JPH0241605A - Controller for ac electric rolling stock - Google Patents

Abstract

PURPOSE:To detect a power interruption of a trolley wire early by outputting a stop command signal if the variation value of an AC current on the primary side of a transformer is negative and its absolute value is larger than a reference value. CONSTITUTION:After an AC current at the primary side of a transformer 22 detected by a current transformer 6 is rectified by a rectifier 7, it is smoothed by a smoothing circuit 8. After the output of the smoothing circuit 8 is differentiated by a differentiator 9, it is compared by a comparator 11 with a reference value of a current change reference setter 10. If the variation of the current is negative and its absolute value is larger than a reference value, a power interruption detection signal is output from the comparator 11. A stop command signal is output from an AND circuit 12 on the basis of the detection signal and an operation command. If the AC voltage at the primary side of the transformer 22 is lower than the reference value, the detection signal is output from a comparator 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a control device for an AC electric vehicle that includes a converter and an inverter and has an AC power regeneration function.

(Conventional technology) FIG. 3 shows a conventional control device for an AC electric vehicle.

This control device includes a current collector 21, a transformer 22, and a reactor 2.
3. Used in an AC electric vehicle having a pulse width modulation converter (hereinafter also referred to as a PWM converter) 24, a capacitor 25, an inverter 26, and an AC motor 27, including a transformer 1, a rectifier circuit 2, and a smoothing circuit 3. , a voltage reference setting device 4 , a comparator 5 , a converter control circuit 14 , and an inverter control circuit 15 . The PWM converter 24 is a gate turn-off thyristor (hereinafter referred to as a GTO).
It consists of self-extinguishing switching elements such as
The AC power supplied through the transformer 22 and the reactor 23 is converted into DC power, and the DC power is transmitted to the inverter 26 through the capacitor 25. During regenerative braking operation, DC power is converted to AC power, and reactor 2
3. Regenerate AC power to the overhead wire via the transformer 22 and current collector 21. The inverter 26 converts the DC power transmitted through the capacitor 25 into a variable voltage during the continuous operation.
Variable frequency control is performed to convert the power into AC power, which drives the AC motor 27. During regenerative braking operation, AC power obtained by the AC motor 27 is converted into DC power. The capacitor 25 suppresses pulsations in the DC voltage due to the fact that the overhead line is a single-phase AC power supply and the effects of switching in the PWM converter 24 and inverter 26 . The converter control circuit 14 also includes a main controller (not shown).
The phase of the PWM converter 24 is controlled based on the operation command issued from the PWM converter 24 so that the voltage of the capacitor 25 is always kept constant even if the operating state of the inverter 26 changes. Note that this control is performed by using a phase signal of the overhead wire voltage detected by the transformer 1, which will be described later, as a synchronization signal.

The inverter control circuit 15 controls the phase of the inverter 26 so that the rotational speed and torque of the AC motor 27 become values corresponding to the driving command issued from the main controller.

The transformer 1 detects the alternating current voltage on the primary side of the transformer 22.

This detected AC voltage is rectified in a rectifier 2,
Smoothing is performed in the smoothing circuit 3. The smoothed value is compared with the reference value output from the voltage reference setting device 4 in the comparator 5.

When the smoothed value is lower than the reference value, that is, when the overhead wire is out of power, a power outage detection signal is output from the comparator 5. Then, based on this power failure detection signal, converter control circuit 14 and inverter control circuit 15 stop the operations of PWM converter 24 and inverter 26, respectively.

(Problem to be Solved by the Invention) If a power outage occurs in the overhead wire during the vehicle operation, energy cannot be supplied from the overhead wire, the voltage of the capacitor 25 decreases, and as a result, the AC side voltage of the PWM converter 24 also decreases. As a result, a power outage can be detected by the conventional control device shown in FIG. However, since it takes time for the voltage to change, conventional control devices are delayed in detecting a power outage. In particular, the lighter the load, the longer the delay tends to be.

Further, in the event of a power outage during regenerative braking operation, the voltage of the PWM converter 24 increases, which cannot be detected by conventional control devices. A method of detecting the voltage increase of the PWM converter 24 may also be considered, but the problem of detection delay remains. In either case, the PWM converter 24 will continue to operate even after the substation stops transmitting power. Therefore, after power outage PWM
If power is retransmitted while the converter 24 is operating, and the phase of the power supply voltage and the phase of the AC side voltage of the PWM converter 24 are largely out of phase, an excessive amount of current will flow through each part. In addition, if the overhead wire stopped during regenerative braking and continued regenerative braking, the voltage of the capacitor 25 would become excessive because power would not be regenerated to the overhead wire, and in either case, there was a risk of equipment damage. .

The present invention has been made in consideration of the above problems, and includes:
In both driving mode and regenerative braking mode,
An object of the present invention is to provide a control device for an AC electric vehicle that can prevent damage to equipment as much as possible.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a converter that converts AC power supplied from an AC power source via a current collector and a transformer into DC power;
A DC circuit consisting of a capacitor connected to the output side of this converter, an inverter that converts the DC power inputted through this DC circuit and converted by the converter into AC power, and the AC power converted by this inverter. A converter control circuit is used in an AC electric vehicle having an AC motor to be driven, and controls the phase of the converter so that the voltage of the DC circuit becomes a predetermined value based on a driving command, and the rotation speed of the AC motor. and an inverter control circuit that controls the phase of the inverter so that the torque becomes a value according to the driving command. , an average value processing circuit that outputs an average value of the alternating current detected by this current detector, a differentiation circuit that differentiates the output of this average value processing circuit, and an output of this differentiation circuit that is a negative value, and a comparison circuit that outputs a stop command signal when the absolute value of the output of the differentiating circuit is larger than a preset reference value, and the converter control circuit and inverter control circuit operate the converter and inverter based on the stop command signal. It is characterized by stopping each of the.

(Function) In general, in the normal control of AC electric cars, the current is controlled to change gradually, so a sudden decrease in current that exceeds a certain limit can be considered a power outage. On the other hand, according to the control device for an AC electric vehicle according to the present invention configured as described above, the AC current on the primary side of the transformer is detected by the current detector, and the average value of the AC current is output by the average value processing circuit. be done. Then, by differentiating the output of the average value processing circuit in a differentiating circuit, a change value of the current is detected. This current change value is compared with a preset reference value in a comparison circuit, and if the current change value is a negative value and its absolute value is greater than the reference value, a stop command signal is sent to the comparison circuit. is output from. Therefore, if the overhead line is out of power, a stop command signal will be output from the comparator circuit. Based on this stop command signal, the converter control circuit and the inverter control circuit stop the operations of the converter and inverter, respectively.

Since the value of change in current during a power outage generally decreases quickly, according to the control device for an AC electric vehicle according to the present invention,
In both cases of continuous operation and regenerative braking operation, power outages in overhead wires can be detected earlier than in conventional systems, thereby making it possible to prevent damage to equipment as much as possible.

(Embodiment) FIG. 1 shows a first embodiment of a control device for an AC electric vehicle according to the present invention. The control device of this embodiment includes a current collector 21, a transformer 22, a reactor 23, a pulse width modulation converter (
(hereinafter also referred to as PWM converter) 24, capacitor 2
5, used in an AC electric car having an inverter 26 and an AC motor 27, a transformer 1, a rectifier circuit 2,
A smoothing circuit 3, a voltage reference setter 4, a comparator 5, a current transformer 6, a rectifier circuit 7, a smoothing circuit 8, a differentiator circuit 9,
A current change reference setter 10, a comparator 11, an AND circuit 12, an OR circuit 13, a converter control circuit 14,
The inverter control circuit 15 is also provided. Current transformer 6, rectifier circuit 7, smoothing circuit 8, differentiation circuit 9, current change reference setting device 10. Since the components other than the comparator 11, the AND circuit 12, and the OR circuit 13 have already been explained in the prior art section, their explanation will be omitted.

Next, the structure and operation of the first embodiment will be explained using FIG. 1. The alternating current on the primary side of the transformer detected by the current transformer 6 is rectified in a rectifier circuit 7 and smoothed in a smoothing circuit 8 . The output of the smoothing circuit 8 is differentiated by a differentiating circuit 9 and sent to a comparator 11, where it is compared with a reference value output from a current change reference setting device 10.

When the output of the differentiating circuit, that is, the amount of change in current is negative and its absolute value is larger than the reference value, the comparator 11 outputs a power failure detection signal. The AND circuit 12 outputs an operation signal based on this power failure detection signal and an operation command sent from a master controller (not shown). And AN
Based on the output of the D circuit 12 and the output of the comparator 5, the OR circuit 13 outputs a stop command signal.

Based on this stop command signal, converter control circuit 14 and inverter control circuit 15 stop the operations of PWM converter 24 and inverter 26.

Generally, even when the PWM converter 24 is operating during an overhead line power outage, that is, when the substation stops power transmission, the impedance of the overhead line seen from the transformer 22 is very large, so the primary current of the transformer 22 rapidly decreases.

Therefore, according to the control device of the first embodiment shown in FIG. 1, a power outage in the overhead wire can be detected quickly, thereby making it possible to prevent damage to equipment as much as possible. Also, A
By taking the logical product of the output of the comparator 11 (power failure detection signal) and the operation command sent from the main controller in the ND circuit 12, the comparator 11 is The power outage detection signal, which is the output of the power outage detection signal, is masked to prevent malfunction of power outage detection.

FIG. 2 shows a second embodiment of the control device for an AC electric vehicle according to the present invention. The control device of this embodiment includes a current collector 21, a transformer 22, a reactor 23, a PWM converter 24A1
It is used in an AC electric vehicle having a capacitor 25, an inverter 26A1, and an AC motor 27, and a transformer 1,
A rectifier circuit 2A, a smoothing circuit 3A, a voltage reference setter 4, a comparator 5, a current transformer 6, a rectifier circuit 7A, a smoothing circuit 8A, a differentiator circuit 9, and a current change reference setter 10. , a comparator 11, an AND circuit 12, an OR circuit 13, a converter control circuit 14, and an inverter control circuit 15.

PWM converter 24A1 inverter 26A1 rectifier circuit 2A, smoothing circuit 3A, rectifier 7A, and smoothing circuit 8A
The rest is the same as the first embodiment, so the explanation will be omitted.

The PWM converter 24A is composed of a gate turn-off thyristor and a diode, and has the same function as the PWM converter 24 of the first embodiment shown in FIG. The inverter 26A also includes a gate turn-off resistor and a diode, and has the same function as the inverter 26 of the first embodiment shown in FIG. Rectifier 2
A is composed of a diode, and rectifies the primary side power of the transformer 22 detected by the transformer 1. Smoothing circuit 3A
is composed of a resistor 3a and a capacitor 3b, and a rectifier 2
Smooth the output of A. The output of the smoothing circuit 3A is then sent to the comparator 5 as in the first embodiment. Rectifier circuit 7
A is composed of a diode, and rectifies the primary current of the transformer 22 detected by the current transformer 6. Smoothing circuit 8A
are capacitors 8a, 8b, 8c, resistors 8c, 8d,
It is composed of twin T-type filters connected as shown in Fig. 8e and rectifies the output of the rectifier circuit 7A. The characteristics of this twin T-type filter 8A are the respective capacitances of capacitors 8a, 8b, and 8c, and resistors 8c, 8d,
A specific frequency f determined by each resistance value of 8e
It suppresses nearby frequencies.

In this second embodiment, the specific frequency f is set to be twice the frequency of the power supply [
A faster response can be obtained than a π-type low-pass filter. The output of the smoothing circuit 8A is sent to the differentiating circuit 9 similarly to the control device of the first embodiment.

As described above, according to the second embodiment, effects similar to those of the first embodiment can be obtained.

In addition, in the first and second embodiments, the configuration was shown in combination with a conventional method of detecting a power outage based on a detected voltage value, but a method of detecting a power outage by detecting a change in current may be used. Similar effects can be obtained even when used alone.

〔Effect of the invention〕

According to the present invention, an overhead power outage can be detected early in both the power-line operation and the regenerative braking operation, thereby making it possible to prevent damage to equipment as much as possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of the control device for an AC electric vehicle according to the present invention, and FIG. 2 is a block diagram showing a second embodiment of the control device for an AC electric vehicle according to the present invention. 3
The figure is a block diagram showing a conventional control device for an AC electric vehicle. 1... Transformer, 2, 7... Rectifier circuit, 3.8...
Smoothing circuit, 4... Voltage reference setter, 5, 11... Comparator, 6... Current transformer, 9... Differentiating circuit, 10...
Current change reference setter, 12...AND circuit, 13...
・OR circuit, ]4... converter control circuit, 15...
・Inverter control circuit, 21... Current collector, 22...
Transformer, 23...Reactor, 24...PWM converter, 25...Capacitor, 26...Inverter, 27...AC motor. Applicant's agent Mr. Sato

Claims (1)

[Claims] A DC circuit consisting of a converter that converts AC power supplied from an AC power supply via a current collector and a transformer into DC power, a capacitor connected to the output side of the converter, and this DC circuit. Used in an AC electric vehicle having an inverter that converts the DC power inputted through the converter into AC power, and an AC motor driven by the AC power converted by the inverter, a converter control circuit that controls the phase of the converter so that the voltage of the DC circuit becomes a predetermined value based on a driving command; A control device for an AC electric vehicle comprising an inverter control circuit that controls the phase of an inverter, comprising: a current detector that detects an alternating current on the primary side of the transformer; and an alternating current detected by the current detector. an average value processing circuit that outputs an average value; a differentiation circuit that differentiates the output of this average value processing circuit; and an output of this differentiation circuit that is a negative value and an absolute value of the output of the differentiation circuit that is set in advance. the converter control circuit and the inverter control circuit respectively stop the operations of the converter and the inverter based on the stop command signal. AC electric car control device.