Power converter and electromechanical integrated motor

Abstract

This invention provides a power conversion device that reduces concerns about the discharge resistance failing. [Solution] The power conversion device 13 comprises a semiconductor element, a capacitor, and a discharge resistor 22. The semiconductor element converts power through switching operation and outputs power to the motor 12 for driving the vehicle. The capacitor is electrically connected to the semiconductor element. The discharge resistor 22 discharges the capacitor. The semiconductor element, capacitor, discharge resistor 22, and motor 12 are housed in a common case 130, and the discharge resistor 22 is positioned at least a portion of the motor 12 behind the vehicle.

Description

Technical Field

[0001] The disclosure in this specification relates to a power conversion device and an electromechanical integrated motor.

Background Art

[0002] Patent Document 1 describes a power conversion device having a discharge resistor. The discharge resistor is connected in parallel to a smoothing capacitor and discharges the charge stored in the smoothing capacitor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, the discharge resistor discharges the charge accumulated in the smoothing capacitor, aiming to reduce the risk of electric shock. However, when an external impact is applied due to a collision or the like, there remains a concern that the discharge resistor may be damaged and malfunction.

[0005] One disclosed object is to provide a power conversion device and an electromechanical integrated motor that reduce the concern of the discharge resistor malfunctioning.

Means for Solving the Problems

[0006] To achieve the above object, a power conversion device according to an aspect of the present disclosure includes a semiconductor element (32) that switches to convert power and outputs power to a motor (12) for driving a vehicle to travel, a capacitor (21) connected to be energizable to the semiconductor element, and a discharge resistor (22) that discharges the capacitor. The semiconductor element, the capacitor, the discharge resistor, and the motor are housed in a common case (130), and the discharge resistor is disposed on the rear side of the vehicle relative to at least a part of the motor.

[0007] According to the disclosed power conversion device, at least a portion of the motor is positioned in front of the discharge resistor. This ensures that in the event of an impact from the front of the vehicle, such as in a collision, the motor receives the impact before the discharge resistor. Since the motor is a highly rigid component, it can protect the discharge resistor from impacts such as vehicle collisions, preventing damage to the discharge resistor.

[0008] Furthermore, in order to achieve the above objective, a mechatronic integrated motor according to one aspect of the present disclosure comprises a motor (12) for driving a vehicle, a semiconductor element (32) that switches to convert power and outputs power to the motor, a capacitor (21) that is electrically connected to the semiconductor element, a discharge resistor (22) that discharges the capacitor, and a case (130) that houses the semiconductor element, capacitor, discharge resistor and motor, wherein the discharge resistor is positioned on the rear side of the vehicle from at least a part of the motor.

[0009] In the disclosed electromechanically integrated motor, similar to the power conversion device described above, at least a portion of the motor is positioned in front of the discharge resistor. This ensures that in the event of an impact from the front of the vehicle, such as in a collision, the motor receives the impact before the discharge resistor. Since the motor is a highly rigid component, it protects the discharge resistor from impacts such as vehicle collisions, preventing damage to the discharge resistor.

[0010] The reference numbers in parentheses above are merely examples of correspondences with specific configurations in the embodiments described later, and do not limit the technical scope in any way. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows the circuit configuration and drive system in a power conversion device according to the first embodiment. [Figure 2] This is a cross-sectional view showing a mechatronic motor equipped with a power conversion device according to the first embodiment. [Figure 3]It is a view taken along the arrow III-III in FIG. 2. [Figure 4] It is a cross-sectional view showing an electromechanical integrated motor according to another embodiment.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, a plurality of embodiments will be described based on the drawings. In each embodiment, the same reference numerals may be assigned to corresponding components, and redundant explanations may be omitted. When only a part of the configuration is described in each embodiment, the configuration of other embodiments described previously can be applied to other parts of the said configuration. Also, not only the combinations of configurations explicitly shown in the description of each embodiment, but also the configurations of a plurality of embodiments can be partially combined with each other as long as there is no problem with the combination, even if not explicitly shown.

[0013] (First Embodiment) First, based on FIG. 1, the schematic configuration of the drive system of a vehicle will be described.

[0014] <Drive System of Vehicle> The drive system 10 shown in FIG. 1 is mounted on a vehicle such as an electric vehicle (EV), a hybrid vehicle (HV), or a fuel cell vehicle. The drive system 10 has a battery 11, a motor 12, and a power conversion device 13. The drive system 10 is a system that drives the drive wheels of the vehicle by driving the motor 12.

[0015] The battery 11 is a DC voltage source composed of a rechargeable secondary battery, and corresponds to a power supply unit that supplies power to the motor 12 via the power conversion device 13. The secondary battery is, for example, a lithium ion battery or a nickel hydrogen battery. The battery 11 supplies a high voltage (for example, several hundred volts) to the inverter 30.

[0016] The motor 12 is a rotating electric machine using a three-phase alternating current system. The motor 12 has U-phase, V-phase, and W-phase as the three phases. The motor 12 functions as an electric motor that is a traveling drive source of the vehicle. The motor 12 functions as a generator during regeneration. Note that the motor 12 can also be referred to as a motor generator or an electric motor.

[0017] <Circuit Configuration of Power Conversion Device> The power conversion device 13 performs power conversion between the battery 11 and the motor 12. Here, the circuit configuration of the power conversion device 13 will be described while referring to FIG. 1. The power conversion device 13 includes a smoothing capacitor 21, a discharge resistor 22, an inverter 30, and a control device 35.

[0018] The smoothing capacitor 21 is a capacitor that smooths the DC voltage supplied from the battery 11. The smoothing capacitor 21 is connected to a P line 25 which is a high-potential side power line and an N line 26 which is a low-potential side power line. The P line 25 is connected to the positive electrode of the battery 11, and the N line 26 is connected to the negative electrode of the battery 11. The positive electrode of the smoothing capacitor 21 is connected to the P line 25 between the battery 11 and the inverter 30. Also, the negative electrode of the smoothing capacitor 21 is connected to the N line 26 between the battery 11 and the inverter 30. The smoothing capacitor 21 is connected in parallel with the battery 11. The smoothing capacitor 21 corresponds to a capacitor that is connected so as to be energizable to the arm switch 32 and is connected so as to be energizable to a semiconductor element that performs switching operation to convert power.

[0019] The discharge resistor 22 is a resistor that discharges the smoothing capacitor 21. The discharge resistor 22 is connected in parallel with the smoothing capacitor 21 in a state of being spanned between the P line 25 and the N line 26. One end of the discharge resistor 22 is connected to the N line 26 between the battery 11 and the smoothing capacitor 21. The other end of the discharge resistor 22 is connected to the P line 25 between the battery 11 and the smoothing capacitor 21.

[0020] For example, when the vehicle switch is switched off, the power stored in the smoothing capacitor 21 is consumed by the discharge resistor 22, and thus the smoothing capacitor 21 is discharged by the discharge resistor 22. The discharge resistor 22 generates heat as it consumes the power supplied from the smoothing capacitor 21.

[0021] The inverter 30 is a DC-AC conversion circuit. The inverter 30 is configured to include three-phase arm circuits 31. The arm circuit 31 is sometimes referred to as a leg. The arm circuit 31 has an upper arm 31a and a lower arm 31b respectively. The upper arm 31a and the lower arm 31b are serially connected between the P line 25 and the N line 26 with the upper arm 31a on the P line 25 side. The connection point between the upper arm 31a and the lower arm 31b is connected to the corresponding phase winding in the motor 12 via an output line 27. The arm circuit 31 and the output line 27 are provided for each of the U phase, V phase, and W phase of the motor 12. The inverter 30 has three upper arms 31a and three lower arms 31b respectively.

[0022] The arms 31a and 31b have an arm switch 32 and a diode 33. Note that the arm switch 32 corresponds to a semiconductor element that performs a switching operation to convert power and outputs power to the motor 12 for driving the vehicle to run. Examples of the arm switch 32 include an n-channel insulated gate bipolar transistor IGBT.

[0023] Arms 31a and 31b each have one arm switch 32 and one diode 33. In arms 31a and 31b, the diode 33 is connected in reverse parallel to the arm switch 32 for freewheeling. In the upper arm 31a, the collector of the arm switch 32 is connected to the P line 25. In the lower arm 31b, the emitter of the arm switch 32 is connected to the N line 26. The emitter of the arm switch 32 in the upper arm 31a and the collector of the arm switch 32 in the lower arm 31b are interconnected. The anode of the diode 33 is connected to the emitter of the corresponding arm switch 32, and the cathode is connected to the collector.

[0024] The inverter 30 converts the DC voltage to AC voltage according to the switching control of the control device 35 and outputs it to the motor 12. As a result, the motor 12 operates to generate a predetermined rotational torque. The inverter 30 converts the DC power from the battery 11 to three-phase AC power and acts as a power conversion unit. During regenerative braking of the vehicle, the inverter 30 converts the AC voltage generated by the motor 12 in response to the rotational force from the drive wheels to a DC voltage according to the switching control of the control device 35 and outputs it to the P line 25. In this way, the inverter 30 performs bidirectional power conversion between the battery 11 and the motor 12.

[0025] The control device 35 controls the drive of the inverter 30. The control device 35 is mainly composed of a microcomputer (hereinafter referred to as "microcontroller") equipped with, for example, a processor, memory, I / O, and a bus connecting these. The control device 35 executes various processes related to the drive of the inverter 30 by executing a control program stored in memory.

[0026] The control device 35 generates drive commands using signals input from higher-level ECUs such as the integrated ECU mounted on the vehicle, and signals input from various sensors such as current sensors, and causes the arm switch 32 to perform ON or OFF drives according to these drive commands.

[0027] Next, the structure of the power converter will be described based on Figures 2 and 3. The arrows in Figure 2 indicating up, down, front, and back indicate the front-rear and up-down directions of the vehicle when the integrated electromechanical motor is mounted on the vehicle. The up-down direction of the vehicle coincides with the vertical direction. The arrows in Figure 3 indicating front, back, left, and right indicate the front-rear and left-right directions of the vehicle when the integrated electromechanical motor is mounted on the vehicle.

[0028] <Positional relationship of each component> As shown in Figures 2 and 3, the power converter 13 includes a semiconductor unit 40, a capacitor unit 50, a control circuit board 60, a control device 35, a temperature sensor circuit 61, a discharge resistor 22, and an inverter case 110. In addition to the above configuration, the electromechanical motor includes a motor 12, a transmission 12b, and a motor case 120.

[0029] The inverter case 110 is made of metal and houses the semiconductor unit 40, capacitor unit 50, control circuit board 60, control device 35, temperature sensor circuit section 61, and discharge resistor 22. The inverter case 110 has an opening for inserting the control circuit board 60, and this opening is closed by a cover 111.

[0030] The motor case 120 houses the motor 12 and the transmission 12b. The motor case 120 is made of metal. The inverter case 110 is connected to the motor case 120, forming a single case 130. In other words, the power converter 13, together with the motor 12, constitutes a mechatronic integrated motor. The semiconductor unit 40, capacitor unit 50, control circuit board 60, control device 35, temperature sensor circuit 61, discharge resistor 22, transmission 12b, and motor 12 are all housed in a common case 130. The transmission 12b is a transmission that changes the speed (for example, reduces) of the motor 12's rotation and outputs it.

[0031] The electromechanical integrated motor is mounted on a vehicle. As shown in Figure 2, in this embodiment, the inverter case 110 is positioned above the motor case 120. The inverter case 110 is supported by, for example, bolts fastened to the motor case 120. The motor case 120 is supported by, for example, bolts fastened to a bracket on the vehicle body. The case 130 may be integrally molded from the inverter case 110 and the motor case 120 by die casting or the like.

[0032] The semiconductor unit 40 constitutes the arm circuit 31, i.e., the inverter 30. The semiconductor unit 40 has the aforementioned plurality of semiconductor elements 32 and a molding resin for molding the semiconductor elements 32. The semiconductor unit 40 is positioned below the control circuit board 60 in the vertical direction of the vehicle. The semiconductor unit 40 has control terminals (not shown) connected to the control circuit board, and main terminals (not shown) connected to the motor 12 and capacitor unit 50 via busbars.

[0033] The capacitor unit 50 includes the smoothing capacitor 21 described above and a capacitor case that houses the smoothing capacitor 21 inside. The capacitor unit 50 is positioned below the control circuit board 60 in the vertical direction of the vehicle.

[0034] The control circuit board 60 is equipped with a discharge resistor 22, a temperature sensor circuit 61, and a control device 35. The discharge resistor 22 is composed of multiple chip resistors mounted on the control circuit board 60 and connected in series or parallel. The number of discharge resistors is not limited by Figure 3. Also, in Figure 3, some of the reference numerals for the discharge resistor 22 have been omitted. The discharge resistor 22 is located in front of the vehicle, ahead of the temperature sensor circuit 61 and the control device 35. Note that the discharge resistor 22 does not have to be mounted on the control circuit board 60. For example, the discharge resistor 22 may be housed in a discharge resistor case and fixed inside the control circuit board 60 or the inverter case 110.

[0035] The control device 35 includes a microcontroller 36, a drive circuit unit 37, and a first connector 35b. The control device 35 is located behind the temperature sensor circuit unit 61 and the discharge resistor 22 in the vehicle. The microcontroller 36 controls the switching of the semiconductor element 32. The drive circuit unit 37 is configured with various first electronic components 37a and printed wiring mounted on the control circuit board 60. The drive circuit unit 37 supplies a drive voltage to the semiconductor element 32 based on a drive command from the microcontroller 36.

[0036] The temperature sensor circuit 61 is configured with various second electronic components 61a, a second connector 61b, and printed wiring mounted on the control circuit board 60. The temperature sensor circuit 61 detects the temperature of cooling water (not shown). The cooling water cools semiconductor elements 32 and the like that generate heat when power is applied. Based on the detected temperature data, for example, the flow rate of the cooling water is adjusted to maintain an optimal temperature range.

[0037] The temperature sensor circuit 61 is positioned between the discharge resistor 22 and the control device 35 in the longitudinal direction of the vehicle. In this embodiment, the temperature sensor circuit 61 is positioned between the discharge resistor 22 and the drive circuit 37 in the longitudinal direction of the vehicle. That is, they are arranged in the order of discharge resistor 22, temperature sensor circuit 61, and drive circuit 37 from the front of the vehicle. For example, the second electronic component 61a is positioned between the discharge resistor 22 and the first electronic component 37a in the longitudinal direction of the vehicle.

[0038] Furthermore, it is sufficient that at least a portion of the discharge resistor 22, temperature sensor circuit 61, and control device 35 are arranged in the order described above. In other words, any part of the discharge resistor 22, temperature sensor circuit 61, and control device 35 does not have to be in the order described above. For example, as shown in Figure 3, a portion of the control device 35 may overlap with the temperature sensor circuit 61 in the longitudinal direction of the vehicle.

[0039] As shown in Figures 2 and 3, at least a portion of the motor 12 is positioned forward of the discharge resistor 22. In this embodiment, the motor 12 is an inner rotor type with a rotor on the inside and a stator on the outside. The motor 12 is positioned so that its rotation axis direction is in the left-right direction of the vehicle. In this case, at least a portion of the stator (not shown) is positioned forward of the discharge resistor 22. Furthermore, in this embodiment, the control circuit board 60, semiconductor unit 40, and capacitor unit 50 are also positioned rearward of the vehicle, at least a portion of the motor 12.

[0040] <Effects and Effects in the First Embodiment> In this embodiment, the power converter 13 and the electromechanically integrated motor have the discharge resistor 22 positioned at least a portion of the motor 12 towards the rear of the vehicle. This ensures that when an impact is applied from the front of the vehicle, such as in a collision, the motor 12 receives the impact before the discharge resistor 22. Since the motor 12 is a highly rigid component, it protects the discharge resistor 22 from impacts caused by vehicle collisions, preventing damage to the discharge resistor 22.

[0041] Furthermore, the power converter 13 according to this embodiment has a microcomputer 36 that controls the switching of the semiconductor element 32, and the microcomputer 36 is positioned behind the discharge resistor 22 in the vehicle. As a result, in the event of a collision or other impact from the front of the vehicle, the motor 12 will be hit before the microcomputer 36. Therefore, the microcomputer 36 can be protected from impact, and the switching control will not malfunction. In other words, the function of discharging by outputting power to the motor 12 can be protected. In this case, the switching control is performed to convert as much energy as possible into thermal energy rather than kinetic energy.

[0042] Furthermore, the power converter 13 according to this embodiment includes a control device 35 that outputs a switching signal to the semiconductor element 32, and a temperature sensor circuit 61 that detects the temperature of the cooling water that cools the semiconductor element 32. The temperature sensor circuit is positioned between the discharge resistor 22 and the control device 35 in the longitudinal direction of the vehicle.

[0043] Here, the discharge resistor 22 is prone to overheating because a large current flows through it. The control device 35 is also prone to overheating. On the other hand, the temperature sensor circuit 61 generates little heat. Therefore, by placing the temperature sensor circuit 61, which does not generate much heat, between the heat-generating components, the discharge resistor 22 and the control device 35, thermal interference between the heat-generating components can be suppressed.

[0044] (Other embodiments) The disclosure in this specification is not limited to the exemplary embodiments. The disclosure encompasses the exemplary embodiments and variations thereof by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and elements shown in the embodiments, but can be implemented in various variations. The disclosure can be implemented in a variety of combinations. The disclosure may have additional parts that can be added to the embodiments. The disclosure encompasses embodiments in which parts and elements have been omitted. The disclosure encompasses substitutions or combinations of parts and elements between one embodiment and another. The scope of the disclosed technical field is not limited to the descriptions of the embodiments. The scope of the disclosed technical field is indicated by the claims and should be understood to include all modifications within the meaning and scope equivalent to the claims.

[0045] In the above embodiment, the discharge resistor 22 is positioned so as not to overlap with the motor 12 when viewed from the front of the vehicle. However, at least a portion of the discharge resistor 22 may overlap with the motor 12 when viewed horizontally from the front of the vehicle. Alternatively, as shown in Figure 4, the entire discharge resistor may overlap with the motor 12 in the above-mentioned view. This allows for a more effective protection of the discharge resistor 22 from impact and prevents damage, as described above.

[0046] In the above embodiment, a temperature sensor circuit 61 is positioned between the discharge resistor 22 and the control device 35 in the longitudinal direction of the vehicle, but it does not have to be positioned there. Alternatively, something other than the temperature sensor circuit 61 may be positioned there. For example, instead of the temperature sensor circuit 61, a component that performs an interlock function may be positioned there. In this case as well, thermal interference between the heat-generating component, the discharge resistor 22, and the control device 35 can be suppressed.

[0047] The interlock function detects, for example, whether a connection is made to the battery 11 or an external ECU, and permits the inverter 30 to operate only if a connection is detected. Specific examples of components responsible for the interlock function include switches, harnesses, and connectors (not shown). A switch detects whether a connection is made. A harness transmits a detection signal output from the switch. A connector is connected to the harness and transmits the detection signal to the microcontroller 36.

[0048] In the above embodiment, a passive discharge resistor is used as the discharge resistor 22. However, an active discharge resistor whose energization is controlled by the control device 35 may be provided separately. In this case, it is desirable that the active discharge resistor is also positioned at least a portion of the motor 12 on the rear side of the vehicle. [Explanation of Symbols]

[0049] 12 motor, 130 case, 21 capacitor, 22 discharge resistor, 32 semiconductor element, 35 control unit, 36 microcomputer, 61 temperature sensor circuit.

Claims

1. A semiconductor element (32) that switches to convert power and outputs power to a motor (12) for driving the vehicle, A capacitor (21) is connected to the semiconductor element in a way that allows current to flow through it, The capacitor is discharged by a discharge resistor (22), The semiconductor element, the capacitor, the discharge resistor, and the motor are housed in a common case (130). The discharge resistor is a power converter located on the rearward side of the vehicle from at least a portion of the motor.

2. The power conversion device according to claim 1, wherein at least a portion of the discharge resistor overlaps with the motor in a projected view from the front of the vehicle.

3. The power conversion device according to claim 2, wherein the entire discharge resistor overlaps the motor in the projected view.

4. The system includes a microcomputer (36) that controls the switching of the semiconductor element, The power conversion device according to any one of claims 1 to 3, wherein the microcomputer is located behind the vehicle relative to the discharge resistor.

5. A control device (35) that outputs a switching signal to the semiconductor element, It includes a temperature sensor circuit (61) for detecting the temperature of the cooling water used to cool the semiconductor element, The power conversion device according to any one of claims 1 to 3, wherein the temperature sensor circuit is arranged between the discharge resistor and the control device in the longitudinal direction of the vehicle.

6. A motor (12) for driving the vehicle, A semiconductor element (32) that performs a switching operation to convert power and output power to the motor, A capacitor (21) is connected to the semiconductor element in a way that allows current to flow through it, The discharge resistor (22) for discharging the capacitor, The device comprises the semiconductor element, the capacitor, the discharge resistor, and a case (130) housing the motor, The discharge resistor is located on the rearward side of the vehicle from at least a portion of the motor, in a mechatronic motor.

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