JP4357279B2 - Converter circuit in electric vehicle control device - Google Patents

Description

  The present invention relates to a converter circuit in an electric vehicle control device.

  FIG. 2 shows a configuration of a conventional representative electric vehicle control apparatus for AC power reception. This conventional electric vehicle control device basically includes a transformer 1, a three-level converter circuit (CON) 2, a three-level inverter circuit (INV) 3, and a drive motor 4.

  In the case of a high-speed train such as a Shinkansen train, the input current ISA of the converter circuit 2 increases in accordance with the acceleration of the electric vehicle. For example, in a wide range of a constant output region of 100 km / h to 250 km / h as shown in FIG. Maximum. The operation of the converter circuit 2 in this constant output region is as follows.

  FIG. 4 shows the details of the three-level converter circuit 2 in the conventional electric vehicle control device, and FIGS. 5 and 6 show the gate time chart of the semiconductor switching element and the voltage and current waveforms of the main circuit. Although the semiconductor switching elements 11 to 18 in FIG. 4 are described as one piece on the drawing, they are actually two parallel connections.

  In the case of an electric vehicle control apparatus for driving a Shinkansen train in Japan, the voltage / current of the intermediate link voltage EFCP = EFCN = 1200 V to 1500 V and the input current ISA (max) = 1000 A to 1200 A in FIG. An IGBT (Insulated Gate Bipolar Transistor) rated at 3300V-1200A is used as a semiconductor switching element of a three-level converter circuit that meets the above requirements.

  The operation of the three-level converter circuit 2 will be described with respect to the positive half cycle T period of the AC power source in which the input current ISA is shown in FIGS. 4, 5, and 6. The gate time chart of the T period shown in FIGS. 5 and 6 means the following mode. In the U phase, U1 element 11 is on, U2 element 12 is on, U3 element 13 is off, U4 element 14 is off, and U1 element 11 is off and U2 element 12 is on as the second mode. , U3 element 13 is on, and U4 element 14 is off. In the V phase, the V1 element 15 is off, the V2 element 16 is on, the V3 element 17 is on, the V4 element 18 is off, and the V1 element 15 is off and the V2 element 16 is off as the fourth mode. Off, V3 element 17 is on, and V4 element 18 is on. A combination of these modes operates a positive half cycle.

  That is, as shown in FIG. 7, in the second mode of the U phase and the fourth mode of the V phase, the IGBT power source of the U3 element 13 from the AC power supply 5 and the leakage inductance 6 of the transformer → the diode 52 → the capacitor 72 → the V4 element 18 A current flows through a path of the diode portion → the diode portion of the V3 element 17 → the AC power source 5 to charge the DC voltage O to N (EFCN in FIG. 2).

  Next, as shown in FIG. 8, in the first mode of the U phase and the third mode of the V phase, the AC power supply 5 → the leakage inductance 6 of the transformer → the diode part of the U2 element 12 → the diode part of the U1 element 11 → the capacitor 73 → Diode 53 → IGBT portion of V2 element 16 → Current flows through the path of AC power supply 5 and charges between DC voltage PO (same EFCP). A negative half-cycle is also operated in the same manner.

  As described above, the input current ISA flows through the IGBT portion only in the inner semiconductor switching elements U3 or U2 and V2 or V3, and the flow through the diode portion is the same in both the inner and outer elements. Therefore, a large loss is generated from the IGBT portions of the inner semiconductor switching elements U2, U3, V2, and V3, but there is almost no loss from the IGBT portion of the outer semiconductor switching elements U1, U4, V1, and V4. For this reason, semiconductor switching element coolers tend to increase the number of cooling systems that do not use refrigerants due to environmental problems, such as recently, so it is necessary to determine the cooling performance based on the generation loss of the inner elements, and the size of the cooler There was a problem.

  The present invention has been made in view of the above-described conventional technical problems, and the generation loss per element of the semiconductor switching element connected to the outside of the three-level converter circuit and the semiconductor switching element connected to the inside is reduced. It is an object of the present invention to provide a converter circuit in an electric vehicle control device that can achieve equalization and consequently reduce the size of a cooler.

According to the first aspect of the present invention, an AC power source is input to a converter circuit and converted into a DC voltage, and the DC voltage is input to an inverter circuit to be converted into a variable voltage and a variable frequency voltage to be output for a load motor. A converter circuit in a vehicle control device, comprising U-phase and V-phase semiconductor switching means sandwiching a connection point between a positive electrode side and a negative electrode side and inside the positive electrode side and the negative electrode side at a position close to the connection point. The three-level converter circuit is provided with semiconductor switching means on the positive and negative sides at positions far from the connection point, and the semiconductor switching means outside the U phase and V phase has two semiconductor switching elements. The semiconductor switching means is configured by connecting in parallel, and each of the U-phase and V-phase inner semiconductor switching means is more than the outer semiconductor switching element. A semiconductor switching element having a small rated current is connected in parallel .

  According to the present invention, the semiconductor switching elements on the outside of the three-level converter circuit are arranged in parallel in the conventional manner, and the semiconductor switching elements on the inside are constituted by four parallel semiconductor switching elements having a small rated current, thereby providing one semiconductor switching element. The generated loss per element can be equalized, and as a result, the cooler can be miniaturized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. A converter circuit in an electric vehicle control apparatus according to one embodiment of the present invention will be described with reference to FIG. The electric vehicle control apparatus including the converter circuit of the present embodiment has the configuration shown in FIG. 2 as in the conventional example.

  The converter circuit (CON) 2 in such an electric vehicle control device has the configuration shown in FIG. 1 and is a three-level converter circuit. The semiconductor switching elements 11, 21 and 14, 24 outside the U phase are, for example, 3300 V− Two 1200A rated elements are arranged in parallel, and the inner semiconductor switching elements 12, 22, 32, 42 and 13, 23, 33, 43 are arranged, for example, in parallel with 3300V-800A rated elements. Similarly, in the V phase, the outer semiconductor switching elements 15, 25, 18, and 28 have, for example, two 3300V-1200A rated elements in parallel, and the inner semiconductor switching elements 16, 26, 36, 46 and 17, 27, 37, 47. Has, for example, four parallel 3300V-800A rated elements. Each set of semiconductor switching elements is simultaneously turned on / off. In FIG. 1, 5 is an AC power source, and 6 is a leakage inductance of the transformer. Reference numerals 51 to 64 denote diodes, and reference numerals 71 to 74 denote filter capacitors.

  The converter circuit 2 of the present embodiment is driven by the gate signal shown in FIG. 5 as in the conventional example, and performs the AC-DC conversion action shown in FIG. At that time, the switching operation is the same as that of the conventional example shown in FIGS.

  The converter circuit 2 of the present embodiment has the above configuration, for example, when the DC voltage EFCP = EFCN = 1200 V, the input current ISA = 1100 A, and the PWM carrier frequency of the converter circuit 2 is 1260 Hz, it is per one inner semiconductor switching element. Since the generation loss is half that of the conventional configuration shown in FIG. 4, the IGBT portion is about 620 W, the diode portion is about 320 W, and the generation loss per one outer semiconductor switching element is the diode portion about 690 W. As described above, in the conventional configuration, the generated loss per inner semiconductor switching element is IGBT part = 1420 W and the diode part = 690 W. In this embodiment, the loss per element is greatly increased. Equalized. Recently, cooling structures that do not use a refrigerant tend to increase due to environmental problems, and since the temperature rise of the element mounting portion is determined by the generated loss per element, the generated loss of each semiconductor switching element as in this embodiment If the equalization can be achieved, the converter circuit cooler can be optimized, and a cooler corresponding to the generated loss lower than the conventional one can be adopted. As a result, the cost can be reduced and the cooler can be downsized.

1 is a circuit diagram of a three-level converter circuit according to one embodiment of the present invention. A circuit diagram of a typical main circuit system for AC power reception. The graph which shows the power running performance characteristic of high-speed vehicles, such as a Shinkansen train. The circuit diagram of the conventional typical 3 level converter circuit. The gate time chart of the said conventional 3 level converter circuit. FIG. 3 is a waveform diagram of voltages and currents at various parts of the conventional three-level converter circuit. FIG. 1 is a diagram for explaining the operation of the conventional three-level converter circuit. FIG. 2 is a diagram for explaining the operation of the conventional three-level converter circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transformer 2 ... Converter circuit 3 ... Inverter circuit 4 ... Motor 11-47 ... Semiconductor switching element 51-64 ... Diode 71-74 ... Filter capacitor

Claims (1)

A converter circuit in an electric vehicle control device that inputs an AC power source to a converter circuit to convert it to a DC voltage, and further converts the DC voltage to an inverter circuit to convert it to a variable voltage / variable frequency voltage for output to a load motor. There,
In each of the U phase and the V phase, a positive electrode side and a negative electrode side connection point are sandwiched, semiconductor switching means inside the positive electrode side and the negative electrode side are provided at positions close to the connection point, and the positive electrode side is provided at a position far from the connection point. , A three-level converter circuit provided with semiconductor switching means on the outer side of each negative electrode side ,
The U-phase and V-phase outer semiconductor switching means are configured by connecting two semiconductor switching elements in parallel, and the U-phase and V-phase inner semiconductor switching means are more rated than the outer semiconductor switching elements. 4. A converter circuit in an electric vehicle control apparatus , wherein four semiconductor switching elements having a small current are connected in parallel .

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