to 311f of the inverter 310 by the waveform shape control signal output unit 420 and the waveform shape modification unit 340. Furthermore, by performing the same operation as in the second embodiment, the power conversion device 1 can change the waveform shape of the switching waveform of the switching element 136 of the converter 130 by the waveform shape control signal output unit 420 and the waveform shape modification unit 140.

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

[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 when the waveform shape change unit 340 of the inverter 310 changes the switching waveforms of the switching elements 311a to 311f, and outputs a control signal when the waveform shape change unit 140 of the converter 130 changes the switching waveform of the switching element 136, in accordance with the operating state detected by the operating state detection units 501 to 505. The waveform shape change unit 340 of the inverter 310 controls the gate current I to be output to the switching elements 311a to 311f based on the control signal output from the waveform shape control signal output unit 420. Ｇ or gate voltage V Ｇ The waveform shape changing unit 140 of the converter 130 changes the waveform shape of the switching waveform of 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 the gate current I , 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 state. Furthermore, 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 changes the gate current I , which is output to the switching elements 311a to 311f and the switching element 136 in one switching period.Ｇ or gate voltage V Ｇ By finely adjusting the waveforms, it is possible to realize the waveform shapes of the switching waveforms of the switching elements 311a to 311f and the switching element 136, which could not be realized by the method of Patent Document 1 and the like.

[0062] Fourth Embodiment In the first to third embodiments, the power conversion device 1 of the air conditioner 2 changes the waveform shapes of the switching waveforms of the switching elements 311a to 311f and the switching element 136 in accordance with the load state of the motor 314 and the like mounted on the air conditioner 2. In the fourth embodiment, a method for determining the load state of the power conversion device 1 will be described. The following description will be made specifically using the power conversion device 1 of the first embodiment as an example.

[0063] The operating state of the air conditioner 2 varies greatly depending on the operating state. For example, in a room that is the target of air conditioning control by the air conditioner 2, when there is a large temperature difference between the user's set temperature, i.e., the user's desired temperature, and the current room temperature, the load on the power conversion device 1 installed in the air conditioner 2 increases. On the other hand, when there is a small temperature difference between the user's desired temperature and the current room temperature, the load on the power conversion device 1 installed in the air conditioner 2 decreases.

[0064] The power conversion device 1 can detect the load state, for example, the current flowing through each component and the voltage applied to each component, based on the values ​​detected by the operation state detection units 501 to 505. The power conversion device 1 can also detect the load state, for example, the temperature, based on the values ​​detected by a temperature sensor (not shown) in the indoor unit of the air conditioner 2 or the value detected by a temperature sensor (not shown) in the outdoor unit. The power conversion device 1 may include a temperature sensor around the inverter 310 board to detect the temperature around the inverter 310 board, or a temperature sensor around the motor 314 to detect the temperature around the motor 314. The power conversion device 1 can also directly or indirectly detect the load state, for example, the operating speed of the motor 314, such as the compressor motor or fan motor, based on a 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. In this way, the load state is obtained from at least one of the detection values ​​of 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] The power conversion device 1 can also determine the operating state of the air conditioner 2 according to the air conditioning conditions of the air conditioner 2. The air conditioning conditions of the air conditioner 2 include, for example, an intermediate cooling condition, a rated cooling condition, an intermediate heating condition, and a rated heating condition.

[0066] Immediately after the air conditioner 2 enters cooling operation mode due to user operation, the room temperature is far from the set temperature. The motor 314 used for the compressor and other components operates at high speed, resulting in a heavy workload. This state represents air conditioning conditions known as cooling rated conditions, and power consumption is high, i.e., a heavy load state. Once the air conditioner 2 has fully operated under cooling rated conditions, the room temperature and the set temperature have become close. The motor 314 used for the compressor and other components operates at low speed, resulting in a low workload state. This state represents air conditioning conditions known as intermediate cooling conditions, and power consumption is low, i.e., a low load state.

[0067] Furthermore, immediately after the air conditioner 2 enters the heating operation mode due to user operation, the room temperature is far from the set temperature. The motor 314 used for the compressor and other components operates at high speed, resulting in a heavy workload. This state represents an air conditioning condition known as a heating rated condition, in which power consumption is high, i.e., a heavy load state. When the air conditioner 2 has fully operated under the heating rated condition, the room temperature and the set temperature are close to each other. The motor 314 used for the compressor and other components shifts to a low speed, resulting in a low workload state. This state represents an air conditioning condition known as an intermediate heating condition, in which power consumption is low, i.e., a low load state. The air conditioning conditions of the air conditioner 2 also include an air conditioning condition known as a heating low temperature condition, which is an operating mode in an environment where the outdoor temperature is lower than that under the heating rated condition. The heating low temperature condition imposes a greater load and consumes even more power than the heating rated condition.

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

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

[0070] In addition, the waveform shape control signal output unit 420 may perform light load operation when at least one of the load current and load power output from the inverter 310, which is a power converter, is less than a specified threshold, and may perform heavy load operation when 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 performs light load operation when at least one of the input current and input power input to the inverter 310 or converter 130, which are power converters, is less than a specified threshold, and performs heavy load operation when at least one of the input current and input power input to the inverter 310 or converter 130, which are power converters, is equal to or greater than a specified threshold.

[0072] Fifth Embodiment A case will be described in which an adaptive observer is applied to the power conversion device 1 of any one of the first to fourth embodiments as sensorless control of the motor 314. Specifically, the power conversion device 1 of the first embodiment will be described as an example.

[0073] FIG. 19 is a diagram showing an example of the configuration of an air conditioner 2 according to embodiment 5. The air conditioner 2 includes a power conversion device 1 and a motor 314. The power conversion device 1 of embodiment 5 shown in FIG. 19 is obtained by adding a speed estimation device 101 to the power conversion device 1 of embodiment 1 shown in FIG. 1. Note that in FIG. 19, the converter 130, inverter 310, and control unit 400 within the power conversion device 1 are simply depicted. FIG. 20 is a diagram showing an example of the configuration of the speed estimation device 101 provided in the power conversion device 1 of the air conditioner 2 according to embodiment 5. The speed estimation device 101 estimates the rotational speed of the motor 314 using a voltage vector and a current vector applied to the motor 314 by an adaptive observer technique, and calculates an estimated angular velocity ω^ ｒ Output as

[0074] The speed estimation device 101 estimates the voltage vector, the current vector, and the estimated angular speed ω^ ｒ a model deviation calculation unit 11 that calculates a model deviation ε based on the model deviation ε, and a first estimated angular velocity ω^ that is a low-frequency component including a 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 estimator 21 that calculates a second estimated angular velocity ω^ as a high-frequency component of the actual angular velocity based on a specific high-frequency component included in the model deviation ε. ｒ２ and a second angular velocity estimator 22 that calculates the first estimated angular velocity ω^ ｒ１ The second estimated angular velocity ω^ ｒ２ By adding ｒ The velocity estimation device 101 is characterized in that it includes a second angular velocity estimation unit 22. The velocity estimation device 101 calculates the first estimated angular velocity ω^ ｒ１ and the second estimated angular velocity ω^ ｒ２ The sum of these values ​​is the estimated angular velocity ω^ ｒ The calculated value is fed back to the model deviation calculation unit 11 as a function of time.

[0075] The model deviation calculation unit 11 calculates the voltage vector, current vector, and estimated angular velocity ω^ of the motor 314. ｒ The model deviation calculator 14 includes 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 to calculate and output a current deviation vector, and a deviation calculator 14 that receives the current deviation vector as an input, extracts the orthogonal component of the estimated magnetic flux vector as a scalar quantity, and outputs this value as a 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 transforming the current deviation vector onto two axes of rotation 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, it is assumed that the motor 314 is a general interior permanent magnet synchronous AC motor, but the current estimator 12 can estimate the current in a similar manner even if the motor 314 is other than an interior permanent magnet synchronous AC motor, as long as the state equation can be formulated. Examples of the motor 314 other than an interior permanent magnet synchronous AC motor include a surface permanent magnet synchronous motor and an induction motor. Furthermore, although a rotary motor is described in this embodiment, the same technology can also be applied to a linear motor. The reason for this is that a linear motor can be interpreted as a rotary motor with an infinite rotor radius.

[0077] In this way, the air conditioner 2 can apply an adaptive observer to sensorless control of the motor 314.

[0078] Sixth Embodiment A case will be described in which control is performed in the power conversion devices 1 of the first to third embodiments, which can suppress deterioration of the smoothing capacitor 210 while suppressing an increase in the size of the device. Specifically, the power conversion device 1 of the first embodiment will be described 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 includes a power conversion device 1 and a motor 314. The configuration of the power conversion device 1 according to embodiment 6 shown in Figure 21 is the same as the configuration of the power conversion device 1 according to embodiment 1 shown in Figure 1. The converter 130 is a rectifier unit that has a bridge circuit made up of rectifying elements 131 to 134 and rectifies and outputs first AC power of 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 so that the inverter 310 outputs, to the motor 314, which is a load, second AC power including pulsation corresponding to the pulsation of the power flowing from the converter 130, which is a rectifier, to the capacitor 210. The pulsation corresponding to the pulsation of the power flowing into the capacitor 210 is, for example, pulsation that varies depending on the frequency of the pulsation of the power flowing into the capacitor 210. In this way, 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 ​​acquired from each detection unit, and may perform control using only some of the detection values.

[0081] The operation of the control unit 400 included in the power conversion device 1 will be described. In this embodiment, in the power conversion device 1, the load generated by the inverter 310 and the motor 314 can be considered to be a constant load, and the following description will be given assuming that a constant current load is connected to the capacitor 210 when viewed in terms of the current output from the capacitor 210. Here, as shown in FIG. 21 , the current flowing from the converter 130 is referred to as current I1, the current flowing to the inverter 310 is referred to as current I2, and the current flowing from the capacitor 210 is referred to as 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. The discharge direction of capacitor 210 is considered to be the positive direction of current I3, and the charge direction of capacitor 210 is considered to be the negative direction. That is, current may flow into or out of capacitor 210.

[0082] FIG. 22 shows an example 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 through the inverter 310 is kept constant, as a comparative example. From top to bottom, the diagram shows the currents I1, I2, I3, and the capacitor voltage Vdc of the capacitor 210 generated in response to the current I3. The vertical axes of the currents I1, I2, and I3 represent the current values, while the vertical axis of the capacitor voltage Vdc represents the voltage value. The horizontal axes all represent time t. Note that, although a carrier component of the inverter 310 is actually superimposed on the currents I2 and I3, it is omitted here. The same applies hereinafter. As shown in FIG. 22 , in the power conversion device 1, if the current I1 flowing from the converter 130 is sufficiently smoothed by the capacitor 210, the current I2 flowing through the inverter 310 will be a constant current value. However, a large current I3 flows through the capacitor 210, which can cause degradation. Therefore, in the present embodiment, in the power conversion device 1, the control unit 400 controls the current I2 flowing through the inverter 310, that is, controls the operation of the inverter 310, so as to reduce the current I3 flowing through the capacitor 210.

[0083] FIG. 23 is a diagram illustrating an example of the currents I1 to I3 and the capacitor voltage Vdc of the capacitor 210 when the control unit 400 of the power conversion device 1 included 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 diagram illustrates the currents I1, I2, I3, and the capacitor voltage Vdc of the capacitor 210 generated in response to the current I3. The vertical axes of the currents I1, I2, and I3 represent current values, and the vertical axis of the capacitor voltage Vdc represents voltage values. The horizontal axes all represent time t. By controlling the operation of the inverter 310 so that the current I2 shown in FIG. 23 flows through the inverter 310, the control unit 400 of the power conversion device 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 of FIG. 22 . Specifically, the control unit 400 controls the operation of the inverter 310 so that the current I2 including the pulsating current whose main component is the frequency component of the current I1 flows through the inverter 310 .

[0084] In this way, in the power conversion device 1, the control unit 400 controls the operation of the inverter 310, which is a power converter, so that 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, thereby suppressing the charge / discharge current of the capacitor 210. This allows the air conditioner 2 to suppress deterioration of the smoothing capacitor 210.

[0085] Seventh Embodiment A case will be described in which, in the power conversion devices 1 of the first to third embodiments, control is performed that can suppress fluctuations in DC voltage even when the number of switching times of the short-circuiting part that shorts the commercial power supply 110, which is an AC power supply, is changed in response to load conditions. Specifically, the power conversion device 1 of the first embodiment will be described as an example.

[0086] FIG. 24 is a diagram showing an example configuration of an air conditioner 2 according to a seventh embodiment. The air conditioner 2 includes a power conversion device 1 and a motor 314. The power conversion device 1 according to the seventh embodiment shown in FIG. 24 is configured by removing the converter 130 and the capacitor 210 from the power conversion device 1 according to the first embodiment shown in FIG. 1 and adding a reactor 135, a rectifying unit 170, and a short-circuiting unit 30. The rectifying unit 170 includes a rectifying circuit made up of four rectifying elements 131 to 134 and a capacitor 210 connected between the output terminals of the rectifying circuit to smooth the voltage of the full-wave rectified waveform output from the rectifying circuit. The rectifying unit 170 rectifies the first AC power supplied from the commercial power source 110 and outputs the rectified power.

[0087] The short-circuiting unit 30 short-circuits the commercial power supply 110 via the reactor 135. The short-circuiting unit 30 is composed of a diode bridge 31 connected in parallel to the commercial power supply 110 via the reactor 135, and a short-circuiting element 32 connected to both output terminals of the diode bridge 31. When the short-circuiting element 32 is a metal oxide semiconductor field effect transistor, the gate of the short-circuiting element 32 is connected to the control unit 400, and the short-circuiting element 32 is turned on and off by a drive signal from the control unit 400. When the short-circuiting 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-circuiting operation of the short-circuiting unit 30. The control unit 400 controls the on / off of the short-circuiting element 32 using current open-loop control in the short-circuiting operation mode so as to short-circuit the short-circuiting unit 30 at least twice during a half cycle of the power supply. The control unit 400 shorts the short-circuiting unit 30 at least twice during a half cycle of the commercial power supply 110 based on the load conditions. This allows the air conditioner 2 to suppress fluctuations in DC voltage even when the number of switching operations of the short-circuiting unit 30 that short-circuits the commercial power supply 110 is changed in response to the load conditions.

[0089] Embodiment 8 Fig. 25 is a diagram showing an example of the configuration of an 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 be the air conditioner 2 described in embodiments 2 to 7. In Fig. 25, components having the same functions as those in embodiment 1 are assigned the same reference numerals as those in embodiment 1.

[0090] The air conditioner 900 includes a compressor 315 incorporating the motor 314 in embodiment 1, a four-way valve 902, an indoor heat exchanger 906, an expansion valve 908, and an outdoor heat exchanger 910, which are attached via refrigerant piping 912.

[0091] Inside the compressor 315, a compression mechanism 904 that compresses the refrigerant and a motor 314 that operates the compression mechanism 904 are provided.

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

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

[0094] During cooling operation, as shown by the dashed arrow, the refrigerant is pressurized by the compression mechanism 904 and sent out, and returns to the compression mechanism 904 through the four-way valve 902, the outdoor heat exchanger 910, the expansion valve 908, the indoor heat exchanger 906 and the four-way valve 902.

[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 to expand it.

[0096] In the power conversion device 1 included in the air conditioner 900, the digital gate driver module, which is composed of the waveform shape modification 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 its switching speed is fast. When the air conditioner 900 uses a flammable refrigerant, there is a possibility that the refrigerant may leak and burn due to discharge caused by electromagnetic noise. Therefore, the air conditioner 900 sets the switching speed of the digital gate driver module included in the power conversion device 1 according to the flammability of the refrigerant used in the air conditioner 900. For example, the air conditioner 900 slows the switching speed of the digital gate driver module included in the power conversion device 1 the more flammable the refrigerant used in the air conditioner 900 is. By slowing the switching speed of the digital gate driver module, the air conditioner 900 can reduce surge voltage and prevent discharge caused by electromagnetic noise, thereby preventing refrigerant from burning even if it leaks from the air conditioner 900.

[0097] Refrigerants used in the air conditioner 900 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 may be combined with other known technologies, or different embodiments may be combined with each other. It is also possible to omit or modify parts of the configurations as long as they do not deviate from the gist of the invention.

[0099] 1 Power conversion device, 2,900 Air conditioner, 11 Model deviation calculation unit, 12 Current estimator, 13 Subtractor, 14 Deviation calculation unit, 21 First angular velocity estimation unit, 22 Second angular velocity estimation unit, 23 Adder, 30 Short circuit unit, 31 Diode bridge, 32 Short circuit element, 101 Speed ​​estimation device, 110, 110a Commercial power supply, 130 Converter, 131 to 134, 131a to 134a, 131b, 131c Rectifying element, 135, 135a to 135c Reactor, 136, 136a to 136d, 311a to 311f Switching element, 137, 137a to 137d, 312a to 312f Freewheeling diode, 138 Diode, 140, 340 Waveform shape change 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 operation 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 air conditioning, One or more switching elements included in at least one of the one or more power converters that perform power conversion; a waveform shape changing unit capable of changing a waveform shape of a switching waveform of the switching element without physically switching a gate resistor; an operating state detection unit that detects an operating state of the air conditioner; 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 in accordance with the operating state; An air conditioner equipped with:

2. An air conditioner that performs air conditioning control, One or more switching elements included in at least one of the one or more power converters that perform power conversion; a plurality of transistors mounted for driving the switching element; and a waveform shape changing unit capable of changing a waveform shape of a switching waveform of the switching element by changing the number of the plurality of transistors to be operated; an operating state detection unit that detects an operating state of the air conditioner; 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 in accordance with the operating state; An air conditioner equipped with:

3. the waveform shape changing unit divides at least one of a turn-on period and a turn-off period of the switching element into two or more periods based on the control signal output from the waveform shape control signal output unit, and changes the amplitude of a gate current or a gate voltage for the switching element to a different magnitude in each divided period, thereby changing noise and loss generated in the switching element in accordance with the operating state.

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

4. The waveform shape changing unit changes a waveform shape of the switching waveform of the switching element while at least one of a compressor motor and a fan motor included in the air conditioner is rotating.

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

5. the waveform shape control signal output unit changes a waveform shape of the switching waveform of the switching element so as to suppress the loss when the operating state is a light load operation that is less than a specified load, and changes a waveform shape of the switching waveform of the switching element so as to suppress the noise when the operating state is a heavy load operation that is equal to or greater than a specified load. The air conditioner according to claim 3.

6. When the operating state is an intermediate cooling condition or an intermediate heating condition, the light load operation is performed, and when the operating state is a rated cooling condition, a rated heating condition, or other air temperature condition, the heavy load operation is performed. The air conditioner according to claim 5.

7. When the difference between the outside air temperature and the set temperature of the air conditioner is less than a specified threshold, the air conditioner is in the light load operation, and when the difference between the outside air temperature and the set temperature of the air conditioner is equal to or greater than a specified threshold, the air conditioner is in the heavy load operation. The air conditioner according to claim 5.

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

9. When at least one of the input current and the input power input to the power converter is less than a specified threshold, the power converter is in the light load operation, and when at least one of the input current and the input power input to the power converter is equal to or greater than a specified threshold, the power converter is in the heavy load operation. 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.

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