JPS62268303A - Auxiliary power circuit for rolling stock - Google Patents

Abstract

PURPOSE:To improve the reliability of a main circuit and entire auxiliary power system, by obtaining power source from AC terminals of a main PWM inverter through a transformer. CONSTITUTION:A cooler 1 as AC load is connected to a main PWM inverter 2 on AC output side connected to an electric car line 3 through a starter 4 and a smoothing capacitor 5. An auxiliary power unit 7 is composed of a three- phase transformer 71, a rectifier 72 and a converter 73 on its output side. Thus, an auxiliary power circuit of rolling stock is obtained, which can be small-sized, lightweight, at low price and of high reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an auxiliary power supply circuit for a vehicle equipped with a PWM (Pulse Width Modulation) inverter.

[Conventional technology]

Normally, electric vehicles must obtain all power sources, such as vehicle drive power, cooling/heating power, lighting power, battery charger, and control power, from overhead contact lines or the third rail. In the case of DC trains, the voltage of these overhead contact lines is 600v DC ~
The voltage is 1500V, and the high voltage reaches 3000V DC, and all the power sources of the vehicle are powered by this DC 600~3000V.
Must be obtained from the V overhead contact line or third rail.

Figure 3 is a circuit diagram showing a conventional example of a power supply system that uses a main inverter to obtain power for vehicle cooling. It is driven by

The main PWM inverter 2 is connected to a starting device 4 configured with a filter switch or the like connected to the overhead contact line 3, and between the starting device 4 and the main PWM inverter 20, an inverter 2 flowing to the overhead contact line 3 side is connected. A smoothing capacitor 5 is connected in parallel for suppressing input harmonic current.

In the figure, reference numeral 6 denotes an auxiliary power supply device for obtaining control power for the inverter 2, and this is connected to the output side of the starting device 4 of the main power supply circuit.

FIG. 4 shows an example of the basic circuit of the auxiliary power supply device 6, which includes an auxiliary PWM inverter 61 that converts direct current to alternating current, an auxiliary PWM inverter 61 that is insulated from the main power circuit, and that converts the AC voltage of the inverter 61 to the required voltage. A rectifier 63 is connected to this inverter 61 via an isolation transformer 62 that steps down the voltage up to .

In this way, the main voltage of the rectifier 63 is adjusted by PWM control of the inverter 61, and the DC output of the rectifier 63 is supplied as AC power via a DC/AC converter (not shown) as necessary. However, in order to obtain two or more types of power, various types of alternating current and direct current can be obtained by providing a plurality of secondary windings of the transformer 62 or providing taps.

[Problem that the invention seeks to solve]

In the conventional auxiliary power supply circuit shown in FIGS. 3 and 4, the semiconductor elements used in the auxiliary PWM inverter 61 for the auxiliary power supply are the same as the elements of the main PWM inverter 2, for example, 2500 V or higher. A high-voltage self-extinguishing element with a withstand voltage of Generally, high voltage self-extinguishing elements of 2500 V or higher include GTO Cyrisk, but these elements are large current elements and are expensive.

If such an element is applied to an inverter for a small capacity auxiliary power supply, the auxiliary power supply device 6 will become very expensive and large.

In addition, the power of the auxiliary power supply device 6 can be directly connected to the main PW of the main power supply circuit.
Since it is taken from the same DC main circuit as M inverter 2, the auxiliary P
A failure of the WM inverter 61 directly affects the operation of the main PWM inverter 2, reducing the reliability of the entire power supply circuit.

Furthermore, the protection measures against failure of the auxiliary PWM inverter 61 are the same as those of the main PWM inverter 2, making the auxiliary power supply device 6 even more expensive.

The present invention eliminates the disadvantages of the conventional example and provides a vehicle auxiliary power supply circuit that is small and lightweight, inexpensive, and highly reliable for use in inverter-equipped vehicles.

[Means for solving problems]

In order to achieve the above object, the present invention provides an auxiliary power supply circuit for a vehicle in a DC electric vehicle that supplies power to an AC load from a DC power supply supplied from an overhead contact line or a third rail via a PWM inverter. The gist of this is to obtain power from the AC output of the PWM inverter via a transformer.

[Effect]

According to the present invention, the line voltage of the AC output of the main PWM inverter of the main power supply circuit is P
Focusing on the fact that it is a WM-controlled square wave AC voltage,
Auxiliary power is obtained from between the AC terminals of the main PWM inverter via a transformer.

Since the auxiliary power converter is thereby connected to the secondary side of the transformer, the withstand voltage of the semiconductor element used in the converter can be freely selected.

Further, since only a highly reliable transformer is connected to the main power circuit side, there is no possibility that failure of the auxiliary power converter or the like will adversely affect the main inverter.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment of an auxiliary power supply circuit for a vehicle according to the present invention, in which the same components as in FIG. 3 showing the conventional example are given the same reference numerals.

That is, the main power supply circuit is the same as the conventional example, and 1 is a tara as an AC load, which is the AC output of the main PWM inverter 2 connected to the overhead contact line 3 via a starting device 4 and a smoothing capacitor 5. Although these are connected to the side, the detailed explanation thereof will be omitted since it is as described above.

In the figure, 7 is an auxiliary power supply, which is a three-phase transformer 71.
It is composed of a rectifier 72 and a converter 73 on its output side,
The transformer 71 is connected to the AC output side of the main PWM inverter 2.

In this way, the necessary auxiliary power is obtained from the output 8L 82 of the converter 73, but this converter 73 is a DC/DCC/type converter when a DC power source is required for the output, and a DC/DCC/type converter is used when an AC power source is required for the output. becomes a DC/AC converter.

Next, to explain the operation with reference to FIG. 2, the main PW in FIG.
The AC output line voltage of the M inverter 2 is a PWM-controlled rectangular wave AC voltage whose peak value is the overhead line voltage Ed as shown in FIG.

Since a line voltage corresponding to FIG. 2 is also generated between the lines on the secondary side of the transformer 71, it is rectified by the rectifier 72 to obtain a DC voltage. Since the value of this DC voltage fluctuates depending on the overhead line voltage and is not stable, it is stabilized through a converter such as 73.

〔Effect of the invention〕

As described above, in the vehicle auxiliary power supply circuit according to the present invention, since the auxiliary power supply converter is connected to the secondary side of the transformer, the semiconductor element used in the converter and its withstand voltage can be freely selected. Since it is possible to use low-cost elements that are most suitable for the auxiliary power supply device, it is possible to significantly reduce the cost, size, and weight of the auxiliary power supply device.

Furthermore, since only a transformer with high reliability is connected to the main circuit side, the reliability of the main circuit and the auxiliary power system as a whole is greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of a vehicle auxiliary power supply circuit according to the present invention, FIG. 2 is an operation waveform diagram for explaining the embodiment of the present invention, and FIG. 3 is a circuit diagram showing a conventional example. FIG. 4 is a circuit diagram showing details of a conventional auxiliary power supply device. 1...Cooler 2-phase PWM inverter 3
...Telephone line 4...Starting device 5...Smoothing capacitor 6...Auxiliary power supply device 61...Auxiliary PWM inverter 62...Isolation transformer 63...Rectifier 7...
- Auxiliary power supply device 71... Transformer 72... Rectifier 73... Converter 81, 82... Auxiliary power output

Claims (1)

[Claims] PWM from DC power source supplied from overhead contact line or third rail
A vehicle auxiliary power supply circuit in a DC electric vehicle that supplies power to an AC load via an inverter, wherein the auxiliary power supply circuit obtains power from the AC output of the PWM inverter via a transformer. power circuit.