Power conversion device

Abstract

Electrical current conversion device (10), comprising: a first electrical current transformer (13a) that converts an alternating current generated by a first electric rotary machine (8a) coupled to an internal combustion engine into a direct current; a second electrical current transformer (13b) that converts a direct current into an alternating current and supplies this alternating current to a second electric rotary machine (8b) coupled to drive wheels (17); a direct current converter (12) that changes the voltage of a battery (2); a first current sensor (4) that measures a current between the first electrical current transformer (13a) and the first electric rotary machine (8a); a second current sensor (5) that measures a current between the second electrical current transformer (13b) and the second electric rotary machine (8b);a DC converter current sensor (3) that measures a current between the battery (2) and the DC converter (12); a first sensor current source (15a) that supplies electrical energy to the first current sensor (4) and the DC converter current sensor (3); and a second sensor current source (15b) that supplies electrical energy to the second current sensor (5).

Description

Technical area

[0001] The present application relates to a power conversion device. background

[0002] Hybrid electric vehicles, in which an electric power generator is driven by an internal combustion engine to generate electrical energy, and an electric motor is driven by the generated electrical energy to drive the drive wheels, have been put into practice. Hybrid electric vehicles each have a battery, so that when the internal combustion engine is turned off, electrical energy is supplied from the battery to drive the vehicle's drive wheels. When the internal combustion engine is running, the battery is charged by the electrical energy from the power generator generated by the internal combustion engine. Even during operation of the internal combustion engine, the electrical energy supplied by the battery can be used, if necessary, together with the electrical energy generated by the power generator to drive the electric motor with greater power.

[0003] An AC motor in the form of a brushless three-phase motor is often used as the electric motor for driving an electric vehicle. The current generated by the electric power generator is converted into a direct current, which serves as a direct current source for charging the battery. Furthermore, an alternating current is generated from the direct current source with the help of a DC-AC converter (electrical current converter). This current drives the AC motor.

[0004] In such an electric vehicle hybrid, vector control is applied to the primary current of the electric motor using the DC-AC converter to generate a target output power for propulsion. Furthermore, the output power of the internal combustion engine is controlled to generate the required electrical energy as the output of the DC-AC converter. In this regard, a technique has been proposed in which an output current of the electric power generator and a current supplied by the battery are measured using current sensors to precisely control the supplied current (for example, Patent Document 1). Citation listPatent literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. H05-146008 Summary of the inventionTechnical problem

[0006] To more accurately control the output power for driving the hybrid electric vehicle, a current sensor can be used to measure the electric current output of the DC-DC converter that supplies electric power to the electric motor that drives the drive wheels. In addition to the current sensor that measures the output of the electric power generator and the current sensor that measures the DC power supply from the battery, the current sensor that measures the output of the DC-DC converter that drives the electric motor is an important sensor. Since one electric power source is usually used to drive all these sensors, if one such sensor power source fails, all the current sensors become inoperable, making current control difficult. As a result, the electric vehicle is difficult to drive. Patent Document 1 does not describe a countermeasure to the above-mentioned problem.

[0007] Every vehicle must be capable of performing an emergency evacuation trip if its components fail partially, even in a power-limited state. This capability is called "limp home." "Limp home" is a feature that effectively allows the vehicle to reach the owner's home even at low speed.

[0008] If separate sensor power sources are configured as the sensor power source for each of the different types of current sensors, sensors other than the sensor corresponding to that sensor power source can still be used even if one of those sensor power sources fails. However, if the sensor power sources are provided completely separately, the number of sensor power sources and the number of power supply lines of the sensor power sources increase, resulting in an increase in size, weight, and cost of an electrical power conversion device. Reducing weight, size, and cost is a prerequisite for instruments to be mounted on vehicles. Accordingly, it is necessary to optimally balance the improved fault tolerance with the promoted reduction in weight, size, and cost.

[0009] The present application is intended to solve the above-mentioned problem related to the electric power conversion device, wherein an object is to provide an electric power conversion device in which the number of sensor power sources for different types of current sensors is minimized while at the same time ensuring a "limp home" function in response to a failure of the sensor power source. Solution to the problem

[0010] An electrical power conversion device disclosed in this application comprises: a first electric power converter that converts an alternating current generated by a first electric rotary machine coupled to an output shaft of an internal combustion engine into a direct current and outputs this direct current through its DC terminal; a second electrical current converter connected to the DC terminal and converting a direct current into an alternating current and supplying the alternating current to a second rotating electrical machine coupled to a drive wheel; a DC-DC converter connected between a battery and the DC terminal to cause a voltage change; a first current sensor that measures a current flowing between the first electrical current transformer and the first electrical rotary machine; a second current sensor that measures a current flowing between the second electrical current transformer and the second electrical rotating machine; a DC-DC converter current sensor that measures a current flowing between the battery and the DC-DC converter; a first sensor power source that supplies electrical energy to the first current sensor and the DC-DC converter current sensor; and a second sensor current source that supplies electrical energy to the second current sensor. Advantageous effects of the invention

[0011] In accordance with the electric power conversion device according to this application, due to the provision of: the first sensor power source that supplies electrical energy to a current sensor for the first electric power converter that converts an alternating current generated by the first electric rotary machine driven by the internal combustion engine into a direct current, and to a current sensor that measures a current of the DC converter that increases the voltage of the battery; and the second sensor power source, which supplies electrical energy to a current sensor for the second electrical current converter, which supplies the second electrical rotary machine coupled to the drive wheels with an alternating current, It is possible to provide an electrical power conversion device in which the number of sensor power sources is minimized while ensuring a "limp home" function in response to a sensor power source failure. This makes it possible to reduce the number of sensor power sources in an electrical power conversion device, thereby reducing its size, weight, and cost. Short description of the drawings Fig. 1 is a configuration diagram of an electric power conversion device according to Embodiment 1. Fig. 2 is a hardware configuration diagram of a control device in the electric power conversion device according to Embodiment 1. Fig. 3 is a circuit diagram of a first electric power converter in the electric power conversion device according to Embodiment 1. Fig. 4 is a circuit diagram of a second electric power converter in the electric power conversion device according to Embodiment 1. Fig. 5 is a diagram showing a state of electric power supply when the sensor power sources in the electric power conversion device according to Embodiment 1 are all normal. Fig. 6 is a first diagram showing a state of electric power supply when a first sensor power source has failed in the electric power conversion device according to Embodiment 1. Fig. 7 is a second diagram showing a state of electric power supply when the first sensor power source has failed in the electric power conversion device according to Embodiment 1. Fig. 8 is a diagram showing the state of electric power supply when a second sensor power source has failed in the electric power conversion device according to Embodiment 1. Fig. 9 is a diagram showing the state of electric power supply when a second sensor power source has failed in an electric power conversion device according to Embodiment 2. Description of the embodiments

[0012] Hereinafter, embodiments of electrical power conversion devices according to this application will be described in accordance with the drawings. 1. Embodiment 1<Konfigurieren von elektrischen Stromumwandlungsvorrichtungen>

[0013] Fig. Figure 1 is a configuration diagram of an electric power conversion device 10 according to Embodiment 1. The electric power conversion device 10 is electrically connected to: a battery 2 of a vehicle 1; a first electric rotary machine 8a dynamically coupled to an output shaft of an internal combustion engine 6; and a second electric rotary machine 8b dynamically coupled to drive wheels 17. This dynamic coupling may be a direct coupling of main shafts, a coupling via a reduction gear and a clutch, or a coupling via a rotation transmission mechanism using a belt. Fig. 1, the internal combustion engine 6 is shown as “ENG”, the first electric rotary machine 8a as “M1” and the second electric rotary machine 8b as “M2”.

[0014] The first rotating electric machine 8a and the second rotating electric machine 8b may each be an AC rotating electric machine provided with a U-phase winding, a V-phase winding, and a W-phase winding. The first rotating electric machine 8a and the second rotating electric machine 8b can not only rotate a load but also regenerate electrical energy from the rotational energy of the load. As the first rotating electric machine 8a and the second rotating electric machine 8b, an electric motor having a rotor provided with a permanent magnet, an electric motor having a rotor provided with an electromagnet, a brush-type electric motor, a brushless electric motor, or the like can be used.

[0015] The electric power conversion device 10 includes a first electric power converter 13a, a second electric power converter 13b, a DC-DC converter 12, a control device 14, a sensor power source 15, a first current sensor 4, a second current sensor 5, and a DC-DC converter current sensor 3. Due to the output of the internal combustion engine 6 mounted on the vehicle 1, the first electric rotary machine 8a is driven to generate electric power, and alternating currents according to the generated electric power are converted into direct current by the first power converter 13a, and this direct current is output via a positive-side DC terminal 23a and a negative-side DC terminal 23b.

[0016] The second electric power converter 13b, to which the direct current is supplied via the positive-side DC terminal 23a and the negative-side DC terminal 23b, converts the direct current into alternating current, thereby rotating the second electric rotary machine 8b to drive the drive wheels 17. The DC-DC converter 12 changes the voltage of the battery 2 mounted on the vehicle 1 and sends / receives a direct current to / from the positive-side DC terminal 23a and the negative-side DC terminal 23b. When needed, a current is supplied from the battery 2 to the positive-side DC terminal 23a and the negative-side DC terminal 23b, and when the battery 2 is charged, it receives a current from the positive-side DC terminal 23a and the negative-side DC terminal 23b.

[0017] Currents flowing through the first electrical current transformer 13a, the second electrical current transformer 13b, and the DC-DC converter 12 are detected by the first current sensor 4, the second current sensor 5, and the DC-DC converter current sensor 3, respectively. Electrical energy is supplied to the first current sensor 4 and the DC-DC converter current sensor 3 from a first sensor power source 15a via a first sensor power supply line 9a. Electrical energy is supplied to the second current sensor 5 from a second sensor power source 15b via a second sensor power supply line 9b. Fig. 1, the first sensor current source 15a and the second sensor current source 15b are integrated into the sensor current source 15. However, the first sensor current source 15a and the second sensor current source 15b can be positioned separately at different positions.

[0018] The control device 14 imports the detection signals of the first current sensor 4 via an input terminal I1, imports the detection signals of the second current sensor 5 via an input terminal I2, and imports the detection signal of the DC-DC converter current sensor 3 via an input terminal IC. The control device 14 controls the second electric current converter 13b via a control terminal C2. Thus, the control device 14 can control the amount of current for driving the second electric rotary machine 8b according to a driving force required by the vehicle 1.

[0019] The control device 14 controls the first electric power converter 13a via a control terminal C1. In this way, the control device 14 can control the power supply to be generated and delivered by the first electric rotary machine 8a according to the electrical energy required by the vehicle 1. The control device 14 can adjust the output power of the internal combustion engine 6 using a signal from a control terminal CE. By adjusting the output power of the internal combustion engine 6 and controlling the rotation speed of the internal combustion engine 6, the control device 14 can control the currents to be generated by the first electric rotary machine 8a.

[0020] The DC-DC converter 12 increases the voltage of the battery 2 to a voltage above the positive-side DC terminal 23a and the negative-side DC terminal 23b. Information about a current supplied by the battery 2 or a current for charging the battery 2 is transmitted as a signal from the DC-DC converter current sensor 3 to the input terminal IC of the control device 14. <Hardware-Konfiguration der Vorrichtung zur Steuerung>

[0021] Fig. 2 is a hardware configuration diagram of the control device 14 according to Embodiment 1. The respective functions of the control device 14 are implemented by a processing circuit included in the control device 14. As shown in Fig. 2, the control device 14 includes, as processing circuitry: an arithmetic processing device 90 (also referred to as a processor) such as a CPU (Central Processing Unit) or the like; storage devices 91 that perform data transactions with the arithmetic processing device 90; interfaces such as an input circuit 92 that inputs external signals to the arithmetic processing device 90, an output circuit 93 that externally outputs signals from the arithmetic processing device 90; and the like.

[0022] As the arithmetic processing device 90, an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), any of a plurality of logic circuits, any of a plurality of signal processing circuits, or the like may be included. In addition, a plurality of arithmetic processing devices 90 of the same type or different types may be included so that the respective parts of the processing are executed together.

[0023] Included in the control device 14 are, as storage devices 91, a RAM (Random Access Memory) configured to enable reading and writing of data by the arithmetic processing device 90, a ROM (Read Only Memory) configured to enable reading of data by the arithmetic processing device 90, and the like. The storage device 91 may be integrated into the arithmetic processing device 90. Input signals, sensors, and switches are connected to the input circuit 92, so that the input circuit includes AD converters for inputting the input signals and signals from the sensors and switches to the arithmetic processing device 90. Specifically, the signals from the first current sensor 4, the second current sensor 5, and the DC-DC converter current sensor 3 are input thereto. Electrical loads, such asA gate drive circuit that drives switching elements to be turned on and off, etc., are connected to the output circuit 93, so that the output circuit includes a drive circuit and the like for outputting control signals from the arithmetic processing device 90 to these electrical loads. Specifically, output signals for driving switching elements of the first electrical power converter 13a, the second electrical power converter 13b, and the DC-DC converter 12 are output.

[0024] The respective functions included in the control device 14 are implemented such that the arithmetic processing device 90 executes software (programs) stored in the storage device 91 such as the ROM or the like, thereby cooperating with the other hardware in the control device 14, such as the other storage device 91, the input circuit 92, the output circuit 93, and so on. Note that the setting values, determination values, and the like to be set by the control device 14 are stored as part of the software (programs) in the storage device 91 such as the ROM or the like. Each of the functions of the control device 14 can be implemented by a software module; however, it can also be implemented by a combination of software and hardware. <gleichstromwandler>

[0025] The DC converter 12 in Fig. 1 functions as a voltage conversion device that converts between the voltage of the battery 2 and the voltage at the positive-side DC terminal 23a and the negative-side DC terminal 23b. The DC-DC converter 12 is also referred to as a DC-DC converter. The DC-DC converter 12 includes a reactor 7, a positive-side switching element 16b, a negative-side switching element 16a, and the DC-DC converter current sensor 3, which detects a reactor current.

[0026] The DC-DC converter 12 is connected to a low-voltage side smoothing capacitor 21, which smooths a DC voltage on the low-voltage side, and a high-voltage side smoothing capacitor 22, which smooths a DC voltage on the high-voltage side. The positive-side switching element 16b and the negative-side switching element 16a are controlled by the control device 14.

[0027] The positive-side switching element 16b and the negative-side switching element 16a are connected in series to form a switching circuit in the DC-DC converter 12. The negative-side switching element 16a may be configured as a plurality of switching elements connected in parallel. The positive-side switching element 16b may also be configured as a plurality of switching elements connected in parallel.

[0028] The positive-side switching element 16b and the negative-side switching element 16a are subjected to switching control using gate signals from the control terminals G1 and G2 of the control device 14, respectively. For example, the positive-side switching element 16b and the negative-side switching element 16a each consist of an IGBT (Insulated Gate Bipolar Transistor) to which a freewheeling diode is reverse-connected. As another example, a FET (Field Effect Transistor) to which a parasitic diode is reverse-connected in parallel can be used as the switching element. A conventional bipolar transistor with a diode reverse-connected in parallel can also be used as such a switching element.

[0029] The DC-DC converter 12 increases the voltage of the direct current output from the battery 2 and then supplies this current to the first electric current converter 13a and the second electric current converter 13b. After the alternating currents generated by the first rotary electric machine 8a are converted into direct current by the first electric current converter 13a, the voltage corresponding to this current is decreased by the DC-DC converter 12 to charge the battery 2. The DC-DC converter 12 functions as a voltage step-up or step-down converter. <Erster elektrischer Stromwandler>

[0030] Fig. 3 is a circuit diagram of the first electric power converter 13a in the electric power conversion device 10 according to Embodiment 1. The first electric power converter 13a functions as an AC-DC converter that converts the three-phase AC currents output from the first rotary electric machine 8a into DC currents.

[0031] The first electrical power converter 13a includes positive-side switching elements 16d, 16f, and 16h for U-phase, V-phase, and W-phase, which are connected to the positive-side DC terminal 23a; and negative-side switching elements 16c, 16e, and 16g for U-phase, V-phase, and W-phase, which are connected to the negative-side DC terminal 23b. These switching elements, like the positive-side switching element 16b and the negative-side switching element 16a of the DC-DC converter 12, are each configured with an IGBT or the like and connected to a freewheeling diode connected in parallel in reverse bias. The positive-side switching elements for each phase are referred to as an upper arm, and the negative-side switching elements for each phase are referred to as a lower arm. The upper arm and the lower arm for each phase are connected in series so that a three-phase alternating current for the U-phase, V-phase or W-phase is supplied through the connection point of them.

[0032] The connection points for the respective phases are connected to the respective windings of the first electric rotary machine 8a, and the currents flowing through the respective phases are detected by first current sensors 4a, 4b, and 4c for the respective phases. According to Fig. 1, it was described that the detection current signals of the first current sensor 4 are imported into the control device 14 via its input terminal I1. Three input terminals through which the respective detection values ​​of the first current sensor 4a for the U-phase, the first current sensor 4b for the V-phase, and the first current sensor 4c for the V-phase are actually imported are represented by the input terminal I1 as a generic term.

[0033] The respective switching elements of the first electrical current transformer 13a are controlled via the control terminals C11 to C16 of the control device 14. In Fig. 1, the control terminals C11 to C16 are represented by the control terminal C1 as a generic term. While monitoring the measured values ​​of the first current sensor 4, which measures the output currents, the control device 14 controls the corresponding switching elements and the output power of the internal combustion engine 6 so that the output current of the first power generator 13a attains a target value. Namely, the first current sensor 4 is provided to cause the control device 14 to perform feedback control of the output of the first electrical power converter 13a.

[0034] The three-phase alternating currents supplied to the first electric power converter 13a are rectified by the switching elements and converted into direct current, which is then supplied to the positive-side DC terminal 23a and the negative-side DC terminal 23b. The first electric rotary machine 8a sometimes functions as an electric power generator that generates power and sometimes as an electric motor to which power is supplied. The first electric power converter 13a sometimes functions as a DC-DC converter and sometimes as an AC-DC converter. When the engine is turned off, the first electric power converter 13a converts the direct current from the battery 2, whose voltage has been changed by the DC-DC converter 12, into alternating current to drive the first electric rotary machine 8a, thereby activating the engine 6. <Sekundärer elektrischer Stromwandler>

[0035] Fig. 4 is a circuit diagram of the second electric power converter 13b in the electric power conversion device 10 according to Embodiment 1. The second electric power converter 13b functions as a DC-DC converter that converts the DC power supplied via the positive-side DC terminal 23a and the negative-side DC terminal 23b into three-phase AC power for driving the second rotary electric machine 8b.

[0036] The second electric power converter 13b includes positive-side switching elements 16j, 16l, and 16n for U-phase, V-phase, and W-phase, which are connected to the positive-side DC terminal 23a; and negative-side switching elements 16i, 16k, and 16m for U-phase, V-phase, and W-phase, which are connected to the negative-side DC terminal 23b. These switching elements, like the positive-side switching elements 16b, 16d, 16f, and 16h and the negative-side switching elements 16a, 16c, 16e, and 16g of the DC-DC converter 12 and the first electric power converter 13a, are each configured with an IGBT or the like and provided with a freewheeling diode connected in parallel in reverse bias. The positive-side switching elements for each phase are referred to as an upper arm, and the negative-side switching elements for each phase are referred to as a lower arm.The upper arm and the lower arm for each phase are connected in series so that a three-phase alternating current for the U-phase, V-phase or W-phase is supplied through the connection point of them.

[0037] The connection points for the respective phases are connected to the respective windings of the second electric rotary machine 8b, and the currents flowing through the respective phases are detected by second current sensors 5a, 5b, and 5c for the respective phases. According to Fig. 1, it was described that the detection current signals of the second current sensor 5 are imported into the control device via its input terminal I2. Three input terminals, through which the respective detection values ​​of the second current sensor 5a for the U-phase, the second current sensor 5b for the V-phase, and the second current sensor 5c for the W-phase are actually imported, are represented by the input terminal I2 as a generic term.

[0038] The respective switching elements of the second electrical current transformer 13b are controlled via the control terminals C21 to C26 of the control device 14. In Fig. 1, the control terminals C21 to C26 are represented by the control terminal C2 as a generic term. By monitoring the measured values ​​of the second current sensor 5, which measures the output currents, the control device 14 controls the respective switching elements so that the output currents of the second electric power generator 13b each receive a target value. The second current sensor 5 is provided to cause the control device 14 to perform feedback control of the outputs of the second electric power converter 13b.

[0039] The direct current supplied to the second electric power converter 13b is controlled by the switching elements with load to thereby be converted into three-phase alternating currents, which are then supplied to the U-phase, V-phase, and W-phase coils of the second electric rotary machine 8b. The second electric rotary machine 8b sometimes functions as an electric motor driven by the currents supplied to it and sometimes as an electric power generator that generates currents. The second electric power converter 13b sometimes functions as a DC-to-AC converter and sometimes as an AC-to-DC converter. When the vehicle 1 decelerates, the second electric power converter 8b is driven by the drive wheels 17 to thus function as an AC generator, and the second electric power converter 13b converts the thus generated electrical energy from AC to DC to charge the battery 2. <sensor-stromquelle>

[0040] The first current sensor 4, the second current sensor 5, and the DC-DC converter current sensor 3 each receive an electrical power supply for the sensor from the sensor power source 15. Reducing the size, weight, and cost of vehicle instruments is a prerequisite. Therefore, it is also desirable for the sensor power sources to minimize the placement of the power sources and the cables to the sensors.

[0041] As in Fig. As shown in Fig. 1, in the electric power conversion device 10 according to Embodiment 1, three current sensors are provided, namely the first current sensor 4, the second current sensor 5, and the DC-DC converter current sensor 3. Two power sources, i.e., the first sensor power source 15a and the second sensor power source 15b, are set as electric power sources for driving these sensors, and two lines, i.e., the first sensor power supply 9a and the second sensor power supply 9b, are used as power supply lines, so that a reduction in size, weight, and cost is achieved while improving fault tolerance. Note that this plurality of sensor elements may be of the same type; however, sensor elements of different types may be used. <Stromfluss bei normalen Sensor-Stromquellen>

[0042] Fig. Figure 5 is a diagram showing a state of electric power supply when the sensor power sources in the electric power conversion device according to Embodiment 1 are all normal. A transmitted driving force acting on the first rotating electric machine 8a driven by the engine 6 is indicated by a white arrow. The alternating currents generated by the first rotating electric machine 8a are converted into direct currents by the first electric power converter 13a.

[0043] The thus converted direct current is then converted into alternating current by the second electrical current converter 13b to drive the second electric rotary machine 8b. This current flow is indicated by arrows. A transmitted driving force acting on the drive wheels 17 driven by the second electric rotary machine 8b is indicated by another white arrow. Fig. 5, the currents to be detected by the first current sensor 4 are indicated by "I1", the currents to be detected by the second current sensor 5 are indicated by "I2", and a current to be detected by the DC-DC converter current sensor 3 is indicated by "IC".

[0044] The battery 2 causes a DC change with the DC converter 12, and the DC converter 12 causes a DC change with the first electrical current converter 13a and the second electrical current converter 13b. In Fig. In Figure 5, the group of current transformers subject to feedback control by means of the current sensors powered by the first sensor current source 15a is indicated by a region 20a. The current transformer subject to control by the current sensor powered by the second sensor current source 15b is indicated by a region 20b. <Stromfluss, wenn die erste Sensor-Stromquelle ausgefallen ist>

[0045] Fig. 6 is a first diagram showing a state of electric power supply when the first sensor power source 15a fails in the electric power conversion device 10 according to Embodiment 1. When the first sensor power source 15a or the first sensor power line 9a fails, the first current sensor 4 and the DC-DC current sensor 3 lose the electric power for operating these sensors and therefore cannot detect the currents.

[0046] In this case, the control device 14 cannot perform feedback control with respect to the first electric power converter 13a and the DC-DC converter 12. This means that the first electric power converter 13a cannot operate normally, and the DC-DC converter 12 cannot perform voltage step-up and voltage step-down operations.

[0047] The DC-DC converter 12 can no longer use the DC-DC converter current sensor 3 and therefore can no longer perform voltage boosting and voltage-decreasing operations. In this case, the control device 14 continuously turns on the positive-side switching element 16b and continuously off the negative-side switching element 16a using the gate signals output from the control terminals G1 and G2, so that the DC terminal can be connected to the battery 2 without interruption.

[0048] The drive state of the DC-DC converter at this time is referred to as "direct drive." Direct drive allows the second electric current converter 13b to be supplied with a current supply from the battery 2. The current flow at this time is indicated by an arrow. In this case, the output currents of the second electric current converter 13b are detectable by the second current sensor when the sensor current source 15b is normal. Accordingly, it is possible to perform current feedback control of the second electric rotary machine 8b.

[0049] Fig. 7 is a second diagram showing a state of electric power supply when the first sensor power source fails in the electric power conversion device according to Embodiment 1. The first electric power converter 13a cannot operate normally, so its operation is stopped. However, the first electric power converter 13a can function as a three-phase rectification circuit even during the interruption of its drive because the freewheeling diodes are reversely connected in parallel with the respective switching elements.

[0050] In this situation, it is permissible to increase the rotation speed of the internal combustion engine 6 by a control command from the control device 14. This makes it possible to control an induction voltage generated by the first electric rotary machine 8a that is greater than the voltage of the battery 2. Accordingly, it is possible to supply the currents generated by the first electric rotary machine 8a, which is driven by the internal combustion engine 6, to the second electric power generator 13b and the battery 2 via the three-phase full-wave rectification. Fig. 7 the current flow at this time is indicated by an arrow.

[0051] For example, assuming that the voltage of the battery 2 is 14.7 V, a rotation speed of the engine 6 at which the induction voltage of the first rotating electric machine 8a exceeds the voltage of the battery can be measured and set in advance. The control device 14 can control the engine 6 to achieve the thus defined rotation speed or more. Furthermore, a battery voltage sensor that detects the voltage of the battery 2 can be provided. The control device 14 can control the engine 6 to have a rotation speed at which the induction voltage is generated that exceeds the detection value of the battery voltage sensor.

[0052] By providing a first rotating electric machine voltage sensor that detects the output voltage of the first rotating electric machine 8a, the induced voltage generated by the first rotating electric machine 8a can also be detected. Upon detecting an abnormality of the first sensor power source 15a, the control device 14 adjusts the rotation speed of the internal combustion engine so that the induced voltage detected by the first rotating electric machine voltage sensor is greater than the battery voltage detected by the battery voltage sensor. This increases the security that the currents generated by the first electric rotary machine 8a, which is driven by the internal combustion engine 6, are supplied to the second electric current converter 13b and the battery 2 by three-phase full-wave rectification.

[0053] Even if the first sensor power source 15a fails, the second electric power converter 13b can operate normally. Since the second current sensor 5 is powered by the power supplied from the second sensor power source 15b, the control device 14 can place the second electric power converter 13b under feedback control. With the power supplied by the battery 2 when the DC-DC converter 12 is under direct drive and the current generated by the first electric power converter 13a, and due to the supplied three-phase full waves, the second electric power converter 13b can accurately drive the second rotating electric machine 8b.

[0054] In this way, the vehicle 1 can control the second rotating electric machine 8b even if the first sensor power source 15a has failed. When the DC-DC converter 12 is controlled to be directly connected, the voltage at the DC terminal drops, so that the currents provided by the second electric power converter 13b to drive the second rotating electric machine 8b are restricted. However, the travel of the vehicle 1 is permitted by driving the drive wheels 17, so that the emergency running function can be ensured. Furthermore, when the rotation speed of the internal combustion engine 6 is increased, it is possible to charge the battery 2 with the currents generated by the first rotating electric machine 8a. This makes it possible to extend the travel time and distance of the vehicle 1 according to the charge state of the battery 2 at that time. <Stromfluss, wenn zweite Sensor-Stromquelle ausgefallen ist>

[0055] Fig. 8 is a diagram showing the state of the electric power supply when the second sensor power source 15b fails in the electric power conversion device 10 according to Embodiment 1. When the second sensor power source 15b or the second sensor power line 9b fails, the second current sensor 5 loses the electric power for operating this sensor and therefore cannot detect the currents.

[0056] In this case, the control device 14 cannot perform current feedback control with respect to the second electric power converter 13b. However, the control device 14 can predictively control the second electric rotating machine 8b by driving the switching elements of the second electric power converter 13b with PWM (Pulse Width Modulation) so that the currents required to drive the second electric rotating machine 8b each have a predetermined pulse width corresponding to these currents. Accordingly, it is possible to ensure the "limp home" function even if it is not possible to perform high-precision feedback control with the second current sensor 5 for the output currents.

[0057] Since the first sensor power source 15a is provided to supply electrical power to the first current sensor 4 for the first electrical power converter 13a and the DC-DC converter current sensor 3, and the second sensor power source 15b is provided to supply electrical power to the second current sensor 5 for the second current converter 13b, it is possible to provide such an electrical power conversion device 10 in which the number of sensor power sources is minimized while ensuring the "limp home" function in response to a sensor power source failure. This makes it possible to reduce the number of sensor power sources in the electrical power conversion device 10, thereby reducing its size, weight, and cost. 2. Embodiment 2

[0058] Fig. 9 is a diagram showing the state of an electric power supply when a second sensor power source 15b fails in an electric power conversion device 10a according to Embodiment 2. The embodiment of the electric power conversion device 10a according to Embodiment 2 differs from the embodiment of the electric power conversion device 10 according to Embodiment 1 in that a third electric power converter 13c is added. A control device 14a controls the switching elements of the third electric power converter 13c, in addition to those of the first electric power converter 13a and the DC-DC converter 12 (the control device 14a is not illustrated).

[0059] A vehicle 1a to which the electric power conversion device 10a according to Embodiment 2 is mounted includes a third electric rotary machine 8c. In Fig. In FIG. 1, the third rotating electric machine 8c is illustrated as "M3." The third rotating electric machine 8c is used as a rear rotating electric machine for traveling, driving the rear wheels 17a. A target driven by the third rotating electric machine 8c may instead be the drive wheels 17. The third rotating electric machine 8c is driven by currents supplied from the third electric power converter 13c. Otherwise, the electric power conversion device 10a according to Embodiment 2 is the same as the electric power conversion device 10 according to Embodiment 1. <Stromfluss, wenn zweite Sensor-Stromquelle ausgefallen ist>

[0060] If the second sensor power source 15b or the second sensor power line 9b is defective, the second current sensor 5 loses the electrical power needed to operate this sensor and therefore cannot detect the currents. In this case, the control device 14a cannot perform current feedback control with respect to the second electrical current converter 13b.

[0061] In this case, the third electric power converter 13c can also operate normally. A current resulting from the voltage conversion of the electric power of the battery 2 by the DC-DC converter 12 and supplied to the DC terminal, and a current based on the electric power generated by the first rotating electric machine 8a and supplied to the DC terminal by the first electric power converter can be supplied to the third electric power converter 13c. This allows the control device 14a to control the third electric power converter 13c to supply power to the third rotating electric machine 8c, thereby driving the rear wheels 17a to achieve travel.

[0062] In this case, the second electrical current converter 13b is no longer driven. The second electrical rotary machine 8b is set in rotation by the drive wheels 17. Since the second electrical rotary machine 8b is rotated in this way, an inverse electromotive force is generated. The second electrical rotary machine 8b functions as an electrical energy generator, so that a direct current is generated in the second electrical current converter 13b due to the rectifying action of the freewheeling diodes, which are connected in reverse to the switching elements of the current converter. This current intervenes in the control of the third electrical current converter 13c. As the rotation speed of the drive wheels 17 increases, the induced voltage of the second electrical rotary machine 8b increases.Therefore, in order to suppress the induction voltage of the second rotary electric machine 8b, it is not allowed to increase the traveling speed beyond a certain speed at the time of limping.

[0063] However, if the control device 14a causes the DC-DC converter 12 to perform a voltage boost operation, it is possible to reduce noise due to the induced voltage of the second rotating electric machine 8b. Accordingly, an appropriate step voltage higher than its normal step voltage can be predetermined for the DC-DC converter 12. Then, the control device 14a causes the DC-DC converter 12 to perform an operation up to the predetermined step voltage. Instead, the DC-DC converter 12 can step up the voltage to its maximum rated voltage.

[0064] To drive the third electric rotary machine 8c through the third electric current converter 13c, a third current sensor may be provided that detects the outputs of the third electric current converter 13c to apply high-precision current feedback control. In this case, the electric power supply for the third current sensor may be received from the first sensor power source 15a. This allows the control device 14a to accurately perform current control of the third electric current converter 13c even if the second sensor power source 15b or the second sensor power line 9b is defective. Fig. 9, the currents to be detected by the third current sensor are indicated by "I3".

[0065] In Embodiment 2, when the first sensor power source 15a or the first sensor power line 9a fails, the control device 14a stops driving the first electrical power converter 13a and controls the direct connection of the DC power source 12. In this case, it is possible to take measures and ensure the "limp home" function as described in Embodiment 1, so further description is omitted.

[0066] As described above, according to the electric power conversion device 10a according to Embodiment 2, it is possible to provide an electric power conversion device 10a in which the number of sensor power sources is minimized while ensuring a satisfactory limp-home function in response to a sensor power source failure. This makes it possible to reduce the number of sensor power sources in the electric power conversion device 10a, thereby reducing its size, weight, and cost.

[0067] A variety of exemplary embodiments and examples are described in this application; however, each feature, configuration, or function described in one or more embodiments is not limited to application to a particular embodiment and may be applied to another embodiment alone or in any of various combinations thereof. Accordingly, an infinite number of modified examples not exemplified herein are contemplated within the technical scope disclosed in the description of this application. For example, cases are included where at least one configuration item is changed; where at least one configuration item is added or omitted; and further, where at least one configuration item is extracted and combined with a configuration element of another embodiment.

[0068] Various embodiments disclosed above are summarized in the following appendices. (Appendix 1)

[0069] Electrical power conversion device comprising: a first electric power converter that converts an alternating current generated by a first electric rotary machine coupled to an output shaft of an internal combustion engine into a direct current and outputs this direct current through its DC terminal; a second electrical current converter connected to the DC terminal and converting a direct current into an alternating current and supplying this alternating current to a second electric rotary machine coupled to a drive wheel; a DC-DC converter connected between a battery and the DC terminal to cause a voltage change; a first current sensor that measures a current flowing between the first electrical current transformer and the first electrical rotary machine; a second current sensor that measures a current flowing between the second electrical current transformer and the second electrical rotating machine; a DC-DC converter current sensor that measures the current flowing between the battery and the DC-DC converter; a first sensor power source that supplies electrical energy to the first current sensor and the DC-DC converter current sensor; and a second sensor current source that supplies the second current sensor with electrical energy. (Appendix 2)

[0070] An electric power conversion device according to claim 1, comprising a control device that controls the DC-DC converter; wherein the DC-DC converter comprises a positive-side switching element, a negative-side switching element, and a reactor; and wherein the controller, when detecting an abnormality of the first sensor current source, puts the DC-DC converter under direct control. (Appendix 3)

[0071] The electric power conversion device according to claim 2, wherein the control device turns on the positive-side switching element and turns off the negative-side switching element upon detection of an abnormality of the first sensor power source. (Appendix 4)

[0072] The electric power conversion device according to claim 2 or 3, further comprising a battery voltage sensor that detects a voltage of the battery, and a first electric rotating machine voltage sensor that detects an output voltage of the first electric rotating machine; wherein the controller, upon detecting an abnormality of the first sensor power source, adjusts a rotation speed of the internal combustion engine such that an induced voltage detected by the first electric rotating machine voltage sensor is greater than a battery voltage detected by the battery voltage sensor. (Appendix 5)

[0073] Electrical power conversion device according to one of claims 2 to 4, wherein, when the first sensor current source and the second sensor current source are normal, the control device controls the first electric current converter based on a current value detected by the first current sensor, controls the second electric current converter based on a current value detected by the second current sensor, and controls the DC-DC converter based on a current value detected by the DC-DC converter current sensor; and when an abnormality of the second sensor current source is detected, the control device controls the second electric current transformer without using a current value detected by the second current sensor. (Appendix 6)

[0074] An electrical power conversion device according to any one of claims 2 to 5, further comprising a third electrical power converter connected to the DC terminal and converting a direct current into an alternating current and supplying the alternating current to a third electric rotary machine coupled to a drive wheel, wherein, when an abnormality of the second sensor power source is detected, the control device stops driving the second electric current converter and controls the first electric current converter, the third electric current converter and the DC-DC converter. (Appendix 7)

[0075] An electric power conversion device according to claim 6, further comprising a third current sensor that measures a current flowing between the third electric power converter and the third electric rotary machine, wherein the third current sensor receives an electrical power supply from the first sensor power source. (Appendix 8)

[0076] The electric power conversion device according to claim 6 or 7, wherein, upon detecting an abnormality of the second sensor power source using the DC-DC converter, the device increases a voltage at the DC terminal to a predetermined voltage higher than a normal voltage at a time when the second sensor power source is normal. (Appendix 9)

[0077] The electric power conversion device according to claim 8, wherein the device increases the voltage at the DC terminal to a maximum rated voltage upon detection of an abnormality of the second sensor power source using the electric power converter. (Appendix 10)

[0078] Electrical power conversion device according to one of claims 1 to 9, wherein, when the internal combustion engine is to be activated, the first electric power converter drives the first electric rotary machine while converting the direct current provided via the direct current connection into an alternating current; and wherein, when the second rotating electric machine regenerates electric energy, the second electric power converter converts an alternating current generated by the second rotating electric machine into a direct current and outputs the direct current to the direct current terminal. Description of reference numbers

[0079] 2: battery, 3: DC-DC converter current sensor, 4: first current sensor, 5: second current sensor, 6: internal combustion engine, 8a: first electric rotary machine, 8b: second electric rotary machine, 8c: third electric rotary machine, 10, 10a: electric power conversion device, 12: DC-DC converter, 13a: first electric power converter, 13b: second electric power converter, 13c: third electric power converter, 14, 14a: control device, 15a: first sensor power source, 15b: second sensor power source, 16a: negative-side switching element, 16b: positive-side switching element, 17: drive wheels, 17a: rear wheels. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 05-146008

[0005] < / gleichstromwandler>

Claims

[1] An electrical power conversion device comprising: a first electric power converter that converts an alternating current generated by a first electric rotary machine coupled to an output shaft of an internal combustion engine into a direct current and outputs the direct current through its direct current terminal; a second electrical current converter connected to the DC terminal and converting a direct current into an alternating current and supplying the alternating current to a second rotary electric machine coupled to a drive wheel; a DC-DC converter connected between a battery and the DC terminal to cause a voltage change; a first current sensor that measures a current flowing between the first electrical current transformer and the first electrical rotary machine; a second current sensor that measures a current flowing between the second electrical current transformer and the second electrical rotary machine; a DC-DC converter current sensor that measures a current flowing between the battery and the DC-DC converter; a first sensor power source that supplies electrical power to the first current sensor and the DC-DC converter current sensor; and a second sensor current source that supplies electrical energy to the second current sensor. [2] An electric power conversion device according to claim 1, comprising a control device that controls the DC-DC converter; wherein the DC-DC converter comprises a positive-side switching element, a negative-side switching element, and a reactor; and wherein the control device, when detecting an abnormality of the first sensor power source, puts the DC-DC converter under direct drive. [3] The electric power conversion device according to claim 2, wherein the control device turns on the positive-side switching element and turns off the negative-side switching element upon detection of an abnormality of the first sensor power source. [4] The electric power conversion device according to claim 2 or 3, further comprising a battery voltage sensor that detects a voltage of the battery, and a first electric rotating machine voltage sensor that detects an output voltage of the first electric rotating machine; wherein, upon detecting an abnormality of the first sensor power source, the controller adjusts a rotation speed of the internal combustion engine so that an induced voltage detected by the first electric rotating machine voltage sensor is greater than a battery voltage detected by the battery voltage sensor. [5] An electrical power conversion device according to any one of claims 2 to 4, wherein, when the first sensor current source and the second sensor current source are normal, the control device controls the first electric current converter based on a current value detected by the first current sensor, controls the second electric current converter based on a current value detected by the second current sensor, and controls the DC-DC converter based on a current value detected by the DC-DC converter current sensor; and when an abnormality of the second sensor current source is detected, the control device controls the second electric current converter without using a current value detected by the second current sensor. [6] The electric power conversion device according to any one of claims 2 to 5, further comprising a third electric power converter connected to the DC power terminal and converting a direct current into an alternating current and supplying the alternating current to a third electric rotary machine coupled to a drive wheel, wherein, when an abnormality of the second sensor power source is detected, the control device stops driving the second electric power converter and controls the first electric power converter, the third electric power converter and the DC converter. [7] The electric power conversion device according to claim 6, further comprising a third current sensor that measures a current flowing between the third electric power converter and the third electric rotary machine, the third current sensor receiving electric power supply from the first sensor power source. [8] The electric power conversion device according to claim 6 or 7, wherein the control device, upon detecting an abnormality of the second sensor power source using the DC-DC converter, increases a voltage at the DC terminal to a predetermined voltage higher than a normal voltage at a time when the second sensor power source is normal. [9] The electric power conversion device according to claim 8, wherein the control device, upon detecting an abnormality of the second sensor power source, increases the voltage at the DC terminal to a maximum rated voltage using the DC-DC converter. [10] Electrical power conversion device according to one of claims 1 to 9, wherein, when the internal combustion engine is to be activated, the first electric power converter drives the first electric rotary machine while converting the direct current provided via the direct current connection into an alternating current; and wherein, when the second rotating electric machine regenerates electric energy, the second electric power converter converts an alternating current generated by the second rotating electric machine into a direct current and outputs the direct current to the direct current terminal.

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