JP3050234B2 - Electric motor main circuit - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial application field) The present invention relates to an electric motor main circuit for electric railway feeding from a single-phase AC overhead line.

(Prior Art) Conventionally, a configuration as shown in FIG. 3 is known as an electric motor main circuit for an electric railway to be fed from a single-phase AC overhead line.
In this conventional electric motor main circuit for a railway, a primary side of a main transformer 2 and wheels 3 are connected to a pantograph 1. A PWM converter 4 is connected to the secondary side of the main transformer 2 so as to convert a single-phase alternating current to a direct current. A VVVF inverter 6 is coupled to the output of the PWM converter 4 via a capacitor 5.
Is connected to an induction motor 7,
VVVF operation is enabled.

Further, the main transformer 2 is provided with a tertiary winding, and an ot filter 8 is coupled to the tertiary winding so that only a fundamental wave component is extracted from the tertiary winding voltage. A zero-crossing detection circuit 9 is connected to the Ot filter 8 and outputs a synchronizing signal at each zero-crossing point of the fundamental wave. The synchronizing signal is input to a gate control circuit 10 of the converter 4 to determine the phase of the phase at which the converter 4 should operate. Synchronization is matched to the power supply.

In the conventional electric motor main circuit, even when the main circuit is incorporated in each of a plurality of vehicles, the main circuit of each vehicle individually fetches the synchronization signal from the power supply by the zero-cross detection circuit 9, and The converter 4 is controlled independently.

(Problems to be Solved by the Invention) However, such a conventional electric motor main circuit for a railway has the following problems.

That is, although the PWM converter 4 performs synchronous PWM modulation, the phase of the carrier wave at the time of performing the PWM modulation is made different for a plurality of units with respect to the phase of the power supply frequency.
The purpose of this is to eliminate harmonics generated when performing PWM modulation by shifting the phase.

However, in the conventional circuit, since there is no transmission means between different vehicles, when the synchronization signal generated by the zero-cross detection for each vehicle is shifted, the signal is shifted from the phase which should be originally output, and initially, There has been a problem that the phase difference operation for reducing harmonics that has been considered collapses, and harmonics in a frequency band used in a signal system are generated.

The present invention has been made in view of such a conventional problem. One vehicle in the same formation is a parent unit, the other units are child units, and all units in the same formation are one synchronization signal. It is an object of the present invention to provide an electric motor main circuit for an electric railway that operates to fix a phase shift of a carrier wave of each vehicle with respect to a power supply frequency and prevent occurrence of a harmonic that may have an influence when it occurs. I do.

[Means for Solving the Problems] The present invention relates to a transformer having a primary side connected to an AC overhead line,
A PWM converter that is connected to the secondary side of this transformer and converts AC power to DC power, a VVVF inverter that converts the output of this PWM converter to AC with variable voltage and variable frequency, and is driven by the AC output of this VVVF inverter One of the motor main circuits has a zero-cross detecting means for detecting a zero-cross point of an AC power supply from the transformer. Then, the output of the zero-cross detecting means detected by the one motor main circuit is provided as synchronization information to another motor main circuit, and the other motor main circuit is configured based on the synchronization information provided from the one motor main circuit. The PWM
This is to control the converter.

The present invention also provides a transformer having a primary side connected to an AC overhead wire, a PWM converter connected to a secondary side of the transformer and converting AC power to DC power, and a variable voltage variable output from the PWM converter. In a motor main circuit for an electric railway provided with a plurality of motor main circuits each including a VVVF inverter that converts frequency to alternating current and a motor driven by the AC output of the VVVF inverter, each of the motor main circuits is a transformer. A zero-cross point detecting means for detecting a zero-cross point of an alternating current from a motor, and providing an output of the zero-cross detecting means detected by one of the plurality of motor main circuits to another motor main circuit as synchronization information. The other motor main circuit monitors the synchronization information provided from the one motor main circuit, and if the synchronization information is normal, the PW based on the synchronization information. The M converter is controlled, and when the synchronization information is abnormal, the synchronization information is ignored, and the PWM converter is controlled by the output of the zero cross detection means of the motor main circuit.

(Operation) In the electric motor main circuit of the present invention, the zero-cross point of the AC power supply is detected by the zero-cross detecting means of one electric motor main circuit, and this is provided as synchronous information to the other electric motor main circuit. The circuit controls the PWM converter based on the synchronization information provided from the one motor main circuit.

In this manner, the motor main circuit of each vehicle can perform gate control of each converter based on common synchronization information generated by one motor main circuit, and can prevent generation of harmonics.

Further, in the electric motor main circuit of the present invention, the zero cross point of the AC power supply is detected from the transformer of the own circuit by the zero cross detecting means of each electric motor main circuit, and one of the electric motor main circuits of the plurality of electric motor main circuits is detected. The output of the zero-cross detecting means detected by the circuit is provided to another motor main circuit as synchronization information, and the other motor main circuit monitors the synchronization information provided from one motor main circuit, and when the synchronization information is normal. The PWM converter is controlled based on this synchronization information, and when the synchronization information is abnormal, the synchronization information is ignored, and the output of the zero-cross detecting means of the own circuit is used.
Control the PWM converter.

In this way, the motor main circuit of each vehicle can perform gate control of each converter based on the common synchronization information generated by one motor main circuit, and can prevent generation of harmonics. If the synchronization information is abnormal, each motor main circuit can independently perform the gate control of each converter using the output of the zero-cross detection means of its own circuit.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, which includes a parent unit 11 provided in one vehicle and child units 12, 12,... Provided in some other vehicles in the same formation. It is configured. The zero-cross detection circuit 9 is provided in the parent unit 11.
, A gate control circuit 10, and a driver 13. A zero-cross detection circuit 9, a gate control circuit 10, a receiver 14, and a watchdog timer
15 and a changeover switch 16 are provided. Further, a synchronization lead-in line 17 for transmitting a synchronization signal is provided between the driver 13 of the parent unit 11 and the receiver 14 of the child unit 12.

Here, the zero-cross detection circuit 9 and the gate control circuit 10 are inserted in the same reference numerals in the main circuit shown in FIG. Has a configuration in which a driver 13 is further added to the conventional main circuit.
14 and a watchdog timer 15, and a changeover switch 16 is inserted between the zero-cross detection circuit 9 and the gate control circuit 10.

The watchdog timer 15 has the configuration shown in FIG.
A synchronizing signal from the receiver 14 is input to the A terminal of the retriggerable multivibrator 18, and a switching signal for the changeover switch 16 is output from the Q terminal.

Next, the operation of the electric motor main circuit having the above configuration will be described.

In the main unit 11, the output of the tertiary winding of the main transformer 2 is passed through the OT filter 8 to pass only the fundamental wave component in the main circuit shown in FIG. A zero-cross point is detected from the wave component and output as a synchronization signal. The synchronization signal is input to the gate control circuit 10 and controls the gate of the PWM converter 4 of the main circuit of the vehicle including the parent unit 11.

At the same time, the synchronization signal from the zero-cross detection circuit 9 is also supplied to the driver 13, and is transmitted from the driver 13 to the slave unit 12 via the line 17 through synchronization.

On the slave unit 12 side, the synchronization signal is received by the receiver 14 and is supplied to the gate control circuit 10 via the changeover switch 16, and the gate control circuit 10 uses the synchronization signal to control the PWM converter 4 of the main circuit of the own vehicle. Perform control.

The synchronization signal received by the receiver 14 is also supplied to the watchdog timer 15 at the same time as described above, and the watchdog timer 15 continuously monitors whether the pulse signal of the synchronization signal is correctly input.

The synchronizing signal monitoring operation of the watchdog timer 15 will be further described. The synchronizing signal is applied to the A terminal of the retriggerable multivibrator 18 for 16.6 ms as shown in FIG.
If it is input within this time, the Q terminal of the multivibrator 18 remains at L. Therefore, the changeover switch 16 connects the receiver 14 to the gate control circuit 10 and controls the PWM converter 4 of the main circuit of the own vehicle while synchronizing with the master unit 11 side.

If the synchronization signal received by the receiver 14 is not input within 16.6 ms, the Q terminal of the watchdog timer 15 is set to H, and the changeover switch 16 switches the connection to the zero-cross detection circuit 9 provided on the slave unit 12 side. Then, a zero-cross point is detected for the fundamental wave component of the power supply frequency taken from the tertiary winding of the main circuit of the own circuit, and this is supplied to the gate control circuit 10 as a synchronization signal to perform the gate control of the PWM converter 4. Let

In this way, the PWM converters 4 of all the vehicles are normally controlled in synchronization with the synchronization signal given from the parent unit 11, and the synchronization signal of the main circuit of each vehicle is shifted in phase to generate harmonics, The system can be prevented from adversely affecting the system, while the watchdog timer 15 constantly monitors the synchronization signal from the parent unit 11,
If the synchronization signal from the parent unit 11 becomes incorrect, the gate control of the PWM converter 4 can be continued using the zero-cross point signal from the zero-cross detection circuit 9 provided in the main circuit of the vehicle as the synchronization signal. It is.

It should be noted that the present invention is not limited to the above embodiment, and the synchronization signal is always supplied from the parent unit 11 to each child unit 12 without monitoring the synchronization signal by the watchdog timer. The main circuits of all the vehicles may be simultaneously driven only by the signal.

[Effects of the Invention] As described above, according to the present invention, the other motor main circuits also control the converter based on the synchronization information obtained by the zero-cross detecting means of one motor main circuit. Based on the synchronization information, the phase shift of the gate control signal of the PWM converter for each vehicle can always be set to a fixed and fixed relationship, and it is possible to reliably prevent the generation of harmonics as in the past. .

Further, according to the present invention, the zero-cross point of the AC power source is detected from the transformer of the own circuit by the zero-cross detecting means of each motor main circuit, and detected by one of the plurality of motor main circuits. The output of the zero-cross detecting means is provided as synchronization information to another motor main circuit, and the other motor main circuit monitors the synchronization information provided from one motor main circuit. The PWM converter is controlled based on the information, and when the synchronization information is abnormal, the synchronization information is ignored and the PWM converter is controlled by the output of the zero-cross detecting means of the own circuit. Motor main circuit is 1
The gate control of each converter can be performed by the common synchronization information generated by the two motor main circuits, and it is possible to reliably prevent the generation of harmonics as in the conventional case. Then, each motor main circuit can independently perform the gate control of each converter using the output of the zero-cross detecting means of its own circuit.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of one embodiment of the present invention, FIG. 2 is a block diagram showing a circuit configuration of a watchdog timer in the above embodiment, and FIG. 3 is a circuit block diagram of a conventional example. 1 Pantograph, 2 Main transformer 4 PWM converter 6 VVVF inverter 7 Electric motor 8, Ot filter 9 Zero cross detection circuit 10 Gate control circuit 11, Parent unit 12 ... Slave unit, 13 ... Driver 14 ... Receiver 15 ... Watch dock timer 16 ... Switch

Claims (2)

(57) [Claims] A transformer having a primary side connected to an AC overhead wire;
A PWM converter that is connected to the secondary side of this transformer and converts AC power to DC power, a VVVF inverter that converts the output of this PWM converter to AC with variable voltage and variable frequency, and is driven by the AC output of this VVVF inverter A main motor circuit for a railway provided with a plurality of electric motor main circuits each including a motor to be driven, wherein one of the electric motor main circuits has a zero cross detection means for detecting a zero cross point of an AC power supply from the transformer. The output of the zero-cross detecting means detected by the one motor main circuit is provided as synchronization information to another motor main circuit, and the other motor main circuit uses the synchronization information provided from the one motor main circuit as the synchronization information. And an electric motor main circuit for controlling the PWM converter. 2. A transformer having a primary side connected to an AC overhead line,
A PWM converter that is connected to the secondary side of this transformer and converts AC power to DC power, a VVVF inverter that converts the output of this PWM converter to AC with variable voltage and variable frequency, and is driven by the AC output of this VVVF inverter A motor main circuit for an electric railway provided with a plurality of motor main circuits each including: a motor to be driven, wherein each of the motor main circuits has a zero-cross detection means for detecting a zero-cross point of an AC power supply from the transformer. The output of the zero-cross detection means detected by one of the plurality of motor main circuits is provided as synchronization information to another motor main circuit, and the other motor main circuit is provided by the one motor main circuit. Monitor the synchronization information
If the synchronization information is normal, the synchronization information
Controlling a PWM converter, ignoring the synchronization information if the synchronization information is abnormal, and controlling the PWM converter based on the output of the zero-crossing detection means of the motor main circuit of the electric train; Main circuit.