JPH06197402A - Controller for ac electric rolling stock - Google Patents

Abstract

PURPOSE:To prevent a power balance state of a power drive electric rolling stock and a regenerative electric rolling stock in the same power supply section and to detect power interruption by advancing a secondary current pattern at the time of regenerating at least to a control deviation or more, and so controlling that an actual secondary current becomes a specific phase angle or more lead angle. CONSTITUTION:An output of a current regulator 24 is compared with a secondary winding voltage Vs of a transformer 3 by an adder 25, its output is input to a PWM circuit 26 to be controlled. When power interruption occurs, a phase of the voltage Vs is varied, and hence the phase angle of the actual secondary current Is is so controlled thereto that a phase angle is advanced to 180 deg. or more to the AC power source voltage Es. Then, since a period of a zero-cross remains short, an output of a period detector 40 is continued in a state exceeding a range of a comparator 41, and the comparator 41 outputs a power failure detection signal. The detection signal is inputted to PWM circuits 26, 27 to stop operations of a pulse width modulation converter 5 and a pulse width modulation inverter 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an AC electric vehicle having a pulse width modulation converter circuit as a main circuit and having an AC power regeneration function, and more particularly to a function for detecting a power failure of an AC power source. The present invention relates to a control device for an AC electric vehicle.

[0002]

2. Description of the Related Art As a method for detecting a power failure of an overhead line of an AC electric vehicle, a DC stage voltage (voltage across a smoothing capacitor) has been disclosed in Japanese Patent Laid-Open No. 1-248968.
There was a device that monitors the power supply and sends out a power failure detection signal when it is within the scheduled conditions.

Also, Japanese Patent Laid-Open No. 1-252173 detects a power failure by utilizing the fact that the phase difference between the secondary winding voltage and the secondary current of a transformer automatically becomes 180 ° during a power failure. was there.

[0004]

However, the former case of the above-mentioned prior art does not consider the case where a regenerative vehicle exists in the same feeding section.

Further, in the latter case, the secondary current pattern Isp is set so that the power factor becomes −1, that is, φ becomes 180 ° during the regenerative operation. Therefore, when there is a control deviation, the actual secondary current is present. Is is the secondary current pattern Isp
The phase is delayed compared to. The actual secondary current Is is 2
The reason why the phase is delayed compared to the next current pattern Isp will be described below.

In order to perform the regenerative operation, the regenerative current does not flow unless the converter input voltage Vc leads the transformer secondary winding voltage Vs in phase. Therefore, as shown in FIG.
There is always a phase difference between c and Vs, and they are never in phase. Therefore, since the Vs-ACR output is Vc,
ACR output is always present.

ACR output divided by ACR gain G gives A
It becomes CR input εIs. Strictly speaking, since the ACR itself has a delay element, the phase is slightly converted, but since it is negligible, the ACR input εIs may be considered to be in phase with the ACR output. Further, the gain G of the ACR has a finite value in order to stably operate the control system. Therefore, the deviation εIs always exists.

Since Isp-Is = εIs, Is and I
The relationship of sp is as shown in FIG. 6, and the actual secondary current Is
Is delayed in phase as compared with the secondary current pattern Isp. First, it is assumed that the main circuit system of the electric vehicle A that is performing power running is a resistance control vehicle or a phase control vehicle. In this case, the equivalent circuit of the electric vehicle A can be represented by a series circuit with a pure resistance load component and an inductive load component. An equivalent circuit diagram at this time is shown in FIG.

In the conventional control method, the I supplied by the regenerative vehicle is supplied.
Voltage drop V due to pure resistance load on the power vehicle side due to s
A voltage drop V1 'occurs due to r'and the inductive load.
When the vector diagram becomes as shown in FIG. 4 depending on the operating state, it becomes equal to the transformer secondary winding voltage Vs before the power failure.

At this time, the voltage drop V due to the pure resistance load
With respect to the transformer secondary winding voltage Vs resulting from the combination of r ′ and the voltage drop V1 ′ due to the inductive load, the secondary current pattern Isp is generated again. It continues to look like there is no power outage.

Even if the electric power generated on the regeneration side decreases due to deceleration, if the power running electric vehicle is a resistance control vehicle or a phase control vehicle,
Since the power consumption on the power running side also decreases due to the drop in the overhead line voltage, this vector diagram remains similar,
The balance will continue.

When this balance state continues, in the case of the method of detecting the power failure by detecting the fluctuation of the DC stage voltage, there is a problem that it is difficult to detect the power failure because the DC stage voltage does not change.

Also, when the power is cut off, the phase difference is automatically φ = 18.
In the method of detecting by utilizing the fact that the angle becomes 0 °, when the balance state as shown in FIG. 4 occurs, φ
Since the angle is not 180 °, there is a problem that detection is difficult.

In any case, in the above prior art, when there is a power running electric vehicle and a regenerative electric vehicle in the same power feeding section and when a power failure occurs at the substation, the power running electric vehicle and the regenerative electric vehicle are connected between the power running electric vehicle and the regenerative electric vehicle. When a power balance occurred, there was a problem that the power failure could not be detected promptly.

It is an object of the present invention to provide a control device for an AC electric vehicle that can reliably detect a power failure even under conditions where it is difficult to detect a power failure.

[0016]

The present invention has taken the following means in order to solve the above problems and achieve the object. That is, in order to prevent the present invention from falling into a balanced state,
By advancing the secondary current pattern Isp during regeneration by at least the control deviation or more (when the power train A is an inductive load), the actual phase angle of the secondary current Is is 180 ° or more. It is controlled so that the lead angle is set.

[0017]

In the control method according to the present invention, the secondary current pattern Isp is controlled so as to advance by at least the control deviation or more (when the power running electric vehicle is an inductive load).

Consider a case where a power failure occurs in a substation when the regenerative electric vehicle B shown in FIG. 7 is installed and operated with a control device for an AC electric vehicle that employs this control method. FIG. 8 shows an instantaneous waveform chart of each part. Since the AC power supply voltage Es is predominant before the occurrence of a power failure, the phase of the transformer secondary winding voltage is dominated by the AC power supply voltage Es. When a power failure occurs, the actual secondary current Is generated by the regenerative train B causes a voltage drop Vr ′ due to the pure resistance load of the power running electric vehicle A.
A transformer secondary winding voltage Vs, which is a combination of the voltage drop Vl ′ due to the inductive load component, is generated. At this time, since the actual secondary current Is is controlled so that φ advances by 180 ° or more with respect to the AC power supply voltage Es,
The transformer secondary winding voltage Vs obtained by combining the voltage drop Vr 'due to the pure resistance load component of the power train A and the voltage drop Vl' due to the inductive load component is at least a voltage due to the inductive load component with respect to the AC power supply voltage Es. It will advance by the amount of the drop Vl '. Therefore, during a power failure, the phase of the transformer secondary winding voltage Vs changes.

When the AC power source fails during the operation of the pulse width modulation converter, the phase relationship changes as described above, and the zero-cross cycle changes. As a result, the power failure detection device outputs a power failure detection signal. Therefore, it becomes possible to immediately stop the operation of the pulse width modulation converter and the pulse width modulation inverter using this signal.

If the regenerative electric vehicle B detects a power failure, it is possible to take necessary measures such as stopping the operation of the pulse width modulation converter and the pulse width modulation inverter and quickly stopping the electric vehicle by a mechanical brake or the like. it can. Further, since the power running electric vehicle A is also cut off from the energy, it is possible to detect a power failure and similarly take necessary measures.

[0021]

FIG. 10 is a diagram showing an embodiment of a control device for an AC electric vehicle to which the present invention is applied.

The AC power supplied from the AC power supply 11 to the overhead line 1 at the substation is received by the electric vehicle by the pantograph 2. This AC power is supplied to the pulse width modulation converter main body 5 via the transformer 3 and the reactor 4 using the leakage inductance of the transformer, converted into DC power by the pulse width modulation converter main body 5, and at the smoothing capacitor 6. It is smoothed and supplied to the pulse width modulation inverter 7. The AC motor 8 is driven by the pulse width modulation inverter 7.

The pulse width modulation converter main body 5 performs an AC → DC conversion (forward conversion) operation during a power running operation of an electric vehicle, and a DC → AC conversion (reverse conversion) operation during a regenerative operation. During both operations, the pulse-width modulation converter main body 5 generally keeps the voltage Vd across the smoothing capacitor 6 at a constant value, and the secondary winding voltage Vs of the transformer 3 and the secondary current Is of the transformer 3. Controls the power factor cosφ determined by the phase difference φ of. The power factor is usually controlled so that the maximum value cos φ = ± 1, that is, φ is 0 ° or 180 °. Figure 2
FIG. 6 is a vector diagram of a voltage and a current Is of an AC circuit when the pulse width modulation converter main body 5 is operated such that a power factor is 1, that is, φ = 0 ° during a power running operation. Figure 3
Has a power factor of -1 during regenerative operation, that is, φ is 180 °
FIG. 7 is a vector diagram of a voltage and a current Is of an AC circuit when the pulse width modulation converter main body 5 is operated so that

The AC electric vehicle using the pulse width modulation converter has the following problems. That is, since the pulse width modulation converter uses the self-extinguishing capability element, it can operate even during a power failure. Therefore, if there is a power running electric vehicle and a regenerative electric vehicle in the same power supply section and a power outage occurs, energy will be transferred between the two electric vehicles, and there is a risk of traveling without knowing the power outage at the substation. There is.

As shown in FIG. 7, there are two electric cars A and B in the section for supplying overhead line power from the same substation (hereinafter referred to as the same section), and the electric car B is the system shown in FIG. When electric vehicle A is performing powering operation when the vehicle is in a state of supplying power from electric vehicle B to electric vehicle A even when the overhead line has a power failure, that is, when the substation interrupts power transmission. Driving may continue, but it is necessary to avoid this situation for security reasons. This is a particularly important issue for railways that employ a system that stops electric vehicles by causing a power outage from overhead lines in the event of an abnormality in ground equipment such as an earthquake.

Embodiments will be described below with reference to the drawings. FIG. 1 is an example of a circuit diagram of an electric vehicle equipped with an AC electric vehicle control device adopting a control method according to an embodiment of the present invention.

The AC power supplied from the AC power supply 11 to the overhead line 1 at the substation is received by the electric vehicle via the pantograph 2. This AC power is supplied to the pulse width modulation converter main body 5 composed of the self-extinguishing capability element via the transformer 3 and the reactor 4 utilizing the leakage inductance of the transformer, and is converted into DC power by the pulse width modulation converter. It is smoothed by the smoothing capacitor 6 and supplied to the pulse width modulation inverter 7. The AC motor 8 is driven by the pulse width modulation inverter 7. The pulse width modulation converter main body 5 performs an AC → DC conversion (forward conversion) operation during a power running operation, and performs a DC → AC conversion (reverse conversion) operation during a regenerative operation. During both operations, the pulse-width modulation converter body 5 generally has a smoothing capacitor 6
The voltage Vd at both ends of the
power factor determined by the phase difference φ between s and the secondary current Is of the transformer 3
The AC input voltage Vc is controlled so that cosφ is maintained at a high value.

The voltage Ep of the transformer 3 is introduced through a synchronous power supply filter 30 installed for the purpose of removing noise and harmonics contained in the power supply, and a zero-cross detector 31 obtains a zero-cross pulse. The cycle of the zero-cross pulse is measured by the cycle detector 40, and the comparator 41 compares it with the set value. If the difference between the cycle of the zero-cross pulse and the set value exceeds a certain fixed range, the power failure detection signal is set to PW.
It outputs to the M circuits 26 and 27.

The counter 33, which counts the clock signal and is reset by the zero-cross pulse, determines the address of the sine wave ROM.
An offset is added to the address by adding the output of the phase setting device 37 to the output of the counter 33 by the adder 34 in order to change the phase of sp. By giving the address to which this offset is added to the sine wave ROM 35, sine wave digital data can be obtained. The digital output signal of the sine wave ROM is input to the D / A converter 36 and converted into an analog signal. However, if digital control is used, D
The / A converter 36 is unnecessary.

The target value Vdp of the DC voltage and the measured value Vd are compared by the adder 20, and the difference is compared with the AVR (voltage regulator) 21.
To enter. The output of this AVR (voltage regulator) 21,
A secondary current pattern Isp is obtained by multiplying the digital output signal of the sine wave ROM 35 converted to an analog signal by the multiplier 22.

The secondary current pattern Isp and the output of the current transformer 9 are compared by the adder 23, and the result is input to the ACR (current regulator) 24. The adder 25 compares the output of the ACR (current regulator) 24 with the secondary winding voltage Vs of the transformer 3 and inputs the output to the PWM circuit 26 to obtain a predetermined gate signal.

FIG. 8 shows an instantaneous waveform diagram of the voltage / current of each part during a power failure. When a power failure occurs, first, the phase of the transformer secondary winding voltage Vs changes. This is because the AC power supply voltage Es is normally dominant and the transformer secondary winding voltage Vs is also dominated by the AC power supply voltage Es. However, due to a power failure, the voltage drop due to the pure resistance load of the power running electric vehicle is caused. This is because the transformer secondary winding voltage Vs is generated by the combination of Vr ′ and the voltage drop Vl ′ due to the inductive load.

At this time, in the present control method, the actual secondary current Is
Since the phase angle of is controlled so that φ is 180 ° or more with respect to the AC power supply voltage Es,
The phase of Vs is advanced by at least the voltage drop Vl 'due to the inductive load before the power failure.

As a result, the zero-cross period becomes short, and 2
The next current pattern Isp changes. The actual secondary current Is flows to this secondary current pattern Isp, and the transformer secondary winding voltage Vs generated by the combination of the voltage drop Vr ′ due to the pure resistance load and the voltage drop Vl ′ due to the inductive load is again generated. Occur.

Therefore, the zero-cross cycle remains short, and the output of the cycle detector 40 continues to exceed the range of the comparator 41. At this time, from the comparator 41,
A power failure detection signal is output.

This power failure detection signal is input to the pulse width modulation circuits 26 and 27, and the operation of the pulse width modulation converter and the pulse width modulation inverter is stopped.

With such a configuration, as shown in FIG. 7, there are a power running electric vehicle A and a regenerative electric vehicle B in the same power feeding section, a power failure occurs at the substation C, and power feeding is stopped. As described above, since the phase of the transformer secondary voltage Vs changes and the zero-cross cycle changes, the power failure detection signal is output from the comparator 41. Therefore, the operation of the pulse width modulation converter main body 5 and the pulse width modulation inverter main body 7 on the regenerative electric vehicle B side is stopped. Further, since the power supply of the power running electric vehicle A is completely cut off, the power failure can be detected by the operation of the normal detection system.

[0038]

According to the present invention, there is a power outage under a condition that is difficult to detect by the conventional method, for example, a power running electric vehicle and a regenerative electric vehicle exist in the same power feeding section, and the respective electric powers are balanced. Even under such a condition, a power failure can be detected, and the safety of the railway system is greatly improved. Also,
The control method of the present invention can be realized with a slight modification to the conventional control circuit.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a control device for an AC electric vehicle according to the present invention.

FIG. 2 is a vector diagram of voltage and current of an AC circuit during power running.

FIG. 3 is a vector diagram of voltage and current of an AC circuit during regeneration.

FIG. 4 is a vector diagram of the voltage and current of the AC circuit in a balanced state when a power failure occurs during regenerative operation by conventional control.

FIG. 5 is a vector diagram of voltage and current of an AC circuit when a power failure occurs during regenerative operation when the control method of the present invention is applied.

FIG. 6 is a vector diagram and a control block diagram showing a relationship between a secondary current pattern Isp and a secondary current Is.

FIG. 7: Power running electric vehicle A and regenerative electric vehicle B in the same power feeding section
Explanatory drawing showing the case where there is.

FIG. 8 is an instantaneous waveform diagram of voltage / current of each part at the time of power failure when the control method of the present invention is applied.

FIG. 9 is a circuit diagram showing the polarities between the equivalent circuit of the electric vehicle A and the regenerative electric vehicle B, assuming that the main circuit system of the electric vehicle A performing power running is a resistance control vehicle or a phase control vehicle. .

FIG. 10 is a circuit diagram of a conventional control device for an AC electric vehicle.

[Explanation of symbols]

1 ... overhead line, 2 ... pantograph, 3 ... transformer, 4 ... reactor, 5 ... pulse width modulation converter, 6 ... smoothing capacitor, 7 ... pulse width modulation inverter, 8 ... AC motor, 9
... current detection device, 10 ... vacuum circuit breaker, 11 ... AC power supply,
20, 23 ... Adder, 21 ... AVR, 22 ... Multiplier, 2
4 ... ACR, 25, 34, 41 ... Comparators, 26 and 27
... Pulse width modulation circuit, 30 ... Synchronous power supply filter, 31 ...
Zero cross detector, 32 ... Clock pulse generator, 33
... counter, 35 ... sine wave ROM, 36 ... D / A converter, 37 ... phase setting device, 40 ... cycle detector.

Claims (4)

[Claims] 1. An AC power supply, a transformer having a plurality of windings connected to the AC power supply, a pulse width modulation converter connected to one winding of the transformer, and the pulse width modulation converter. A smoothing capacitor connected to the DC side of
In a motor controller including a pulse width modulation inverter connected to the smoothing capacitor and an AC motor connected to the pulse width modulation inverter, a means for changing the phase of a secondary current pattern, and a power failure of the AC power supply. AC electrical equipment comprising a means for detecting a power failure detection output signal and a control means for outputting a control signal for stopping the pulse width modulation converter and the pulse width modulation inverter by the power failure detection signal. Car controller. 2. The control device for an AC electric vehicle according to claim 1, wherein the means for changing the phase of the secondary current pattern comprises means for adding an offset to an address signal supplied from the counter to the ROM. 3. The power failure detecting means comprises a cycle detecting device for detecting a cycle of the AC voltage, and a comparator for judging whether or not the output of the cycle detecting device is within a set cycle. Item 2. A control device for an AC electric vehicle according to Item 1. 4. The control means for outputting a control signal for stopping the pulse width modulation converter and the pulse width modulation inverter according to the power failure detection signal is the power failure detection signal output from the power failure detection means according to claim 3. The control device for an AC electric vehicle according to claim 1, further comprising control means for receiving and stopping the gate signals of the pulse width modulation converter and the pulse width modulation inverter.