Power conversion device, motor drive device, and equipment for refrigeration cycle applications

Abstract

A power conversion device (1) comprises: a converter (130) which includes a reactor (135) and one or more switching elements and which rectifies a first AC voltage outputted from an AC power source (110) to convert the AC voltage to a first DC voltage while also boosting the voltage; a capacitor (210) that smoothes the first DC voltage to a second DC voltage; and an inverter (310) that converts the second DC voltage to a second AC voltage of a desired amplitude and phase, and outputs the second AC voltage to a motor (314), wherein the converter (130) is a single-stage boost AC-DC converter, a totem pole AC-DC converter, a semi-bridgeless AC-DC converter, or a full-bridgeless AC-DC converter, the reactor (135) and the capacitor (210) are mounted on the same printed wiring board, and a shield is placed between the reactor (135) and the capacitor (210).

Description

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

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

[0002] Conventionally, there are power conversion devices that rectify AC voltage supplied from an AC power source such as a commercial power source and boost it to a desired voltage. For example, Patent Document 1 discloses a technology for a power factor correction circuit that uses a single-transistor boost AC (Alternating Current)-DC (Direct Current) converter, i.e., a single-transistor boost AC-DC converter, to boost the DC voltage after rectifying the AC voltage. In a circuit configuration such as the single-transistor boost AC-DC converter described in Patent Document 1, by increasing the carrier frequency of the switching of the switching element included in the single-transistor boost AC-DC converter, the capacity of the reactor included in the single-transistor boost AC-DC converter can be reduced, thereby reducing the dimensions, mass, etc. of the single-transistor boost AC-DC converter. As a result, when mounting the circuit components of the single-transistor boost AC-DC converter on a printed wiring board, the reactor can also be mounted on the printed wiring board.

[0003] JP 2010-114993 A

[0004] Mounting the circuit components of a single-transistor boost AC-DC converter on a printed wiring board allows the heat-generating reactor and the smoothing capacitor located downstream of the single-transistor boost AC-DC converter to be mounted on the same printed wiring board. However, electrolytic capacitors are typically used as smoothing capacitors, and their lifespan shortens as temperatures rise. Therefore, if the reactor and smoothing capacitor are mounted on the same printed wiring board to reduce the dimensions and weight of a product that uses a single-transistor boost AC-DC converter, the heat generated by the reactor shortens the lifespan of the electrolytic capacitor, which is a problem.

[0005] The present disclosure has been made in view of the above, and has an object to provide a power conversion device that can reduce the effect on a capacitor of heat generated by a reactor used in a converter.

[0006] In order to solve the above-mentioned problems and achieve the object, the power conversion device according to the present disclosure includes a converter having a reactor and one or more switching elements, and rectifying and boosting a first AC voltage output from an AC power supply to convert it into a first DC voltage; a capacitor connected in parallel to the converter, and smoothing the first DC voltage into a second DC voltage; and an inverter connected in parallel to the capacitor, and converting the second DC voltage into a second AC voltage of a desired amplitude and phase to output it to a motor. The converter is a single-transistor boost AC / DC converter including a rectifier circuit composed of four rectifier elements and a boost circuit including one switching element, or a totem-pole AC / DC converter configured as a rectifier boost circuit having two legs each consisting of two semiconductor elements connected in series, with the semiconductor element of the first leg being a switching element and the semiconductor element of the second leg being a rectifier element, or a half-bridgeless AC / DC converter configured as a rectifier boost circuit, with the semiconductor elements of the upper arms of the first and second legs being rectifier elements and the semiconductor elements of the lower arms being switching elements, or a full-bridgeless AC / DC converter configured as a rectifier boost circuit, with all semiconductor elements being switching elements.The reactor and capacitor are mounted on the same printed wiring board, and a shield is placed between the reactor and the capacitor.

[0007] The power conversion device according to the present disclosure has an effect of being able to reduce the influence on the capacitor caused by heat generated by the reactor used in the converter.

[0008] FIG. 1 shows a configuration example of a power conversion device according to embodiment 1. FIG. 2 shows a configuration example of a power conversion device according to embodiment 1. FIG. 3 shows a configuration example of a power conversion device according to embodiment 1. FIG. 4 shows a configuration example of a power conversion device according to embodiment 1. FIG. 5 shows a shape of a reactor used in the power conversion device according to embodiment 1. FIG. 6 shows a shape of a capacitor used in the power conversion device according to embodiment 1. FIG. 7 shows an example of arrangement when a reactor and a capacitor are mounted on the same printed wiring board as a comparative example. FIG. 8 shows an example in which a shield is placed between the reactor and the capacitor when the reactor and the capacitor are mounted on the same printed wiring board in the power conversion device according to embodiment 1. Figure shows an example in which a motor connection wire is arranged as a shield between a reactor and a capacitor when the reactor and a capacitor are mounted on the same printed wiring board in a power conversion device according to embodiment 1. Figure shows an example in which a heat sink and a motor connection wire are arranged as a shield between a reactor and a capacitor when the reactor and a capacitor are mounted on the same printed wiring board in a power conversion device according to embodiment 1. Figure shows an example of the arrangement of a reactor, a capacitor, and a shield on a printed wiring board in a power conversion device according to embodiment 1 as a comparative example. Figure 1 shows an example of the arrangement of a reactor in a power conversion device according to embodiment 2. Figure 2 shows an example of the arrangement of a reactor in a power conversion device according to embodiment 2. Figure 3 shows an example of the arrangement of a reactor in a power conversion device according to embodiment 2. Figure 4 shows an example of the configuration of a refrigeration cycle application device according to embodiment 3.

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

[0010] First Embodiment. FIG. 1 is a first diagram showing a configuration example of a power conversion device 1 according to a first embodiment. The power conversion device 1 is connected to an AC power supply 110 and a motor 314. The power conversion device 1 converts a first AC voltage, which is a power supply voltage Vs supplied from the AC power supply 110, such as a commercial power supply, into a second AC voltage having a desired amplitude and phase, and supplies the second AC voltage to the motor 314. In the example of FIG. 1, the AC power supply 110 is a single-phase AC power supply, but may be a three-phase AC power supply. The power conversion device 1 includes a converter 130, a capacitor 210, an inverter 310, current detection units 501 and 502, and a control unit 400. The power conversion device 1 and the motor 314 constitute a motor drive device 2.

[0011] Converter 130 is a power converter that converts an AC voltage, which is a power supply voltage Vs supplied from AC power supply 110, into a DC voltage. Converter 130 includes rectifying elements 131 to 134, a reactor 135, a switching element 136, a freewheeling diode 137, and a diode 138. Converter 130 has a bridge circuit formed by rectifying elements 131 to 134, rectifies a first AC voltage, which is a power supply voltage Vs supplied from AC power supply 110, and boosts and outputs the rectified DC voltage. In the following description, the rectified and boosted DC voltage, i.e., the DC voltage output to capacitor 210, may be referred to as a first DC voltage. The switching element 136 is, 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.

[0012] In the example of FIG. 1 , the converter 130 includes a rectifier circuit 161, which is a bridge circuit configured with rectifier elements 131 to 134 such as diodes, and a boost circuit 162 configured with a reactor 135, a switching element 136, a freewheeling diode 137, and a diode 138. However, the configuration of the converter 130 is not limited to the example of FIG. 1 . FIG. 2 is a second diagram showing a configuration example of the power conversion device 1 according to the first embodiment. FIG. 3 is a third diagram showing a configuration example of the power conversion device 1 according to the first embodiment. FIG. 4 is a fourth diagram showing a configuration example of the power conversion device 1 according to the first embodiment. As shown in FIG. 2 , the converter 130 may be configured with a reactor 135, switching elements 131a and 132a, freewheeling diodes 131b and 132b, and rectifier elements 133 and 134. The converter 130 may also be composed of a reactor 135, rectifying elements 131 and 133, switching elements 132a and 134a, and freewheeling diodes 132b and 134b, as shown in Fig. 3. The converter 130 may also be composed of a reactor 135, switching elements 131a to 134a, and freewheeling diodes 131b to 134b, as shown in Fig. 4.

[0013] In this way, converter 130 is a single-transistor step-up AC / DC converter including rectifier circuit 161 configured with four rectifier elements 131 to 134 and step-up circuit 162 including one switching element 136, or a totem-pole AC / DC converter configured as a rectifier step-up circuit having two legs each having two semiconductor elements connected in series, with the semiconductor elements of the first leg being switching elements 131 a and 132 a and the semiconductor elements of the second leg being rectifier elements 133 and 134, or a half-bridgeless AC / DC converter configured as a rectifier step-up circuit, with the semiconductor elements of the upper arms in the first leg and the second leg being switching elements 132 a and 134 a, or a full-bridgeless AC / DC converter configured as a rectifier step-up circuit and all of the semiconductor elements being switching elements 131 a to 134 a. That is, converter 130 may have any configuration as long as it has reactor 135 and one or more switching elements, and rectifies and boosts the first AC voltage output from AC power supply 110 to convert it into a first DC voltage. In the following, the power conversion device 1 shown in FIG. 1 will be described as an example.

[0014] The capacitor 210 is connected in parallel to the output terminal of the converter 130 and smoothes the first DC voltage into a second DC voltage. The capacitor 210 is, for example, an electrolytic capacitor.

[0015] The inverter 310 is a power converter connected in parallel across the capacitor 210. The inverter 310 has six switching elements 311 and six freewheeling diodes 312. The inverter 310 turns the switching elements 311 on and off under the control of the control unit 400, converts the DC voltage output from the converter 130 and the capacitor 210 into a second AC voltage having a desired amplitude and phase, i.e., generates a second AC voltage, and outputs it to the motor 314. In other words, the inverter 310 converts the second DC voltage into a second AC voltage and outputs it. The switching elements 311 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.

[0016] The current detection unit 501 detects the current flowing through the converter 130. The current detection unit 501 can detect the current flowing at the installation position using a current detection resistor or the like, but the configuration of the current detection unit 501 is not limited to this. The current detection unit 501 outputs the detection result to the control unit 400. The current detection unit 502 detects the current flowing through the motor 314. The current detection unit 502 can detect the current flowing at the installation position using a current detection resistor or the like, but the configuration of the current detection unit 502 is not limited to this. The current detection unit 502 outputs the detection result to the control unit 400. Note that the power conversion device 1 may be provided with a current detection unit that detects the current flowing at a position other than the position shown in FIG. 1 , or may be provided with a voltage detection unit that detects the voltage in a specific section.

[0017] Control unit 400 controls the on / off of switching element 136 included in converter 130 and six switching elements 311 included in inverter 310 based on the detection results of current detection units 501 and 502, etc. Although not shown in the example of FIG. 1 , control unit 400 may also control the on / off of switching element 136 included in converter 130 and six switching elements 311 included in inverter 310 using the detection results of a voltage detection unit that detects the voltage across capacitor 210, i.e., the DC bus voltage Vdc, which is the second DC voltage. In this embodiment, the operation of control unit 400 to control converter 130 and inverter 310 is a typical operation, so detailed description thereof will be omitted.

[0018] 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 voltage supplied from the inverter 310 to perform a compression operation. For example, when the compressor is a hermetic compressor, the load torque of the motor 314 that drives the compressor can often be considered a constant torque load. The motor 314 may have a Y-connection or a Δ-connection, or may have a motor winding (not shown) that is switchable between the Y-connection and the Δ-connection. Furthermore, the load connected to the power conversion device 1, i.e., the inverter 310, is not limited to the compressor-driving motor 314, but may also be a fan motor or the like.

[0019] Next, circuit components used in the power conversion device 1 will be described. Circuit components such as the reactor 135 and capacitor 210 used in the power conversion device 1 of the present embodiment are generally larger in size than other circuit components. FIG. 5 is a diagram illustrating the shape of the reactor 135 used in the power conversion device 1 according to the first embodiment. As shown in FIG. 5, the reactor 135 is a toroidal coil having a circular ring shape. In FIG. 5, the reactor 135 on the left side is viewed from a direction in which the central hole formed by the circular ring shape is visible, and the reactor 135 on the right side is viewed from a direction rotated 90 degrees around the vertical axis of the left reactor 135. The reactor 135 shown in FIG. 5 varies in size depending on the capacity, but here, it is assumed to be sized so that it can be mounted on a typical printed wiring board. FIG. 6 is a diagram illustrating the shape of the capacitor 210 used in the power conversion device 1 according to the first embodiment. As described above, the capacitor 210 is, for example, an electrolytic capacitor, and therefore has a cylindrical shape. The capacitor 210 shown in FIG. 6 also varies in size depending on the capacitance, similar to the capacitor 210, but here it is assumed to be of a size that can be mounted on a general printed wiring board.

[0020] FIG. 7 is a diagram showing an example of a comparative example in which the reactor 135 and the capacitor 210 are mounted on the same printed wiring board 450. FIG. 7 is a diagram showing the printed wiring board 450 as viewed from above. For simplicity's sake, the example in FIG. 7 shows only the reactor 135 and the capacitor 210 mounted on the printed wiring board 450. However, in actuality, other circuit components are also mounted on the printed wiring board 450. The same applies to subsequent diagrams of the printed wiring board 450. Because the reactor 135 is a toroidal coil with a circular ring shape as shown in FIG. 5 , the wiring is concentrated on the inside of the ring, and the inside of the ring generates the most heat. As a result, heat is transferred from the center of the ring of the reactor 135 to the periphery, causing the temperature of the periphery to rise. If the capacitor 210 is mounted around the reactor 135 as in the example in FIG. 7 , the temperature of the capacitor 210 may rise due to the heat from the reactor 135, potentially shortening its lifespan. 7, dotted arrows indicate heat transferred from the center of the ring of reactor 135 to the periphery. In the drawings of printed wiring board 450 shown below, the dotted arrows may be omitted, but it is assumed that heat is transferred from the center of the ring of reactor 135 to the periphery, just like in FIG.

[0021] Therefore, in the present embodiment, the power conversion device 1 is configured such that, when the reactor 135 and the capacitor 210 are mounted on the same printed wiring board 450, a shield is disposed between the reactor 135 and the capacitor 210. FIG. 8 is a diagram showing an example in which a shield 460 is disposed between the reactor 135 and the capacitor 210 when the reactor 135 and the capacitor 210 are mounted on the same printed wiring board 450 in the power conversion device 1 according to the first embodiment. FIG. 8 is a diagram showing the printed wiring board 450 as viewed from above. By disposing the shield 460 between the reactor 135 and the capacitor 210 on the printed wiring board 450, the capacitor 210 can be reduced in influence of heat from the reactor 135. In the power conversion device 1, because the shield 460 is disposed between the reactor 135 and the capacitor 210, heat from the reactor 135 is less likely to be transmitted to the capacitor 210, and a temperature rise in the capacitor 210 is suppressed, thereby preventing a decrease in the lifespan of the capacitor 210. Specifically, the shield 460 includes a heat sink for cooling the switching element 136, a motor connection wire for connecting the inverter 310 and the motor 314, and the like.

[0022] FIG. 9 is a diagram illustrating an example in which a heat sink 461 is disposed as a shield 460 between the reactor 135 and the capacitor 210 when the reactor 135 and the capacitor 210 are mounted on the same printed wiring board 450 in the power conversion device 1 according to the first embodiment. FIG. 9 is a diagram illustrating the printed wiring board 450 as viewed from above. The heat sink 461 is intended to be used for cooling the switching element 136 and the freewheeling diode 137, but may also be used for cooling the rectifying elements 131 to 134, the freewheeling diode 137, and the six switching elements 311 included in the inverter 310 shown in FIG. 1. In the power conversion device 1, the heat sink 461 is disposed as a shield 460 between the reactor 135 and the capacitor 210. This makes it difficult for heat from the reactor 135 to be transferred to the capacitor 210, suppressing a temperature rise in the capacitor 210 and thereby preventing a decrease in the life of the capacitor 210.

[0023] 2, the heat sink 461 may be used to cool the six switching elements 311 included in the inverter 310, together with the switching elements 131a and 132a and the rectifying elements 133 and 134. In the example of Fig. 3, the heat sink 461 may be used to cool the six switching elements 311 included in the inverter 310, together with the rectifying elements 131 and 133 and the switching elements 132a and 134a. In the example of Fig. 4, the heat sink 461 may be used to cool the six switching elements 311 included in the inverter 310, together with the switching elements 131a to 134a.

[0024] 10 is a diagram showing an example in which a motor connecting wire 462 is arranged as a shield 460 between the reactor 135 and the capacitor 210 when the reactor 135 and the capacitor 210 are mounted on the same printed wiring board 450 in the power conversion device 1 according to the first embodiment. FIG. 10 is a diagram showing the printed wiring board 450 as viewed from above. The motor connecting wire 462 is a wire that connects the inverter 310 and the motor 314. In the power conversion device 1, the motor connecting wire 462 is arranged as the shield 460 between the reactor 135 and the capacitor 210, making it difficult for heat from the reactor 135 to be transmitted to the capacitor 210, suppressing a temperature rise in the capacitor 210 and preventing a decrease in the life of the capacitor 210.

[0025] FIG. 11 is a diagram illustrating an example in which a heat sink 461 and a motor connecting wire 462 are arranged as a shield 460 between the reactor 135 and the capacitor 210 when the reactor 135 and the capacitor 210 are mounted on the same printed wiring board 450 in the power conversion device 1 according to the first embodiment. FIG. 11 is a diagram illustrating the printed wiring board 450 as viewed from above. The heat sink 461 is the same as the heat sink 461 illustrated in FIG. 9 , and the motor connecting wire 462 is the same as the motor connecting wire 462 illustrated in FIG. 10 . In the power conversion device 1, the heat sink 461 and the motor connecting wire 462 are arranged as the shield 460 between the reactor 135 and the capacitor 210. This makes it difficult for heat from the reactor 135 to be transferred to the capacitor 210, suppressing a temperature rise in the capacitor 210 and preventing a decrease in the life of the capacitor 210. Furthermore, in the example of Figure 11, the power conversion device 1 can increase the distance between the reactor 135 and the capacitor 210 compared to the examples of Figures 9 and 10, which makes it more difficult for heat from the reactor 135 to be transferred to the capacitor 210 and suppresses the temperature rise of the capacitor 210, thereby preventing a decrease in the lifespan of the capacitor 210.

[0026] As described above, according to the present embodiment, in power conversion device 1, when reactor 135 and smoothing capacitor 210 of converter 130 are mounted on the same printed wiring board 450, shield 460 is arranged between reactor 135 and capacitor 210. Shield 460 may be heat sink 461, motor connecting wire 462, or both heat sink 461 and motor connecting wire 462. This allows power conversion device 1 to reduce the effect on capacitor 210 of heat generated by reactor 135 used in converter 130.

[0027] In the present embodiment, the shield 460 disposed between the reactor 135 and the capacitor 210 is the heat sink 461, or the motor connecting wire 462, or the heat sink 461 and the motor connecting wire 462, but is not limited to this. Other configurations of the shield 460 may be used as long as they can suppress the influence of heat from the reactor 135 on the capacitor 210.

[0028] Second Embodiment In a second embodiment, when the reactor 135 is mounted on the printed wiring board 450 in the power conversion device 1, the orientation of the reactor 135 is set to be different from the orientation of the reactor 135 in the first embodiment.

[0029] FIG. 12 is a diagram illustrating an example of the arrangement of the reactor 135, the capacitor 210, and the shield 460 on the printed wiring board 450 in the power conversion device 1 according to the first embodiment as a comparative example. FIG. 12 is a side view of the state of FIG. 8 in which the reactor 135, the capacitor 210, and the shield 460 are arranged on the printed wiring board 450. As described above, the reactor 135 is a toroidal coil having a circular ring shape. Since the wiring is concentrated on the inside of the ring, the inside of the ring generates the most heat. As a result, heat is transferred from the center of the ring of the reactor 135 to the periphery, causing the temperature of the periphery to rise. As shown in FIG. 12, the shield 460 can suppress the thermal influence from the reactor 135 to the capacitor 210, but the temperature of the shield 460 may rise due to the influence of heat from the reactor 135. If the temperature of the shield 460 increases due to the effect of heat from the reactor 135 , there is a possibility that the temperature of the capacitor 210 will increase due to the effect of heat from the shield 460 .

[0030] FIG. 13 is a first diagram showing an example of the arrangement of the reactor 135 in the power conversion device 1 according to the second embodiment. FIG. 14 is a second diagram showing an example of the arrangement of the reactor 135 in the power conversion device 1 according to the second embodiment. The orientations of FIGS. 13 and 14 correspond to the orientations of FIGS. 8 and 12, respectively. In the second embodiment, as shown in FIGS. 13 and 14, the reactor 135 is arranged so that the direction of the hole formed in the center by the annular shape is perpendicular to the surface of the printed wiring board 450. This allows the power conversion device 1 to suppress the influence of heat from the center of the annular shape of the reactor 135 on the shield 460.

[0031] FIG. 15 is a third diagram illustrating an example of the arrangement of the reactor 135 in the power conversion device 1 according to the second embodiment. FIG. 15 illustrates a side view of the printed wiring board 450. A top view of the printed wiring board 450 illustrated in FIG. 15 is omitted. As illustrated in FIG. 15 , the reactor 135 is arranged so that the direction of the hole in the center formed by the annular shape is oblique to the surface of the printed wiring board 450. Even in this case, the power conversion device 1 can suppress the influence of heat from the center of the annular shape of the reactor 135 on the shield 460. The reactor 135 is arranged such that, assuming that the annular portion of the reactor 135 illustrated in FIG. 14 is horizontal, i.e., parallel, to the printed wiring board 450, the angle between the annular portion of the reactor 135 and the printed wiring board 450 is less than 90 degrees. Even in this case, the power conversion device 1 can suppress the influence of heat from the center of the annular shape of the reactor 135 on the shield 460.

[0032] As described above, according to the present embodiment, in the power conversion device 1, when the reactor 135 is arranged on the printed wiring board 450, the annular portion of the reactor 135 is oriented in such a way that heat is not directly transferred from the center of the annular portion of the reactor 135 to the shield 460. As a result, the power conversion device 1 can further reduce the effect of heat generated by the reactor 135 used in the converter 130 on the capacitor 210, compared to the first embodiment.

[0033] Third Embodiment Fig. 16 is a diagram showing a configuration example of a refrigeration cycle-applied apparatus 900 according to a third embodiment. The refrigeration cycle-applied apparatus 900 according to the third embodiment includes the power conversion device 1 described in the first embodiment. The refrigeration cycle-applied apparatus 900 according to the third embodiment may also include the power conversion device 1 shown in Figs. 2 to 4. The refrigeration cycle-applied apparatus 900 according to the third embodiment may be applied to products equipped with a refrigeration cycle, such as air conditioners, refrigerators, freezers, and heat pump water heaters. In Fig. 16, components having the same functions as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

[0034] The refrigeration cycle application equipment 900 includes a compressor 315 incorporating the motor 314 in embodiment 1, a four-way valve 902, an indoor heat exchanger 906, an expansion valve 908, and an outdoor heat exchanger 910, which are attached via refrigerant piping 912.

[0035] Inside the compressor 315, a compression mechanism 904 that compresses the refrigerant and a motor 314 that operates the compression mechanism 904 are provided.

[0036] The refrigeration cycle device 900 can perform heating or cooling operation by switching the four-way valve 902. The compression mechanism 904 is driven by a motor 314 that is variably controlled in speed.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 1 Power conversion device, 2 Motor drive device, 110 AC power source, 130 Converter, 131 to 134 Rectifier elements, 131a to 134a, 136, 311 Switching elements, 135 Reactor, 131b to 134b, 137, 312 Freewheeling diode, 138 Diode, 161 Rectifier circuit, 162 Boost circuit, 210 Capacitor, 310 Inverter, 314 Motor, 315 Compressor, 400 Control unit, 450 Printed wiring board, 460 Shield, 461 Heat sink, 462 Motor connection wiring, 501, 502 Current detection unit, 900 Refrigeration cycle applied equipment, 902 Four-way valve, 904 Compression mechanism, 906 Indoor heat exchanger, 908 Expansion valve, 910 Outdoor heat exchanger, 912 Refrigerant piping.

Claims

1. A power conversion device comprising a reactor and one or more switching elements, a converter that rectifies and boosts a first AC voltage output from an AC power supply and converts it into a first DC voltage, a capacitor connected in parallel with the converter that smoothes the first DC voltage into a second DC voltage, and an inverter connected in parallel with the capacitor that converts the second DC voltage into a second AC voltage having a desired amplitude and phase and outputs it to a motor, wherein the converter is a single-stage boost type AC-DC converter including a rectifier circuit composed of four rectifier elements and a boost circuit including one of the switching elements, or a rectifier boost circuit configuration having two legs in which two semiconductor elements are connected in series, wherein the semiconductor element of the first leg is the switching element and the semiconductor element of the second leg is composed of a rectifier element, a totem pole type AC-DC converter, or a rectifier boost circuit configuration in which the semiconductor elements of the upper arms in the first leg and the second leg are rectifier elements and the semiconductor elements of the lower arms are the switching elements, a half-bridge-less AC-DC converter, or a rectifier boost circuit configuration in which all the semiconductor elements are the switching elements, a full-bridge-less AC-DC converter, and wherein the reactor and the capacitor are mounted on the same printed wiring board, and a shield is disposed between the reactor and the capacitor.

2. The power conversion device according to claim 1, wherein the shield is a heat sink for cooling the switching element.

3. The power conversion device according to claim 1 or 2, wherein the shield is a motor connection wiring for connecting the inverter and the motor.

4. The power conversion device according to claim 2 or 3, wherein the reactor is an annular toroidal coil, and is arranged such that the direction of the hole at the center formed by the annular shape is perpendicular to the surface of the printed wiring board.

5. The power conversion device according to claim 2 or 3, wherein the reactor is an annular toroidal coil, and is arranged such that the direction of the hole at the center formed by the annular shape is oblique to the surface of the printed wiring board.

6. A motor drive device comprising the power conversion device according to any one of claims 1 to 5.

7. A refrigeration cycle application device comprising the power conversion device according to any one of claims 1 to 5.

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