JPH0898317A - Controller of ac electric vehicle - Google Patents

Abstract

PURPOSE: To perform the optimum harmonic control by a method wherein a zero-cross signal from one of a plurality of sets of the respective voltage detectors is used as a common zero-cross signal and used as the timing reference of a plurality of respective control logic units. CONSTITUTION: Three main converters 12a-12c are provided in one formation of vehicles. Pantographs 2a-2c, PT's 9a-9c and main transformers 3a-3c are provided to drive respective induction motors 8a-8c. Zero-cross signals Sa-Sc which are once inputted to control logic units 11a-11c from ACPT's 10a-10c are inputted to a synchronous signal selector 13 which selects one common zero-cross signal S1 among the signals Sa-Sc in accordance with a predetermined priority order and supplies the signal S1 to the respective control logic units 11a-11c as a timing reference. With this constitution, the optimum phase-shift conditions which suppress the harmonics can be always realized as a whole vehicle formation accurately and a high harmonic suppression effect can be realized even if the error characteristics of the respective PT's 9a-9c and the ACPT's 10a-10c have variations.

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, and more particularly to a control device for an AC electric vehicle capable of achieving high-accuracy suppression of harmonics.

[0002]

2. Description of the Related Art A block diagram of a conventional control device for an AC electric vehicle is shown in FIG. In the figure, 1 is an AC overhead wire, 2 is a pantograph in contact with the AC overhead wire 1, 3 is a main transformer connected to the pantograph 2, and 3-1 is a pantograph 2
Primary winding 3-2, 3- of the main transformer 3 directly connected to
3 is a secondary winding of the main transformer 3, 4 and 5 have their input sides connected to the secondary windings 3-2 and 3-3, respectively, and their output sides are commonly connected. Converter (hereinafter referred to as PWM converter), 6 is a smoothing capacitor of an intermediate DC circuit connected between two terminals on the common output side of the PWM converters 4 and 5, and 7 is connected to the output side of the PWM converters 4 and 5. And a variable voltage variable frequency inverter (hereinafter referred to as VVVF inverter) having a smoothing capacitor 6 connected between its two input terminals, 8
Is an induction motor, which is a vehicle motor connected to the output side of the VVVF inverter 7.

Reference numeral 9 is a transformer (hereinafter referred to as PT) for reducing the voltage of the AC overhead wire 1, and 10 is connected to PT9,
A voltage detector (hereinafter referred to as ACPT) 11 that detects a zero-cross point of the input AC voltage and outputs a zero-cross signal that is a timing signal thereof, 11 is connected to the ACPT 10,
The phase control signal created by using the zero-cross signal as a timing reference is sent to the PWM converters 4 and 5 to perform PWM.
It is a control logic unit that controls the converters 4 and 5, and its output side is connected to the PWM converters 4 and 5. Reference numeral 12 is a main converter that houses the PWM converters 4, 5, the smoothing capacitor 6, the VVVF inverter 7, the ACPT 10, and the control logic unit 11.

FIG. 4 shows a control block diagram for controlling the operations of the PWM converters 4 and 5 disclosed in Japanese Patent Publication No. 04-35990. In the figure, 20, 21, 2
2, 23 and 24 are amplifiers, 25 is a multiplier, 26 and 27 are triangular wave forming circuits, and 28, 29, 30, 31, and 32 are subtractors.

Next, the operation of the above circuit will be described.
The difference between the target value V _d ^* of the intermediate DC voltage on the output side of the PWM converters 4, 5 and the actual intermediate DC voltage value V _d is taken by the subtractor 28, and the value is amplified by the amplifier 20 and the AC overhead wire. The unit sine wave sinωt having the same frequency as 1 is multiplied by the multiplier 2
In step 5, the secondary current target value I _s ^* on the input side of the PWM converters 4 and 5 is calculated. Differences between the secondary current target value I _s ^* and the actual secondary currents I _s1 and I _s2 of the PWM converters 4 and 5 are respectively subtracted by subtracters 29 and 30 and amplified by amplifiers 21 and 22, respectively. Wave e _i ,
Calculate e _i ′.

By the way, the harmonic current components generated by the ON / OFF operation of the switching elements in the PWM converters 4 and 5 are combined in the main transformer 3 and flow out to the AC overhead line 1 via the pantograph 2. By shifting the control phases of converters 4 and 5 by 90 °, harmonics flowing out to AC overhead line 1 can be suppressed. Therefore, the triangular wave generation circuits 26 and 27 of FIG.
A triangular wave for PWM whose phases are shifted from each other with the zero-cross signal from 10 as a timing reference is generated. Then, the difference between the fundamental waves e _i and e _i ′ of the voltages from the amplifiers 21 and 22 and the triangular waves from the triangular wave generating circuits 26 and 27 is taken by the subtracters 31 and 32, and the values are amplified by the amplifiers 23 and 24. And a phase control signal for operating the PWM converters 4 and 5.

The phase control signals created above are output from the control logic unit 11 to the PWM converters 4 and 5, respectively, and the PWM converters 4 and 5 are operated so as to suppress harmonics, and the smoothing capacitor 6 is charged. The smoothing capacitor 6 is used as a voltage source to operate the VVVF inverter 7 to drive the induction motor 8. When a plurality of sets of the circuit shown in FIG. 3 are provided in the vehicle formation, the PW of each set is provided.
By shifting the control phase between the M converters,
It is possible to suppress harmonics in the entire vehicle formation.

[0008]

Since the conventional control apparatus for an AC electric vehicle is constructed as described above, when a plurality of sets of the circuit shown in FIG. 3 are provided in the formation, the control logic of each set is provided. Since each unit 11 creates a predetermined phase control signal by using the zero-cross signal from the ACPT 10 of the set as a timing reference, for example, variations in the contact state between the pantograph 2 and the AC overhead wire 1 and PT9 and ACPT10.
Due to the variation in the error characteristics of each group, the timing reference itself of each group will be displaced, and as a result, the control phase of the PWM converter of each group will match the optimum phase shifting condition for suppressing the harmonics of the entire train. Therefore, there is a problem that a sufficient harmonic suppression effect cannot be obtained.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a control device for an AC electric vehicle that can always obtain an optimum harmonic suppression effect.

[0010]

According to another aspect of the present invention, there is provided a control device for an AC electric vehicle, wherein each of the plurality of sets of control logic units detects a predetermined voltage of one of the plurality of sets of voltage detectors. The zero-cross signal from the instruments is input as a common zero-cross signal and this is used as a timing reference.

The control device for an AC electric vehicle according to claim 2 inputs the zero-cross signals from a plurality of sets of voltage detectors, and selects from the input zero-cross signals based on a preset priority. The synchronization signal selection circuit for sending the unique zero-cross signal as a common zero-cross signal to each of the plurality of control logic units is provided.

[0012]

In the AC electric vehicle controller according to the first aspect, each control logic unit creates a phase control signal for each converter with a single common zero-cross signal as a timing reference. Is achieved.

Further, in the control device for the AC electric vehicle according to the second aspect, the synchronization signal selection circuit always selects the single common zero-cross signal and sends it to each control logic unit.

[0014]

【Example】

Example 1. 1 is a block diagram showing a configuration of a control device for an AC electric vehicle according to a first embodiment of the present invention.
It is provided with a main conversion device 12a, 12b, 12c. Accordingly, the pantographs 2a, 2b, 2c, P
T9a, 9b, 9c and main transformers 3a, 3b, 3c are provided to drive the induction motors 8a, 8b, 8c, respectively. Reference numeral 13 newly provided in FIG. 1 is a synchronization signal selection circuit, which is once provided with the control logic units 11a, 11b and 11c, respectively.
Input the zero-cross signals Sa, Sb, Sc from the ACPTs 10a, 10b, 10c input to the, and the only common zero-cross signal selected from these zero-cross signals Sa, Sb, Sc based on the preset priority order. S
₁ is sent to the control logic units 11a, 11b and 11c, respectively.

FIG. 2 is a table showing the selection criteria of the zero-cross signal processed by the synchronizing signal selection circuit 13. As for the priority order, the zero-cross signal Sa is the first and the order is Sb and Sc. Therefore, when all the main converters 12a, 12b, 12c are operating normally, the zero-cross signal Sa is selected as the common zero-cross signal S ₁ , and each control logic unit 11a, 11
b, 11c. Further, when the main conversion device 12a is out of order, and therefore the main conversion devices 12b and 12c are operating, the zero-cross signal Sb having the higher priority is selected as the common zero-cross signal S ₁ among these two, and It is sent to the control logic units 11b and 11c.

Since the operation of the control logic unit 11 and the subsequent parts is the same as the conventional one, duplicated description will be avoided, but in the circuit of FIG. 1, all the PWM converters 4 during the operation of the vehicle formation,
The phase shift of the phase control signal supplied to 5 is calculated by using the common zero-cross signal S ₁ as a timing reference. Therefore, the optimum phase shift condition for suppressing the harmonics of the entire knitting is accurately and surely achieved without being affected by variations in the error characteristics of the individual PTs 9 and ACPTs 10, and a high harmonic suppression effect is always obtained. .

When some of the main converters 12 are out of order due to a failure, as described above, the common zero-cross signal S ₁ is selected from the remaining operating devices based on the priority, and each control is performed. Since the logic unit 11 calculates the phase shift of the phase control signal to the operating PWM converters 4 and 5 by using the common zero-cross signal S ₁ as a timing reference, the operating PWM converters 4 and 5 in the composition Suppression of harmonics flowing out from is realized under optimum conditions.

When the number of operating PWM converters 4 and 5 in the formation changes due to a device failure or the like, the phase shift of the phase control signals to the respective converters is naturally corresponding to the number. Change the corner.

Example 2. In the above embodiment, one main converter 12 is provided with two PWM converters 4 and 5, and the direct current output thereof is further converted into a three-phase alternating current by the VVVF inverter 7 to drive the induction motor 8. However, the present invention can be similarly applied to, for example, a system in which each main conversion device 12 is provided with one converter and a direct current motor is directly driven by its direct current output, and the same effects are obtained. Further, it goes without saying that the number of main conversion devices 12 and the like is not limited to three. Furthermore, there is always only one common zero-cross signal S
_The method of supplying ₁ to each control logic unit 11 is not always the same as in FIG.
The method is not limited to the method provided with the synchronization signal selection circuit 13 shown in FIG.

[0020]

As described above, since each control logic unit in the control device for an AC electric vehicle according to claim 1 creates a phase control signal for each converter by using only one common zero-cross signal as a timing reference, The desired exact phase shift condition is achieved and the harmonics are always suppressed under optimum conditions.

Further, since the control device for the AC electric vehicle according to claim 2 is provided with the predetermined synchronizing signal selecting circuit, this synchronizing signal selecting circuit always selects only one common zero-cross signal, and the harmonic wave is generated under the optimum condition. The control operation for obtaining the suppression is smoothly performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control device for an AC electric vehicle according to a first embodiment of the present invention.

FIG. 2 is a table in which selection criteria of zero-cross signals are summarized in the form of a table.

FIG. 3 is a block diagram showing a configuration of a conventional control device for an AC electric vehicle.

FIG. 4 is a block diagram showing a control mechanism of a PWM converter.

[Explanation of symbols]

1 AC overhead line, 2 pantograph, 4, 5 PWM converter, 9 PT, 10 ACPT, 11 control logic section, 13 sync signal selection circuit, Sa, Sb, Sc, S ₁
Zero-cross signal.

Claims (2)

[Claims] 1. A pantograph, a converter for converting AC power input from an AC overhead wire via the pantograph to DC power, a zero-cross point of an AC voltage input via the pantograph, and a zero-cross signal which is a timing signal thereof. An AC electric vehicle having a plurality of sets of a voltage detector for outputting a signal and a control logic unit for sending the phase control signal created by using the zero-cross signal as a timing reference to the converter to control the converter. In the control device, each of the plurality of sets of control logic units inputs a zero-cross signal from a predetermined one voltage detector among the plurality of sets of each voltage detector as a common zero-cross signal, and inputs the zero-cross signal. A control device for an AC electric vehicle, which is characterized by using a timing reference. 2. A pantograph, a converter for converting AC power input from an AC overhead wire via this pantograph into DC power, a zero-cross point of an AC voltage input via the pantograph, and a zero-cross signal which is its timing signal. An AC electric vehicle having a plurality of sets of a voltage detector for outputting a signal and a control logic unit for sending the phase control signal created by using the zero-cross signal as a timing reference to the converter to control the converter. In the control device, the zero-cross signals from the voltage detectors of the plurality of sets are input, and the only zero-cross signal selected from the input zero-cross signals based on the preset priority is used as the common zero-cross signal. A synchronization signal selection circuit for sending to each of the plurality of sets of the control logic units. That AC electric vehicle of the control device.