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

Abstract

This power conversion device (1) comprises: a converter (130) which includes a reactor (135), rectifying diodes (131 to 134), a switching element (136), and a booster diode (138), and which rectifies an AC voltage applied from an AC power source (110) while also boosting the DC voltage after rectification and outputting the boosted DC voltage; and an inverter (310) that converts the DC voltage outputted from the converter (130) to an AC voltage of a desired amplitude and phase and that outputs the converted AC voltage to a motor (314). A rectifier circuit section module (252) accommodating the reactor (135) and rectifying diodes (131 to 134) is mounted on the same board as a booster section switch module (254) accommodating the switching element (136). When the converter (130) is in operation, the temperature of the rectifying diodes (131 to 134) is higher than a temperature calculated from the thermal resistance of the rectifying diodes (131 to 134).

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] Patent Document 1 listed below discloses a power conversion device intended for use in an air conditioning system, which includes a power conversion unit having a substrate on which wide-gap semiconductor elements and rectifying diodes are mounted, and a thermoelectric power generation module for converting heat from the power conversion unit into electricity and recovering the electricity, with the rectifying diodes and wide-gap semiconductor elements being arranged on different substrates.

[0003] The technology of Patent Document 1 is characterized by arranging a wide-gap semiconductor element and a rectifier diode, which has a lower heat resistance temperature than the wide-gap semiconductor element, on different substrates. This configuration prevents the heat from the wide-gap semiconductor element from adversely affecting the rectifier diode, which is a low-heat-resistant component, while effectively recovering the heat of the power conversion unit as electric power, thereby improving the operating efficiency of the power conversion device.

[0004] JP 2008-61374 A

[0005] However, the technology of Patent Document 1 requires a thermoelectric power generation module, which has the drawback of increasing the device size and cost. Furthermore, placing the wide-gap semiconductor element and the rectifier diode on different substrates leads to an increase in the number of components. Therefore, a different method is desired for improving the operating efficiency of a power conversion device while suppressing increases in device size, cost, and number of components.

[0006] The present disclosure has been made in view of the above, and aims to provide a power conversion device that can improve operating efficiency while suppressing increases in device size, cost, and number of parts.

[0007] In order to solve the above-mentioned problems and achieve the object, a power conversion device according to the present disclosure includes a converter and an inverter connected in parallel to the converter, which converts a DC voltage output by the converter into an AC voltage of a desired amplitude and phase and outputs the AC voltage to a motor. The converter has a reactor, a first module accommodating a rectifying diode for rectifying an AC voltage applied from an AC power source, and a second module accommodating one or more first switching elements for boosting the rectified voltage output from the first module. The reactor, the first module, and the second module are mounted on the same substrate. During operation of the converter, the temperature of the rectifying diode becomes higher than a temperature calculated from the thermal resistance of the rectifying diode.

[0008] The power conversion device according to the present disclosure has the advantage of being able to improve operating efficiency while suppressing increases in device size, cost, and number of parts.

[0009] FIG. 1 is a diagram showing a first configuration example of a power conversion device according to embodiment 1; FIG. 2 is a diagram showing a second configuration example of a power conversion device according to embodiment 1; FIG. 3 is a diagram showing a third configuration example of a power conversion device according to embodiment 1; FIG. 4 is a diagram showing a fourth configuration example of a power conversion device according to embodiment 1; FIG. 5 is a diagram showing a fifth configuration example of a power conversion device according to embodiment 1; FIG. 6 is a diagram used to explain the main points of the configuration of a power conversion device according to embodiment 1; FIG. 7 is a diagram used to explain the forward characteristics of a rectifier diode used in a power conversion device according to embodiment 1; FIG. 8 is a diagram showing an example of a derating curve used in a power conversion device according to embodiment 1; FIG. 9 is a diagram used to explain the main points of the configuration of a power conversion device according to embodiment 2;

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 below with reference to the accompanying drawings.

[0011] First Embodiment Fig. 1 is a diagram showing a first 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 an AC voltage, which is a power supply voltage applied from the AC power supply 110, into an AC voltage having a desired amplitude and phase and outputs the 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 it may also 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 form a motor drive device 2.

[0012] The converter 130 is a power converter that converts the AC voltage applied from the AC power supply 110 into a DC voltage. The converter 130 includes rectifier diodes 131 to 134, a reactor 135, a switching element 136, a freewheeling diode 137, and a boost diode 138. The converter 130 has a bridge circuit formed by the rectifier diodes 131 to 134, and rectifies the AC voltage applied from the AC power supply 110, while boosting and outputting the rectified DC voltage. In this document, the switching element 136 may be referred to as a "first switching element."

[0013] The switching element 136 is, for example, but not limited to, an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET), a bipolar transistor, etc. When the switching element 136 is a MOSFET, the free wheel diode 137 can be omitted by using a parasitic diode formed inside the MOSFET.

[0014] The boost circuit 162 of the configuration shown in FIG. 1 performs boost operation using a combination of one reactor 135, one switching element 136, and one boost diode 138. The boost circuit 162 configured in this manner is referred to as a "single-transistor boost circuit." The converter 130 shown in FIG. 1 is also referred to as a "single-transistor boost AC / DC converter." While FIG. 1 shows an example in which the boost circuit 162 is configured as a single-stage single-transistor boost circuit, the present invention is not limited to this example. Although not shown, the boost circuit 162 may be configured as a multi-stage circuit by including multiple single-transistor boost circuits.

[0015] Furthermore, in the example of FIG. 1 , the converter 130 includes a rectifier circuit 161, which is a bridge circuit configured with rectifier diodes 131 to 134 such as diodes, and a boost circuit 162 configured with a reactor 135, a switching element 136, a freewheel diode 137, and a boost diode 138. However, the configuration of the converter 130 is not limited to the example of FIG. 1 . For example, the converter 130 may be configured as shown in FIGS. 2 to 5 . FIG. 2 is a diagram illustrating a second configuration example of the power conversion device 1 according to the first embodiment. FIG. 3 is a diagram illustrating a third configuration example of the power conversion device 1 according to the first embodiment. FIG. 4 is a diagram illustrating a fourth configuration example of the power conversion device 1 according to the first embodiment. FIG. 5 is a diagram illustrating a fifth configuration example of the power conversion device 1 according to the first embodiment.

[0016] In the converter 130, the reactor 135 provided in the boost circuit 162 is disposed between the rectifier circuit 161 and the boost diode 138 in the configuration of FIG. 1, but may be disposed between the AC power supply 110 and the rectifier circuit 161 as shown in FIG. 2.

[0017] 3, the converter 130 may be configured with a reactor 135, switching elements 131a and 132a, freewheeling diodes 131b and 132b, and rectifier diodes 133 and 134. The converter 130 shown in FIG. 3 is configured as a rectifier boost circuit having two legs, each of which has two semiconductor elements connected in series, with the semiconductor elements of the first leg being the switching elements 131a and 132a, and the semiconductor elements of the second leg being the rectifier diodes 133 and 134. The converter 130 configured in this manner is called a "totem-pole AC-DC converter," for example.

[0018] 2, the switching element 136, the freewheeling diode 137, and the boost diode 138 constituting the boost circuit 162 may each include two switching elements 136a and 136b, two freewheeling diodes 137a and 137b, and two boost diodes 138a and 138b, as shown in FIG. 4. The switching element 136a, the freewheeling diode 137a, and the boost diode 138a constitute a first boost circuit, and the switching element 136b, the freewheeling diode 137b, and the boost diode 138b constitute a second boost circuit. The first and second boost circuits operate alternately with a phase difference of 180 degrees. A converter 130 having a boost circuit 162 with such a configuration is called an "interleaved converter," for example.

[0019] 5, a rectifier circuit 161 may be configured by the rectifier diodes 131 and 132, and a boost circuit 162 may be configured by the reactor 135, switching elements 136a to 136d, freewheeling diodes 137a to 137d, and capacitor 139. In the rectifier circuit 161, the connection point of the rectifier diodes 131 and 132 is connected to one end of the AC power supply 110 via the reactor 135. In the boost circuit 162, freewheeling diodes 137a to 137d are connected in parallel to the switching elements 136a to 136d, respectively. In the boost circuit 162, the capacitor 139 is connected between the connection point of the switching elements 136a and 136b and the connection point of the switching elements 136c and 136d, and the connection point of the switching elements 136b and 136c is connected to the other end of the AC power supply 110. Converter 130 configured in this way is called a "multi-level converter" or the like.

[0020] As described above, converter 130 in the first embodiment may have reactor 135, one or more diodes, and one or more first switching elements, and may be configured to rectify and boost the AC voltage applied from AC power supply 110 to convert it into a DC voltage. Hereinafter, the power conversion device 1 shown in FIG. 1 will be described as an example.

[0021] Capacitor 210 is connected in parallel to the output terminal of converter 130, and smoothes the DC voltage applied from converter 130. Capacitor 210 is, for example, an electrolytic capacitor.

[0022] 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 an AC voltage having a desired amplitude and phase, and outputs the AC voltage to the motor 314. The switching elements 311 may be, for example, an IGBT, a MOSFET, a bipolar transistor, or the like, but are not limited to these. The circuit configuration of the inverter 310 may be any configuration, such as a full-bridge circuit, a single-phase bridge circuit, or a half-bridge circuit. In this document, the switching elements 311 may be referred to as a "second switching element."

[0023] 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.

[0024] The control unit 400 controls the on / off of the switching element 136 included in the converter 130 and the six switching elements 311 included in the inverter 310 based on the detection results of the current detection units 501 and 502, etc. Although not shown in the example of FIG. 1 , the control unit 400 may also control the on / off of the switching element 136 included in the converter 130 and the six switching elements 311 included in the inverter 310 using the detection results from a voltage detection unit that detects the DC bus voltage, which is the voltage across the capacitor 210. In the first embodiment, the operation of the control unit 400 to control the converter 130 and the inverter 310 is a general operation, and therefore a detailed description thereof will be omitted.

[0025] The motor 314 is a load connected to the power conversion device 1 and is connected to the inverter 310. 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 AC voltage applied 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 with respect to the motor windings (not shown), or may be configured to be switchable between the Y-connection and the Δ-connection. Furthermore, the load connected to the inverter 310 is not limited to the motor 314 for driving a compressor, but may also be a fan motor or the like.

[0026] Next, a description will be given of the configuration and operation of the power conversion device 1 according to embodiment 1. Fig. 6 is a diagram illustrating the configuration of the power conversion device 1 according to embodiment 1. Fig. 6 shows an example of how the circuit components of the converter 130 in the power conversion device 1 are mounted on the substrate 250.

[0027] 6 is a plan view, and the solid-line rectangular frame indicates the approximate mounting area of ​​the main circuit components. As shown in the figure, a rectifier circuit module 252, a booster switch module 254, a booster diode module 256, and an inverter module 258 are mounted on a first main surface 251a of the substrate 250. Although not shown in FIG. 6, a base portion of a cooler (not shown) is present below the portion where the rectifier circuit module 252, the booster switch module 254, the booster diode module 256, and the inverter module 258 are mounted, and the substrate 250 and the base portion of the cooler are in thermal contact.

[0028] The rectifier circuit module 252 houses the rectifier diodes 131 to 134 shown in Fig. 1, and the booster switch module 254 houses the switching element 136 and the freewheel diode 137 shown in Fig. 1. The booster diode module 256 houses the booster diode 138 shown in Fig. 1, and the inverter module 258 houses the switching element 311 and the freewheel diode 312 shown in Fig. 1. In this document, the rectifier circuit module 252, the booster switch module 254, the booster diode module 256, and the inverter module 258 may be referred to as the "first module," the "second module," the "third module," and the "fourth module," respectively.

[0029] FIG. 7 is a diagram illustrating the forward characteristics of the rectifier diodes 131 to 134 used in the power conversion device 1 according to the first embodiment. FIG. 7 shows an example of the forward characteristics of the rectifier diodes 131 to 134 used in the power conversion device 1 according to the first embodiment. The solid line is a characteristic curve when the element temperature Tc, which is the temperature of the rectifier diode, is 25°C, and the dashed line is a characteristic curve when the element temperature Tc is 150°C. The horizontal axis represents the forward voltage Vf, and the vertical axis represents the forward current If. As shown in FIG. 7, the rectifier diodes have a negative temperature characteristic in which the forward voltage Vf decreases as the element temperature Tc increases, regardless of the forward current If. In the first embodiment, this characteristic is utilized to improve the operating efficiency of the power conversion device 1.

[0030] When the power conversion device 1 operates, the switching element 136 and the boost diode 138 of the boost circuit 162, and the switching element 311 and the freewheel diode 312 of the inverter 310 are driven at high frequency. Therefore, in an operating state in which the same amount of current flows through the rectifier circuit 161, the boost circuit 162, and the inverter 310, the elements of the boost circuit 162 and the inverter 310, which are driven at high frequency, generate more heat than the elements of the rectifier circuit 161.

[0031] Here, as shown in FIG. 7 , the rectifier diodes 131 to 134 included in the rectifier circuit 161 have a forward voltage Vf with a negative temperature characteristic. Therefore, the higher the temperature of the rectifier diodes 131 to 134, the more the loss generated in the rectifier diodes 131 to 134 is reduced. Therefore, in the first embodiment, as shown in FIG. 6 , the booster switch module 254, the booster diode module 256, and the inverter module 258, which generate more heat than the booster diode module 256, are arranged around the rectifier circuit module 252 that houses the rectifier diodes 131 to 134. By arranging the rectifier circuit module 252 in this manner, the rectifier circuit module 252 receives heat from the booster switch module 254, the booster diode module 256, and the inverter module 258 arranged around it, as well as heat during operation via the base of the cooler and the substrate 250 with which it is in thermal contact. Therefore, the temperature rise is larger than when the rectifier circuit module 252 generates heat by itself alone, and it is possible to reduce loss by utilizing its own negative temperature characteristic.

[0032] In the power conversion device described in Patent Document 1, the wide-gap semiconductor elements and the rectifier diodes are arranged on different substrates, allowing for individual thermal design of the semiconductor element modules mounting these semiconductor elements. In contrast, in the power conversion device 1 according to the first embodiment, as described above, the rectifier circuit module 252, the boost section switch module 254, the boost section diode module 256, and the inverter module 258 are mounted on the same substrate. Because the boost section switch module 254 and the inverter module 258 are high-heat-generating components and require cooling, the substrates are mounted on a cooler. The cooler is designed based on the heat values ​​of the boost section switch module 254 and the inverter module 258, which are high-heat-generating components. Therefore, the rectifier circuit module 252, which is mounted on the same substrate, exhibits a reduced temperature rise compared to the boost section switch module 254 and the inverter module 258. 6, arranging the boost diode module 256, the inverter module 258, and the like around the rectifier circuit module 252 can act to promote a temperature rise in the rectifier circuit module 252. As a result, the power conversion device 1 according to the first embodiment can reduce losses by utilizing the negative temperature characteristics of the rectifier diodes 131 to 134, thereby improving the operating efficiency.

[0033] Although the closer the distance between the rectifier circuit module 252 and other modules, the better, it is necessary to satisfy the electrical insulation distance requirements stipulated by the standards. For this reason, the distance between the rectifier circuit module 252 and other modules must be equal to or greater than the minimum insulation distance set by the standards.

[0034] 6, the booster switch module 254, the booster diode module 256, and the inverter module 258 are arranged around the rectifier circuit module 252, but the arrangement is not limited to this, and it is sufficient that at least one of these is arranged around the rectifier circuit module 252. Furthermore, as will be described in the embodiment below, the reactor 135 is a component that generates more heat than the rectifier circuit module 252, so the reactor 135 may be arranged around the rectifier circuit module 252.

[0035] Furthermore, the rectifier diodes 131 to 134 are semiconductor elements, and it is not acceptable to increase the element temperature Tc indefinitely in order to reduce losses. For this reason, it is necessary to operate the power conversion device 1 taking the element temperature Tc into consideration. For this reason, in the power conversion device 1 according to the first embodiment, the operation of the converter 130 is controlled using the derating curve shown in FIG. 8. FIG. 8 is a diagram showing an example of the derating curve used in the power conversion device 1 according to the first embodiment.

[0036] The horizontal axis of Fig. 8 represents the element temperature, and the vertical axis represents the element current flowing through one rectifier diode. Furthermore, Tmax is the maximum rated temperature of the rectifier diode, and the solid line represents the upper limit of the element current. As shown in Fig. 8, the upper limit of the element current is kept constant until the element temperature Tc reaches the maximum rated temperature Tmax. Once the element temperature Tc exceeds the maximum rated temperature Tmax, the upper limit of the element current is gradually reduced at a certain gradient.

[0037] The temperature characteristic of the forward voltage Vf of a typical rectifier diode can be expressed by the following equation (1): Vf=Va-k Ｔ ×(Tc-Ta)...(1)

[0038] In the above formula (1), Va is the forward voltage when the forward current If is 0 [A], and k Ｔ is the temperature coefficient. Ta is the temperature of the environment in which the rectifier diode is placed. In this paper, this temperature is referred to as the "ambient temperature of the power conversion device" or simply as the "ambient temperature."

[0039] When the rectifying diode is a silicon diode, the temperature coefficient k Ｔ The value of k Ｔ = -2 [mV / °C] = -0.002 [V / °C].

[0040] FIG. 8 shows a derating curve, which is a control curve when the element temperature Tc exceeds the maximum rated temperature Tmax. However, the forward voltages Vf of the rectifier diodes 131 to 134 may be managed to operate the converter 130 so as to satisfy the following equation (2):

[0041] Vf>Va-k Ｔ ×(a×Tmax−Ta)…(2)

[0042] In the above formula (2), a is a temperature correction coefficient and is a real value not less than 0 and not more than 1. If the converter 130 is operated so as to satisfy the above formula (2), it becomes possible to operate the rectifier diodes 131 to 134 with the element temperature Tc of the rectifier diodes 131 to 134 not more than the maximum rated temperature Tmax while reducing the risk of deterioration and damage to the rectifier diodes 131 to 134.

[0043] Furthermore, in the power conversion device 1 according to the first embodiment, the rectifier circuit module 252 can effectively receive heat from at least one of the booster switch module 254, the booster diode module 256, and the inverter module 258, which are mounted on the same board. This results in a larger temperature rise in the rectifier circuit module 252 than when the rectifier circuit module 252 itself only generates heat.

[0044] Here, if the thermal resistance of the rectifier diodes 131 to 134 is Rth and the heat generation amount of the rectifier diodes 131 to 134 when the converter 130 is operating is Pd, the element temperature Tc of the rectifier diodes 131 to 134 can be expressed by the following equation (3) using the thermal resistance Rth, the heat generation amount Pd, and the ambient temperature Ta of the power conversion device.

[0045] Tc=Ta+Rth×Pd…(3)

[0046] Therefore, the power conversion device 1 of embodiment 1 has a unique feature that, during operation, the temperature of the rectifier diodes 131 to 134 becomes higher than the temperature calculated from the thermal resistance of the rectifier diodes 131 to 134.

[0047] As described above, the power conversion device according to the first embodiment includes a converter including a reactor, a first module accommodating a rectifying diode, and a second module accommodating one or more first switching elements for boosting a rectified voltage output from the first module, and an inverter that converts a DC voltage output by the converter into an AC voltage of a desired amplitude and phase and outputs the AC voltage to a motor. The reactor, the first module, and the second module are mounted on the same substrate. According to the power conversion device according to the first embodiment configured in this manner, the first module can receive heat from the second module mounted on the same substrate. Therefore, during converter operation, the temperature of the rectifying diode accommodated in the first module becomes higher than the temperature calculated from the thermal resistance of the rectifying diode. Therefore, by using the power conversion device according to the first embodiment, it is possible to improve the operating efficiency of the power conversion device while suppressing increases in the device size, cost, and number of components.

[0048] In the power conversion device according to the first embodiment, one or more circuit components that generate more heat than the rectifier diode are arranged around the first module. One of the circuit components that generates more heat is the second module. It is desirable that the second module be mounted on the same plane as the first module on the same substrate. If the second module is mounted on the same plane as the first module on the same substrate, the first module can efficiently receive heat from the second module.

[0049] In the power conversion device according to the first embodiment, one of the circuit components that generates a large amount of heat is the third module, which houses a diode used to boost the rectified voltage. The third module is preferably mounted on the same plane as the first module on the same substrate. If the third module is mounted on the same plane as the first module on the same substrate, the first module can efficiently receive heat from the third module.

[0050] In the power conversion device according to the first embodiment, one of the circuit components that generates a large amount of heat is the fourth module that houses the second switching element provided in the inverter. The fourth module is preferably mounted on the same plane as the first module on the same substrate. If the fourth module is mounted on the same plane as the first module on the same substrate, the first module can efficiently receive heat from the fourth module.

[0051] In the power conversion device according to the first embodiment, the forward voltage of the rectifier diode is Vf, the forward voltage when no current flows through the rectifier diode is Va, the maximum rated temperature of the rectifier diode is Tmax, the ambient temperature of the power conversion device is Ta, and the temperature coefficient of the rectifier diode is k. Ｔ and a predetermined temperature correction coefficient that takes a real value between 0 and 1, the power conversion device has a forward voltage characteristic of the rectifier diode that satisfies Vf>Va-k Ｔ The converter is controlled so as to satisfy the relationship of × (a × Tmax - Ta). If the converter is controlled in this manner, it becomes possible to operate the rectifier diode at an element temperature below the maximum rated temperature while reducing the risk of degradation and damage to the rectifier diode.

[0052] Embodiment 2. Fig. 9 is a diagram illustrating the essential points of the configuration of the power conversion device 1 according to embodiment 2. Fig. 9 shows an example of a mounting form of the rectifier circuit module 252 on the substrate 250 in the converter 130 of the power conversion device 1 according to embodiment 2. Specifically, Fig. 9 shows an example in which the rectifier circuit module 252 is mounted on the substrate 250 via a bonding member 510 so as to be in thermal contact with the current detection unit 501 mounted on the first main surface 251a of the substrate 250.

[0053] In the second embodiment, a current detection unit 501 is used as a method for applying heat to the rectifier diodes 131 to 134. The current detection unit 501 has a detection resistor for detecting the current flowing through the converter 130. Because the detection resistor is a resistive element, it generates heat when a current flows through the detection resistor. Therefore, the rectifier diodes 131 to 134 housed in the rectifier circuit module 252 can receive heat from the current detection unit 501. Even with this configuration, it is possible to improve the operating efficiency of the power conversion device 1.

[0054] The heat-generating component that provides heat to the rectifier circuit module 252 is not limited to the current detection unit 501, and may be a component other than the current detection unit 501. For example, the current detection unit 502 may be used instead of the current detection unit 501. Furthermore, both the current detection units 501 and 502 may be in thermal contact with the rectifier circuit module 252. Furthermore, a heat-generating component other than the current detection units 501 and 502 may be in thermal contact with the rectifier circuit module 252.

[0055] As described above, the power conversion device according to the second embodiment includes a detection resistor for detecting a current flowing through the power conversion device. The first module housing the rectifier diode is disposed in thermal contact with the detection resistor, with or without a bonding member. The detection resistor is one of the circuit components that generates a large amount of heat. Therefore, even when the power conversion device according to the second embodiment is used, it is possible to improve the operating efficiency of the power conversion device while suppressing increases in the device size, cost, and number of components.

[0056] Embodiment 3. In embodiment 2, an embodiment was described in which the rectifier circuit module 252 and a heat-generating component mounted on the same plane of the same substrate are in thermal contact with each other. In embodiment 3, an embodiment that is not limited to heat-generating components mounted on the same plane will be described.

[0057] Fig. 10 is a diagram illustrating the essential points of the configuration of the power conversion device 1 according to embodiment 3. Fig. 10 illustrates an example of a mounting configuration of the rectifier circuit module 252 on the substrate 250 in the converter 130 of the power conversion device 1 according to embodiment 3. Specifically, Fig. 10 illustrates an example in which the rectifier circuit module 252 is mounted on the first main surface 251a of the substrate 250, the reactor 135, which is one of the heat-generating components, is mounted on the second main surface 251b, which is the surface opposite to the first main surface 251a, and the rectifier circuit module 252 and the reactor 135 are electrically connected by a wiring pattern 512.

[0058] The reactor 135 is one of the heat-generating components, similar to the circuit components described in the first and second embodiments. The reactor 135 is a circuit component that generates more heat than the boost diode module 256 and the like. Furthermore, the reactor 135 has a winding (not shown), which is a component of the reactor 135, directly connected to the substrate 250, so that the heat generated in the reactor 135 can be transmitted to the rectifier circuit module 252 through the wiring pattern 512.

[0059] The closer the distance between the reactor 135 and the rectifier circuit module 252, the better, but it is necessary to satisfy the electrical insulation distance requirements stipulated by the standard. For this reason, the distance between the reactor 135 and the rectifier circuit module 252 is set to be equal to or greater than the minimum insulation distance set based on the standard.

[0060] Furthermore, when heat conduction is taken into consideration, the wider the pattern width of the wiring pattern 512, the better, but interference with other circuit components must also be taken into consideration. For this reason, the wiring pattern 512 is wired to the maximum width possible without interfering with other circuit components.

[0061] Furthermore, the heat generated in the reactor 135 is transmitted to the substrate 250 more from the windings directly connected to the substrate 250 than from the core (not shown), which is a component of the reactor 135. For this reason, when designing the reactor 135, it is desirable to design it so that the loss in the windings is greater than the loss in the core. By designing it in this way, it is possible to effectively transmit the heat generated in the reactor 135 to the rectifier circuit module 252.

[0062] 10 shows an example in which the reactor 135 is mounted on the second main surface 251b, which is the surface opposite to the first main surface 251a on which the rectifier circuit module 252 is mounted, but the present invention is not limited to this example. The reactor 135 may be mounted on the first main surface 251a on which the rectifier circuit module 252 is mounted, and the above-described effects can be obtained with this configuration as well.

[0063] As described above, according to the power conversion device of the third embodiment, the reactor, which is a circuit component of the converter, is mounted on the first main surface of the substrate on which the first module is mounted or on the second main surface opposite the first main surface. The first module and the reactor are electrically connected by a wiring pattern, the distance between the first module and the reactor is equal to or greater than the minimum insulation distance, and the wiring pattern is wired so that the pattern width is maximized without interfering with other circuit components. The reactor is one of the circuit components that generates a large amount of heat. Therefore, even when the power conversion device of the third embodiment is used, it is possible to improve the operating efficiency of the power conversion device while suppressing increases in the device size, cost, and number of components.

[0064] Fourth Embodiment Fig. 11 is a first diagram illustrating the main points of a first configuration of a power conversion device 1 according to a fourth embodiment, and Fig. 12 is a second diagram illustrating the main points of the first configuration of a power conversion device 1 according to the fourth embodiment. Fig. 11 shows an example of a mounting configuration of circuit components of a converter 130 on a substrate 250 in the power conversion device 1 that is different from that shown in Fig. 6. Fig. 11 also shows the direction in which cooling air flows.

[0065] 11 , in the first configuration of the power conversion device 1 according to the fourth embodiment, a rectifier circuit module 252, a booster switch module 254, a booster diode module 256, and an inverter module 258 are mounted on a first main surface 251 a of a substrate 250 so as to be aligned in a direction perpendicular to the direction of the flow of cooling air. As shown in FIG. 12 , a cooler 450 is provided below the portion where the booster switch module 254, the booster diode module 256, and the inverter module 258 are mounted.

[0066] 12 is characterized in that the thickness of the second base portion 452b below the rectifier circuit module 252, i.e., the base thickness of the portion on which the rectifier circuit module 252 is mounted, is thinner than the thickness of the first base portion 452a below the booster switch module 254, the booster diode module 256, and the inverter module 258, i.e., the base thickness of the portion on which the booster switch module 254, the booster diode module 256, and the inverter module 258 are mounted.

[0067] 12, the thermal resistance of the rectifier circuit module 252 can be increased compared to when the thickness of the second base portion 452b is equal to the thickness of the first base portion 452a. This can promote a temperature rise in the rectifier circuit module 252, thereby effectively improving the operating efficiency of the power conversion device 1.

[0068] 13 is a diagram illustrating the main points of a second configuration of the power conversion device 1 according to embodiment 4. The difference from the first configuration is that the spacing d2 between the cooling fins 456b at the portion where the rectifier circuit module 252 is mounted is wider than the spacing d1 between the cooling fins 456a at the portion where the booster switch module 254, the booster diode module 256, and the inverter module 258 are mounted.

[0069] 13, the thermal resistance of the rectifier circuit module 252 can be increased compared to when the spacing d2 of the cooling fins 456b is equal to the spacing d1 of the cooling fins 456a. This can promote a temperature rise in the rectifier circuit module 252, thereby effectively improving the operating efficiency of the power conversion device 1.

[0070] 14 is a diagram illustrating a main point of a third configuration of the power conversion device 1 according to the fourth embodiment. In the first and second configurations, the rectifier circuit module 252, the boost section switch module 254, the boost section diode module 256, and the inverter module 258 are mounted so as to be aligned in a direction perpendicular to the direction of the flow of the cooling air. In contrast, in the third configuration, the rectifier circuit module 252, the boost section switch module 254, the boost section diode module 256, and the inverter module 258 are arranged along the direction of the flow of the cooling air, and the rectifier circuit module 252 is arranged on the downwind side of the cooler with respect to the cooling air.

[0071] 14 , air heated by the heat of the boost section switch module 254, the boost section diode module 256, and the inverter module 258 flows through the cooling fins of the cooler (not shown in FIG. 14 ) at the location where the rectifier circuit module 252 is mounted. As a result, the cooling performance of the rectifier circuit module 252 is relatively lower than the cooling performance of the boost section switch module 254, the boost section diode module 256, and the inverter module 258. This can promote a temperature rise in the rectifier circuit module 252 compared to when the rectifier circuit module 252 is positioned on the upwind side of the cooler, thereby making it possible to effectively improve the operating efficiency of the power conversion device 1.

[0072] As described above, in the power conversion device according to the fourth embodiment, the converter has a third module accommodating a diode used for boosting the rectified voltage, and the inverter has a fourth module accommodating a second switching element provided in the inverter. When the first module, the second module, the third module, and the fourth module are mounted on the same cooler, the cooler is formed so that the base thickness of the portion on which the first module is mounted is thinner than the base thickness of the portions on which the second module, the third module, and the fourth module are mounted. In the power conversion device according to the fourth embodiment configured in this manner, the thermal resistance of the first module can be made relatively larger than the thermal resistances of the other modules, thereby making it possible to effectively improve the operating efficiency of the power conversion device.

[0073] In the power conversion device according to the fourth embodiment, the cooler may be configured such that the spacing between the cooling fins in the area where the first module is mounted is wider than the spacing between the cooling fins in the areas where the second, third, and fourth modules are mounted. This configuration makes it possible to more effectively improve the operating efficiency of the power conversion device.

[0074] In the power conversion device according to the fourth embodiment, the first module may be disposed so as to be on the downwind side of the cooler with respect to the cooling airflow. Even with such a disposition, it is possible to effectively improve the operating efficiency of the power conversion device.

[0075] Fifth Embodiment Fig. 15 is a diagram showing a configuration example of a refrigeration cycle-applied apparatus 900 according to a fifth embodiment. The refrigeration cycle-applied apparatus 900 according to the fifth embodiment includes the power conversion device 1 described in the first embodiment. The refrigeration cycle-applied apparatus 900 according to the fifth embodiment may also include the power conversion device 1 shown in Figs. 2 to 5. The refrigeration cycle-applied apparatus 900 according to the fifth embodiment may be applied to products equipped with a refrigeration cycle, such as air conditioners, refrigerators, freezers, and heat pump water heaters. In Fig. 15, components having the same functions as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

[0076] 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.

[0077] Inside the compressor 315, a compression mechanism 904 that compresses the refrigerant and a motor 314 that operates the compression mechanism 904 are provided.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 1 Power conversion device, 2 Motor drive device, 110 AC power supply, 130 Converter, 131 to 134 Rectifier diodes, 131a to 134a, 136, 136a to 136d, 311 Switching elements, 131b to 134b, 137, 137a to 137d, 312 Freewheeling diodes, 135 Reactor, 138 Boost diodes, 139, 210 Capacitor, 161 Rectifier circuit, 162 Boost circuit, 250 Substrate, 251a First main surface, 251b Second main surface, 252 Rectifier circuit module, 254 Boost switch module, 256 Boost diode module, 258 Inverter module, 310 Inverter, 314 Motor, 315 Compressor, 400 Control unit, 450 Cooler, 452a First base portion, 452b Second base portion, 454a First fin portion, 454b Second fin portion, 456a, 456b Cooling fins, 501, 502 Current detection portion, 510 Joining member, 512 Wiring pattern, 900 Refrigeration cycle applied device, 902 Four-way valve, 904 Compression mechanism, 906 Indoor heat exchanger, 908 Expansion valve, 910 Outdoor heat exchanger, 912 Refrigerant piping.

Claims

1. a converter including a reactor, a first module accommodating a rectifying diode for rectifying an AC voltage applied from an AC power supply, and a second module accommodating one or more first switching elements for boosting the rectified voltage output from the first module; an inverter connected in parallel to the converter, which converts a DC voltage output by the converter into an AC voltage of a desired amplitude and phase and outputs the AC voltage to a motor; Equipped with the reactor, the first module, and the second module are mounted on the same substrate, During operation of the converter, the temperature of the rectifier diode becomes higher than the temperature calculated from the thermal resistance of the rectifier diode. Power conversion device.

2. One or more circuit components that generate more heat than the rectifier diode are arranged around the first module. The power conversion device according to claim 1 .

3. one of the circuit components that generates a large amount of heat is the second module; The second module is mounted on the same plane as the first module on the same substrate. The power conversion device according to claim 2 .

4. Another one of the circuit components with a large heat generation amount is the reactor, the first module is mounted on a first main surface of the substrate, and the reactor is mounted on the first main surface of the substrate or a second main surface that is a surface opposite to the first main surface, the first module and the reactor are electrically connected by a wiring pattern; The distance between the first module and the reactor is set to be equal to or greater than the minimum insulation distance, and the pattern width of the wiring pattern is set to be maximum within a range where there is no interference with other circuit components. The power conversion device according to claim 2 .

5. The reactor is designed so that the loss in the winding section is greater than the loss in the core section. The power conversion device according to claim 4.

6. the other of the circuit components that generates a large amount of heat is a detection resistor for detecting a current flowing through the power conversion device, The first module is disposed in thermal contact with the detection resistor with or without a bonding member. The power conversion device according to claim 2 .

7. the converter has a third module containing a diode used to boost the rectified voltage; the inverter has a fourth module accommodating a second switching element provided in the inverter; the first module, the second module, the third module, and the fourth module are mounted on the same cooler; The cooler is formed so that the base thickness of the portion on which the first module is mounted is thinner than the base thicknesses of the portions on which the second module, the third module, and the fourth module are mounted. The power conversion device according to claim 1 .

8. The cooler is configured such that the spacing between the cooling fins in the area where the first module is mounted is wider than the spacing between the cooling fins in the areas where the second module, the third module, and the fourth module are mounted. The power conversion device according to claim 7.

9. the converter has a third module containing a diode used to boost the rectified voltage; the inverter has a fourth module accommodating a second switching element provided in the inverter; the first module, the second module, the third module, and the fourth module are mounted on the same cooler; The first module is disposed on the downwind side of the cooler with respect to the cooling air. The power conversion device according to claim 1 .

10. The forward voltage of the rectifier diode is Vf, The forward voltage when no current flows through the rectifier diode is Va, The maximum rated temperature of the rectifying diode is Tmax, The ambient temperature of the power conversion device is Ta, The temperature coefficient of the rectifying diode is k Ｔ year, When a is a predetermined temperature correction coefficient that takes a real value between 0 and 1, The forward voltage characteristics of the rectifier diode are as follows: _________________________ Ｔ × (1×) Satisfying the relationship The power conversion device according to claim 1 .

11. A motor drive device comprising the power conversion device according to any one of claims 1 to 10.

12. A refrigeration cycle device comprising the power conversion device according to any one of claims 1 to 10.