KR100511644B1 - Parallel dc voltage supply system for recycled electric train cope - Google Patents

Abstract

The present invention relates to a parallel DC voltage power supply system corresponding to a regenerative electric vehicle free of stable supply and regeneration by supplying the DC power supplied to the vehicle in a rectifying method and supplying regenerative power to the power supply through a converter during vehicle regeneration.

The present invention requires a system configuration to effectively use the regenerative energy as a power supply system in accordance with the introduction of the regenerative vehicle and to reduce the regenerative effectiveness. In the present invention, the main point is to supply DC power to the vehicle by rectification method, and when the vehicle is regenerated, the regenerative power is supplied to the power supply through the converter so that the stable supply and regeneration can be made free. Is characterized by a method of controlling so that it can be regenerated by a power source.

Description

Parallel DC voltage supply system corresponding to regenerative electric vehicle {PARALLEL DC VOLTAGE SUPPLY SYSTEM FOR RECYCLED ELECTRIC TRAIN COPE}

The present invention relates to a parallel DC voltage feeding system corresponding to a regenerative electric vehicle, and more particularly, to supply a DC power to the vehicle in a rectifying method, and to supply the regenerative power to the power supply through a converter when the vehicle is regenerated, providing a stable supply and regenerative power. A parallel DC voltage power supply system corresponding to this free regenerative electric vehicle.

In order to supply power to an electric vehicle, AC power is generally supplied to an electric vehicle feeder using a transformer and a three-phase bridge rectifier circuit. The rectifier circuit converting to direct current was first used with a 6-pulse rectifier and then a 12-pulse rectifier.

In general, a method commonly used for power supply of electric cars uses a method of supplying only a rectifier. In this case, problems arise due to voltage increase when the vehicle is regenerating or decelerating the speed, and since a plurality of vehicles are repeatedly reversing and regenerating in the power supply section, a lot of ripple due to the rectifying supply method is included, and severe load fluctuations are caused. Therefore, when the line voltage fluctuation is large and the separation distance between the vehicle and the vehicle is close, the voltage fluctuation is large and the protection device of the vehicle is operated to cause the vehicle to stop momentarily.

In order to compensate for the current problem, by supplying electric vehicle power supply system in parallel with rectification method and converter method, it plays a role to compensate for insufficient voltage of the electric line or rising voltage when regenerating electric motor through PWM inverter. A smooth power supply is required.

Therefore, the present invention is to solve the above-mentioned conventional problems, the object is to supply the power supply method using the rectification method and the PWM converter device when the voltage drop of the line voltage, to the regeneration of the vehicle When the voltage rises, a regenerative power converter is used to provide a parallel DC voltage feed system for regenerative electric vehicles that can reduce harmonics and control regenerative power with high efficiency while regenerating excess DC power in an AC bus. have.

In order to achieve the above object, the present invention has been directed to a control method of supplying power by performing a forward conversion and a reverse conversion of a high power factor using a PWM converter. Voltage-type PWM converters are structured to be coupled to an AC power source with a reactance between them.

The converter having such a structure allows an AC current close to a sinusoidal wave containing less harmonics, and has a characteristic that the DC side voltage increases in inverse proportion to the modulation rate. The no-load voltage converter has the function of a reactive power generator that improves the power factor of an AC power supply, and is used as a means of voltage adjustment by applying to a power system requiring compensation of reactive power. The application to AC / DC converters has the capability of high power forward and reverse conversion with zero reactive power.

The present invention maintains the DC voltage at a constant voltage by using a rectifier and a converter device, and improves energy efficiency by using a converter at the time of regeneration.

PWM modulation uses a method of reducing harmonics from the AC power supply and consists of an AC / DC converter with the function of supplying and regenerating power.

In order to reduce harmonics during power supply, the phase of the power converter can be changed to remove harmonics, thereby providing more safe power.

The converter is preferably operated under conditions that can effectively use the equipment capacity of the transformer or the like installed in the power supply. In contrast, the converter preferably operates at a power factor of 1 that maintains the voltage and current of the power supply in phase, and in this case, the converter is economically operated to minimize the loss of the line. In addition, the converter itself has the least current flowing in each device with respect to the conversion capacity, making it an ideal operation method that uses the power semiconductor device most effectively.

Fig. 1A is an equivalent circuit of a converter, which is an equivalent circuit of a power supply and a converter when the power supply voltage is V and the AC side voltage of the converter is E.

In FIG. 1A, when the current I flowing through the converter is kept in phase with the power supply V, the power supply voltage and the current vector may be represented by a vector as shown in FIG. 2.

In the vector diagram of FIG. 1B, the subscript f is a case of forward transformation, and the subscript r is an inverse transformation operation state. In this case, the voltage drop of the AC reactor between the power supply and the converter shown in FIG. 1B maintains a phase difference of 90 degrees with the power supply. It works. Therefore, the AC side voltage E of the converter must maintain the voltage vector minus the reactor voltage. In other words, the vector diagram should always be maintained at right angles to the triangle.

The AC current is determined by the voltage between the reactor and the reactor, and the reactor voltage is the difference between the AC voltage and the AC voltage of the converter, so the AC current can be controlled by the PWM modulation rate of the converter, the phase of the modulated wave, and the DC voltage.

Equation 1 is obtained from the equivalent circuit of FIG. 1A and the vector diagram of FIG. 1B, resulting in Equation 2.

Here, α is the phase difference between V and E, and the converted power of the converter is the input power on the AC side, so that Equation 3 is obtained.

If Equation 2 and Equation 3 are arranged, Equation 4 is established.

Equation 4 represents the conversion power of the converter, and considering the equation 2 Equation 3, it can be seen that the conversion capacity is determined by the magnitude of the inductance and the phase angle α of the AC reactor.

Figure 2 shows the overall circuit configuration of supplying electric vehicle power using the voltage supply and the power regenerative circuit using the threshold and converter parallel method according to the present invention. Here, the threshold and PWM inverters each have a three phase voltage type (VSI) power converter which converts an AC voltage into a DC voltage.

As shown in Figure 2, the operation of this method is as follows.

1) During retrograde, voltage is supplied to the vehicle through power supply transformer, rectifier and filter.

2) When the vehicle is regenerating, it is supplied with electric power through inverter, inverter transformer and power transformer through DC filter.

Here, the inverter output voltage is DC1500V, and the rectifier also supplies DC1500V.

3) When supplying voltage in parallel, harmonics can be reduced and reliability can be maintained by supplying power in double in case of breakdown.

3 is a block diagram illustrating a parallel DC voltage power supply system corresponding to a regenerative electric vehicle according to the present invention.

4 illustrates a regenerative inverter (PWM CONVERTER) in which an AC side maintains a high power factor by using a PWM converter for supplying regenerative power. An alternating voltage is input as an input voltage and changed to a desired DC voltage, thereby providing a voltage to a vehicle. The DC voltage used in the car wire is changed to AC power 60Hz through the inverter during regeneration and is supplied to the power supply.

5 is related to a six-phase rectifier circuit device, which rectifies the input AC voltage into a DC voltage and supplies the vehicle with a DC 750V voltage. However, the device supplies power only and can be regenerated by a power source. There is no problem.

FIG. 6 is a modeling block diagram for simulating an operating situation when a PWM converter has a variable control angle in parallel operation. FIG. 6 is a modeling circuit for simulating whether or not an inverter (PWM CONVERTER) can be supplied and regenerated. Is a block diagram of.

Fig. 7 is a graph showing the results of simulating the operating conditions when the line voltage rises in parallel operation of the PWM converter. The results also show good voltage and current output characteristics.

That is, even if the line voltage fluctuates during regeneration, the voltage and current are well supplied without change.

As described above, according to the present exemplary embodiment, the constant voltage required for the tramline can be maintained by supplying a voltage using the stop value and the PWM converter in parallel. The rectifier is supplied with voltage, and the converter device is used with voltage supply and regenerative to achieve stable stabilization of the wire. Also, it can save energy in terms of operating the electric car and supply high-quality power to the vehicle. It can be improved, and the interval between substations can be increased, so that the number of substations can be reduced, so it is economical, and the vehicle operation time can be reduced, and the operation maintenance cost of the vehicle operator can be reduced.

1A is an equivalent circuit of a converter.

FIG. 1B is a vector diagram of FIG. 1A

2 is a circuit diagram of an electric vehicle power supply and a power regenerative circuit using a rectifier and a PWM inverter according to the present invention.

3 is a block diagram of the present invention.

4 is a PWM inverter for returning DC regenerative power to a power supply.

5 is a DC rectifier circuit.

6 is a simulation circuit.

7 is a graph showing simulation results of inverter operation when the DC voltage rises (vehicle regeneration).

Claims (3)

First and second transformers connected in parallel to each other and configured to output AC voltages supplied from a voltage supply unit to a predetermined level; A stop value for rectifying the AC voltage supplied from the first transformer to supply a DC voltage to a feed line; And Converting an AC voltage supplied from the second transformer into a DC voltage and outputting the DC voltage to the power supply line, and converting a DC voltage raised from the power supply line into an AC voltage by regenerative energy during electric vehicle regeneration or speed reduction, thereby generating a regenerative voltage. PWM inverter Parallel DC voltage supply system corresponding to the regenerative electric vehicle comprising a. delete The method of claim 1, And said stop value and said PWM converter respectively correspond to a regenerative electric vehicle having a three-phase voltage type (VSI) power converter for converting an AC voltage into a DC voltage.