KR100491864B1 - dirct current(D.C)power supply system used of revivable 2-level PWM converter, for electromotive car - Google Patents

Abstract

The present invention relates to an electric vehicle DC power supply system using a regenerative two-level feeder UEM converter;

Its purpose is to use the regenerative two-level F / M converter for regenerating the excess DC power generated during operation of the electric vehicle to the AC bus, reducing harmonics, and controlling the regenerated power with high efficiency. It is to provide a DC power supply system for electric cars, and another purpose is to provide a stable voltage supply by a regenerative two-level converter, to reduce the separation distance between the electric vehicles and to increase the safety of the electric vehicle operation. At the same time, the remaining power in the regeneration is to provide a direct current (DC) power supply system for the electric vehicle using a regenerative two-level FEM converter that can be reduced to the power source to perform a useful energy utilization function.

Therefore, the specific means of the present invention for achieving the above object;

Electric vehicle DC consisting of a three-phase AC power supply as a power supply means, a transformer as a voltage control means, a rectifier for acquiring DC power from AC power, a circuit breaker as an opening / closing means for an electric circuit, and a feeder line for supplying electric power to an electric vehicle. A power supply system;

The rectifier is achieved by supplying and regenerating an AC power supplied to a power source of an electric vehicle by DC power by constructing a two-level FEM (PWM) converter having a high power factor forward conversion and an inverse conversion function. .

Description

Power supply system used of revivable 2-level PWM converter, for electromotive car}

The present invention relates to a DC power supply system for an electric vehicle using a regenerative two-level dual PWM (PWM) converter, and more particularly, as a stable voltage supply action by a regenerative two-level converter, The present invention relates to an electric vehicle DC power supply system using a regenerative two-level power converter that reduces power, increases safety due to the operation of an electric vehicle, and at the same time, allows the remaining power to be restored to a power source to perform a useful energy utilization function. .

Conventional electric vehicle DC power supply systems (such as a chopper device or inverter method), which are widely used in general, rectify three-phase AC power as a feed system into DC power, and convert the rectified DC power into a power supply line. Will be made by supplying to the electric vehicle through;

Therefore, when the electric vehicle is regenerative braking, when it arrives at the station or when driving downhill, the voltage of the DC bus is increased by the regenerated energy.

However, the regenerated energy increases only a limited voltage in the power supply system of the electric vehicle and does not regenerate the remaining energy. When the energy is not consumed by another electric vehicle, the voltage of the DC bus continues to increase and the voltage of the electric vehicle system is increased. It would have a bad effect on various devices.

In addition, the general regenerative electric vehicle is to generate the regenerative energy when the speed is suppressed due to the operation of the regular or downward gradient section, but the conventional electric vehicle system is configured to convert three-phase alternating current into direct current by the rectifier. In the absence of a retrograde vehicle using regenerative power, the regenerative electric vehicle loses the regenerative effect and causes a problem of switching from the regenerative brake to the air brake.

Therefore, the effective use of the regenerative energy as a power supply system according to the introduction of the regenerative electric vehicle, and the development of a system configuration for reducing the regenerative effectiveness remains an urgent task.

Meanwhile. Alternatively, the general rectification method of electric vehicle power supply system. As shown in FIG. 1, a three-phase power source, a transformer, a rectifier, a circuit breaker, and a feeder line are adopted. The alternating current (AC) power supplied to a power source of an electric vehicle is transferred by a transformer and a three-phase bridge rectifier circuit. DC) to be converted into electric power, thereby supplying it to the feeder of the electric vehicle;

At this time, in converting AC into direct current, the rectifier circuit was initially adapted to adopt a 6-pulse rectifier and then a 12-pulse rectifier.

However, the conventional six-pulse rectifier system used for power supply of the electric vehicle usually includes a lot of ripple in direct current (DC) power. This is because when the separation distance between the running vehicle and the electric vehicle is close, the voltage change is increased to operate the protection device of the electric vehicle, and the operation of the electric vehicle protection device such as the operation of stopping the motor vehicle in operation as a problem. Giving;

In addition, the conventional 12-pulse rectifier method used for power supply of the electric vehicle can reduce the ripple to some extent compared to the above-mentioned 6-pulse rectifier method, but when the speed of the driving vehicle is close, the electric vehicle is still increased by increasing the voltage fluctuation. To reduce the reliability of the system, and to cause significant vehicle driving problems that voltage regeneration is also impossible.

On the other hand, as a supplement to the problems of the conventional rectification method generated when supplying power to the electric vehicle, in recent years, a power supply method using a silicon controlled rectifier (SCR) has also been used.

However, the power feeding method using the silicon-controlled rectifier does not perform constant voltage control and perfect regenerative control due to the limitations of the power semiconductor element, and generates considerable harmonics, which adversely affects the reliability of the electronic device. In the operation of electric vehicles, the problem of very inefficiency remained.

Therefore, the present invention was devised to solve the general problems of the conventional rectification method generated in supplying power to the electric vehicle;

An object of the present invention is to regenerate the excess DC power generated during the operation of the electric vehicle to the AC bus and at the same time to reduce the harmonics, and to control the regenerative power with high efficiency, the regeneration two-level FEM converter It is to provide a DC power supply system using an electric vehicle.

On the other hand, another object of the present invention is to provide a stable voltage supply by the regenerative two-level converter, to reduce the separation distance between the electric vehicle, to increase the safety of the operation of the electric vehicle, while at the same time the power remaining in the regeneration It is to provide a direct current (DC) power supply system for an electric vehicle using a regenerative two-level feeder UEM converter capable of performing a useful energy utilization function to be reduced.

Thus, the specific means of the present invention for achieving the above object;

 Electric vehicle DC consisting of a three-phase AC power supply as a power supply means, a transformer as a voltage control means, a rectifier for acquiring DC power from AC power, a circuit breaker as an opening / closing means for an electric circuit, and a feeder line for supplying electric power to an electric vehicle. A power supply system;

The rectifier is achieved by supplying and regenerating an AC power supplied to a power source of an electric vehicle by DC power by constructing a two-level PWM (PWM) converter having a high power factor forward conversion and an inverse conversion function. .

Hereinafter, a preferred embodiment of an electric vehicle DC power supply system using a regenerative two-level FEM converter according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a comparative configuration diagram of a conventional DC power supply system and a DC power supply system according to the present invention, Figure 2 is a circuit of a DC power supply system for an electric vehicle using a regenerative two-level PWM converter according to the present invention. 3 is an equivalent circuit diagram of a two-level FWM converter applied to the present invention, and FIG. 4 is a vector diagram of a two-level FWM converter applied to the present invention.

 It supplies power to three-phase AC power supply as a power supply means, a transformer as a voltage control means, a two-level PWM converter for obtaining DC power from AC power, a circuit breaker as an opening and closing means of an electric circuit, and an electric vehicle. It is configured by interconnecting feeders.

At this time, the three-phase AC power source is a conventional energy supply source for driving the electric vehicle, such a three-phase AC power source to take the general configuration to generate electric energy by driving the generator, so that it is transmitted to the electric vehicle. will be.

In addition, the transformer is a conventional stop device that receives the AC power from the above-described three-phase AC power source to supply power to other circuits by an electromagnetic induction action, which is shown in FIG. 2 when applying such a transformer to the present invention. It is desirable to be provided with a power supply transformer and a converter transformer as shown.

In addition, the two-level PWM converter is a control method for supplying power by forward and inverse conversion of the used power to a high power factor, such a two-level PWM converter is shown in FIG. As described above, it is preferable to take a structure in which a reactor is interposed therebetween and connected to an AC power source.

In this case, the two-level PWM converter having the structure as described above has a characteristic of flowing an AC current close to a sine wave containing less harmonics and increasing the DC voltage in inverse proportion to the modulation rate. 2 level PWM converter is a function of reactive power generator that improves the power factor of AC power. It is used as a means of voltage adjustment by applying to power system that needs compensation of reactive power, and also AC / DC converter In this case, the reactive power is set to 0 to have high power factor forward and reverse power.

In addition, the breaker is a means for controlling the power supplied for the operation of the electric vehicle as necessary, such a breaker has a conventional configuration to change the opening and closing of the electric circuit or the connection state.

In addition, the feed line is a means for supplying the power required for the operation of the railway vehicle, such a feed line is formed of a wire (coupling line) structure is installed in parallel with the tram line as shown in Figure 1 for supplying power from the substation. It is.

Therefore, the regenerative two-level PWM converter according to the present invention comprising the three-phase AC power supply, a transformer, a two-level PWM converter, a circuit breaker, and a power supply line. The electric vehicle DC power supply system using;

When the AC power is supplied through the first three-phase AC power, the AC power supplied through the transformer is converted into an AC voltage suitable for the system of the present invention by electromagnetic induction, and the AC voltage thus converted is It is converted into DC voltage by 2 level PWM converter, which is the main structure, and selectively selects DC (1500V) DC and DC (750) 750V power required for electric vehicle operation through feeder line as a circuit breaker by circuit breaker. Will be supplied.

At this time, the two-level PWM converter applied to the present invention is operated under conditions that can be effectively used for the facility capacity of the transformer installed in the three-phase AC power source. The WM converter maintains the operation state of the power factor 1 which maintains the voltage and current of the three-phase AC power source in phase, thereby enabling economical operation to minimize the loss of the line and the like.

In addition, the two-level feed-through converter (PWM) by itself maintains the minimum current value flowing to each device with respect to the conversion capacity to provide an ideal operation method that uses the power semiconductor device most effectively.

That is, look at this in more detail;

FIG. 3 is an equivalent circuit diagram of a two-level PWM converter according to the present invention. When the power supply voltage is V and the AC side voltage of the two-level PWM converter is E, PWM) When the current I flowing through the converter is kept in phase with the power supply voltage V, the power supply voltage and the current vector can be represented as a vector diagram as shown in FIG.

At this time, in the vector diagram of FIG. 4, the subscript f represents the case of the forward transformation, and the subscript r represents the inverse transformation operation state. In this case, as shown in FIG. 4, the voltage drop of the AC reactor between the power supply and the two-level PWM converter maintains a phase difference of 90 ° from the power supply, and when the voltage phase of the reactor is 90 ° ahead of the power supply. In the case of the forward transformation, if it is 90 degrees, the reverse transformation is performed.

Therefore, the AC side voltage E of the two-level PWM converter must maintain a voltage vector subtracted from the reactor voltage. In other words, the vector diagram should always be maintained as a right triangle.

In addition, 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 side voltage of the two-level PPM converter, so that the AC current is the PWM modulation rate of the converter. It can be controlled by the phase and the DC voltage of the modulated wave.

    In addition, from the equivalent circuit of the two-level PWM converter of FIG. 3 and the vector diagram of the two-level PWM converter of FIG.

Because of

To be. In this case, α is the phase difference between V and E, and the conversion power of the two-level PWM converter is the input power at the AC side.

It will be.

In addition, summarizing the above formulas (1-2) and (1-3) is that the following formula (1-4) is established

Therefore, Equation (1-4) represents the conversion power of the two-level PWM converter. Considering Equation (1-2) and Equation (1-3), the conversion capacity is the value of the AC reactor. It can be seen that it is determined by the magnitude of the inductance and the phase angle α.

On the other hand, Figure 5 is a circuit diagram showing another embodiment of the present invention, the present invention as yet another embodiment of the present invention is to be provided with a plurality of two-level PWM (PWM) converter, and then each two-level PWM (PWM) ) The DC side of the converter is operated in series with each other to obtain high efficiency, and the AC side is to maintain high power factor.

Thus, as another embodiment of the present invention, as shown in FIG. 5, two FDM converter structures including an insulated gate weak polar transistor (IGBT) are shown. In order to obtain a high DC voltage, the DC side is connected in series, and the AC side of each FWM converter is connected to each other with three reactors interposed therebetween.

 At this time, the AC side grounds one pole of the DC side so that the two PWM converters are insulated from the AC power source by a transformer.

In addition, in order to reduce the harmonic content of the current waveform flowing through the power supply, the modulation carrier of each of the PWM converters is subjected to the PWM modulation having a phase of 90 degrees.

FIG. 6 is a diagram illustrating modulation of any two phases in the two PWM converters described above. Thus, the two PWM converters convert the modulated waveforms of the phase voltages by 90 degrees. Although the phase voltage waveform is used as the phase difference, it is possible to predict that the waveform of the AC current is improved since the pulse voltage exists at the position where the two PWM converters compensate the mutual waveform.

In the above, the electric vehicle DC power supply system using the regenerative two-level PWM converter according to the present invention allows the excess DC power generated during the operation of the electric vehicle to be regenerated by an AC bus, and at the same time, reduces harmonics. To control the regenerative power with high efficiency;

In addition, as a stable voltage supply action by the level converter, it is possible to reduce the separation distance between the electric vehicles, increase the safety according to the operation of the electric vehicles, and at the same time, the remaining power during regeneration is reduced to the power source to perform useful energy utilization functions. It would provide very useful expectations at the national level.

1 is a comparative configuration of a conventional DC power supply system and a DC power supply system according to the present invention

2 is a circuit configuration diagram of a DC power supply system for an electric vehicle using a regenerative two-level FMB converter according to the present invention.

FIG. 3 is an equivalent circuit diagram of a two-level dual PWM converter according to the present invention.

FIG. 4 is a vector diagram of a two-level flexible PWM converter according to the present invention.

Figure 5 is a circuit diagram showing another embodiment of the present invention

6 is a modulation state diagram of a PWM converter according to the present invention;

7 is a driving circuit diagram using another embodiment configuration of the present invention.

8 is a circuit diagram illustrating a voltage supply circuit for transformers in front of a PWM converter according to the present invention.

9 is a simulation result of the operating situation according to the present invention

Claims (3)

 Electric vehicle DC consisting of a three-phase AC power supply as a power supply means, a transformer as a voltage regulating means, a rectifier for acquiring DC power from AC power, a circuit breaker as an opening / closing means for an electric circuit, and a feeder for supplying electric power to an electric vehicle. A power supply system; The rectifier is composed of a two-level dual PWM (PWM: pulse width modulation) converter having a high power factor forward conversion and an inverse conversion function, and supplies AC power supplied to a power source of an electric vehicle to DC power. Electric vehicle DC power supply system using a regenerative two-level feeder U (PWM) converter, characterized in that the regeneration. delete delete