JPH09154203A - Controller for ac electric rolling stock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease higher harmonic components generated in a power supply system of equipment of canceling the higher harmonic components in the power supply system by a first pulse width modulation converter with a second pulse width modulation converter without increasing the size of the equipment. SOLUTION: When two units of first PWM converters 4a and 4b are multiple- operated, higher harmonic components of 9P×50Hz×2=900Hz are generated. The second PWM converter 8 generates at the primary side of the main transformer, a high frequency with a reverse phase and the same frequency component as that of the higher harmonic components required to be canceled, which was generated by the first PWM converters 4a and 4b, and cancels the higher harmonic components. Therefore, by feedback-controlling the output of a current detector 9 at the primary side, the second PWM converter 9 performs the control of canceling the higher harmonic components thereby permitting a considerable reduction in the input current higher harmonics.

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 function of canceling a harmonic component generated in a power system by a pulse width modulation converter for converting an overhead line voltage into a DC voltage in an AC electric vehicle. Is.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional AC electric vehicle disclosed in, for example, "Vehicle Technology No. 191 (June 1990), p.12-13," Outline of JR Tokai 30D Series Shinkansen ". It is a block diagram of the control device of. In the figure, 1 is an AC overhead wire, 2 is a pantograph installed on the roof of a train and in contact with the AC overhead wire 1 to draw power from the AC overhead wire 1 into the vehicle, 3 is installed in the vehicle, and the pantograph 2 and the primary winding 3P Are connected to the secondary windings 3S of the main transformer 3 to reduce the AC voltage (for example, AC20KV) applied to the primary winding 3P. Is connected to the output of the PWM converter 4 for converting a DC voltage into an AC of a variable voltage variable frequency for driving a vehicle. It is a variable voltage variable frequency inverter (hereinafter referred to as a VVVF inverter) that is supplied to the induction motor 6.

Next, the operation of the conventional device will be described.
The conventional control device for an AC electric vehicle is configured as described above, and when an AC voltage is applied from the AC overhead wire 1 to the primary winding 3P of the main transformer 3 via the pantograph 2, this AC voltage is stepped down. It is then input from the secondary winding 3S to each PWM converter 4a, 4b. Each PWM converter 4a, 4
The pulse width modulation control b controls the AC voltage to a constant DC output voltage while maintaining the power factor at approximately 1.

The DC output voltage output from each of the PWM converters 4a and 4b is input to the VVVF inverter 5, where it is converted into an AC voltage having a variable voltage and a variable frequency and output to the induction motor 6.

The main circuit switching elements used in the PWM converters 4a and 4b must use high-power semiconductors, and GTO thyristors are generally used. Although this GTO thyristor is a high withstand voltage, large current element, it is usually used at an operating frequency of 500 Hz or less because the switching time is relatively long and the loss generated during switching is large.

Therefore, when the power supply frequency is 50 Hz, the PWM converters 4a and 4b perform 9-pulse modulation control, so that the input current of the main transformer 3 is 9P × 50H.
A harmonic component of z × 2 = 900 Hz will be generated. This input current harmonic component may adversely affect the ground power equipment and other signal equipment.

Therefore, it is desirable to reduce harmonic components as much as possible, and conventionally, as a harmonic suppression measure, P
A plurality of WM converters 4a and 4b are provided, each of which is PWM
In order to perform a multiple operation by providing a phase difference in the modulation control of the converters 4a and 4b or to suppress a specific harmonic component,
A special modulation control phase difference was set.

As an example, each PWM converter 4
a and 4b are 90 when viewed from the VVVF inverter 5 side.
Double operation with a phase difference of °. When viewed from the primary side of the main transformer 3, each PWM converter 4a,
4b has a phase difference of 0 °, 90 °, 22.5 °, and 112.5 ° and performs switching to suppress a harmonic current near 4 KHz to the AC overhead wire 1 side.

[0009]

Since the conventional AC electric vehicle controller is configured as described above, in order to reduce the input current harmonics, a plurality of PWM converters are used to perform multiple operations. Therefore, the modulation control phase difference of the PWM converter needs to be sufficiently examined in advance by simulation or the like in order to suppress a specific harmonic component. Also, when applying a high-speed switching element to the main circuit element, the high-speed switching element is an element with a relatively low breakdown voltage and a small current capacity, so the number of parallel connection and series connection of the used elements increases, and the size of the device increases. However, there is a problem that the control is complicated.

The present invention has been made to solve the above problems, and an AC electric vehicle capable of reducing the harmonic components generated in the power supply system of the device without increasing the size of the device. The purpose is to obtain a control device of.

[0011]

According to a first aspect of the present invention, there is provided a control device for an AC electric vehicle having a first pulse width connected to each secondary winding of a transformer to which an overhead wire voltage is applied via a pantograph. A modulation converter, an inverter for converting the outputs of these first pulse width modulation converters to AC and supplying the same to an electric motor, a modulation frequency higher than the modulation frequency of the first pulse width modulation converters, and the tertiary of the transformer. A second pulse width modulation converter connected to the winding, wherein the second pulse width modulation converter cancels harmonic components generated in the power supply system by the first pulse width modulation converter. Is.

According to a second aspect of the present invention, in the control device for an AC electric vehicle, the second pulse width modulation converter in the first aspect is the primary side input from the current detector installed in the primary winding of the transformer. The pulse width modulation frequency is set based on the harmonic component in the current.

According to a third aspect of the present invention, there is provided a control device for an AC electric vehicle, wherein in the first aspect, the second pulse width modulation converter is input from a current detector installed in the secondary winding of the transformer. The pulse width modulation frequency is set based on the harmonic component in the secondary current.

According to a fourth aspect of the present invention, in a control device for an AC electric vehicle according to the first aspect, a low speed switching element is used for each first pulse width modulation converter and a high speed switching element is used for the second pulse width modulation converter. It was what I had.

According to a fifth aspect of the present invention, there is provided a control device for an AC electric vehicle according to any one of the first to fourth aspects, wherein the second pulse width modulation converter is the primary side input current harmonic generated by the first pulse width modulation converter. It outputs a harmonic current having a phase opposite to that of the wave component and having a higher frequency to the primary winding.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a block diagram of a control device for an AC electric vehicle according to a first embodiment of the present invention. In the drawing, the same reference numerals as those in FIG. 4 indicate the same or corresponding parts. In the figure, 7 is a tertiary winding provided in the main transformer 3, and a secondary PWM converter 8 is connected to the tertiary winding 7. 9
Is a primary side current detector for detecting the primary side current of the main transformer 3, and the detected current by this primary side current detector 9 is the second
Is input to the PWM converter 8.

Next, the operation of the first embodiment shown in FIG. 1 will be described. First PWM converter 4a, 4b
Is a high-power low-speed switching element such as a GTO thyristor. Therefore, as described above, the 9-pulse modulation control is performed to perform the first PWM converters 4a and 4b.
9P x 50Hz x 2 = 90 when 2 units are operated in multiple
A harmonic component of 0 Hz will be generated.

As a result, the primary side of the main transformer 3 has 900
A harmonic component of Hz appears. In order to control so as to cancel this 900 Hz harmonic component, it is necessary to control by a high frequency of at least 5 to 10 times the generated harmonic frequency.

Therefore, the second PWM converter 8 has 5
It is necessary to perform high frequency modulation operation using a switching element capable of high speed switching operation of about KHz to 10 KHz.

Therefore, the second PWM converter 8 inputs the primary side current of the main transformer 3 from the primary side current detector 9, and passes through a bandpass filter (not shown) to cancel harmonic components (signals and communication equipment in the vicinity). The frequency band that may give an obstacle to the signal is detected, for example, 1 KHz.

Next, the second PWM converter 8 inputs the component of the opposite phase of the detected component (the one in which the plus and the minus are reversed) to a control circuit (not shown) to input the input current of the second PWM converter 8. Control pattern. As a result,
The second PWM converter 8 generates, on the primary side of the main transformer 3, a high frequency component having the same frequency component as the harmonic component to be canceled by the first PWM converters 4a and 4b but having an opposite phase, and the harmonic component is generated. Cancel.

Therefore, the feedback control of the output of the primary side current detector 9 allows the second PWM converter 8 to perform control for canceling the harmonic components, and to significantly reduce the input current harmonics. Become.

That is, the second PWM converter 8 does not supply the large electric power for driving the AC electric vehicle to the VVVF inverter 5, but the first PWM converters 4a, 4a.
Since it suffices to perform control so as to cancel only the higher harmonic component generated by the operation of b, it is possible to use a relatively small power type semiconductor element capable of high-speed switching operation.

Embodiment 2 FIG. In the above-mentioned Embodiment 1,
Although the primary side current detector 9 is provided on the primary side of the main transformer 3 to feed back the detected primary current value to the second PWM converter 8, it is connected to the AC input side of each of the first PWM converters 4 and 4a. A current detector may be provided on the secondary side of the main transformer 3 and the detected secondary current may be input to the second PWM converter 8.

FIG. 2 is a block diagram of a control device for an AC electric vehicle according to this embodiment. In the drawing, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts. In the figure, 10 is a secondary side current detector installed in the secondary winding 3S of the main transformer 3, and this secondary side current detector 10 converts the detected secondary side current into the second PWM converter 8 To enter.

Next, the operation of this embodiment will be described. The second PWM converter 8 includes the secondary side current detector 1
The secondary side current of the main transformer 3 is input from 0, and a harmonic component (a frequency band that may damage a nearby traffic signal or communication equipment, for example, 1 KHz) is detected through a bandpass filter (not shown).

Next, the second PWM converter 8 inputs the component of the opposite phase of the detected component (the one in which the plus and the minus are reversed) to a control circuit (not shown) to input the input current of the second PWM converter 8. Control pattern. As a result,
The second PWM converter 8 causes the main transformer 2 to generate a high frequency wave having an opposite phase and having the same frequency component as the harmonic component to be canceled generated by the first PWM converters 4a and 4b, and cancels the harmonic component.

As a result, the second PWM converter 8
The output of the secondary side current detector 9 detects the harmonic from the source. Therefore, the second PWM converter 8 can cancel the harmonic components effectively by canceling the harmonic components by feedforward control.

Embodiment 3 In the above-described first and second embodiments, in addition to the first PWM converters 4a and 4b for double operation, the second PWM converter 8 for canceling higher harmonic components is used.
Is connected to the tertiary winding 7, but one of a plurality of existing PWM converters for multiple operation may be replaced with a PWM converter having a high-speed switching element and used for canceling harmonic components.

3 (a) and 3 (b) are block diagrams of a control device for an AC electric vehicle according to this embodiment. In FIG. 1, FIG.
The same reference numerals indicate the same or corresponding parts. (A) of FIG.
In the above, reference numeral 8a is a PWM converter that also serves as an active filter for canceling higher harmonic components. As an operation, the multiple operation is performed together with the other PWM converters 4a and 4b to supply the DC power to the VVVF inverter 5, and the switching operation is performed at a frequency higher than the harmonic component generated by the PWM converters 4a and 4b.

As a result, the PWM converter 8a generates a high frequency component in the main transformer 3 having the same frequency component as the harmonic component to be canceled and having an opposite phase, so that the first PWM converter 4a
The harmonic components generated by are canceled out. The PWM converter 8a inputs the primary side current of the main transformer 3 from the primary side current detector 9 as in the first embodiment, and detects the harmonic component to be canceled.

Alternatively, as shown in (b) of the figure, the secondary side current detector 10 provided on the secondary side of the main transformer 3 supplies the secondary side current of the main transformer 3 to the PWM converter 8a. You may make it input and detect the harmonic component which wants to cancel.

It should be noted that if an existing PWM converter connected to the secondary winding 3S of the main transformer 2 is also capable of high-speed switching operation, an active component for canceling higher harmonic components is irrespective of the type of connected DC load. It can be used as a filter. As a result, harmful harmonic components can be suppressed without changing the electric power system of the vehicle.

[Brief description of the drawings]

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

FIG. 2 is a configuration diagram of a control device for an AC electric vehicle according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a control device for an AC electric vehicle according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional control device for an AC electric vehicle.

[Explanation of symbols]

1 AC overhead line, 2 pantograph, 3 main transformer, 3P
Primary winding, 3S Secondary winding, 4a, 4b First P
WM converter, 5 VVVF inverter, 6 induction motor, 7 tertiary winding, 8 and 8a 2nd PWM converter, 9 primary side current detector, 10 secondary side current detector.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H02P 7/63 302 H02P 7/63 302R

Claims (5)

[Claims] 1. A first pulse width modulation converter connected to each secondary winding of a transformer to which an overhead wire voltage is applied via a pantograph, and an AC conversion of the outputs of these first pulse width modulation converters. An inverter for supplying the electric motor; and a second pulse width modulation converter having a modulation frequency higher than that of the first pulse width modulation converter and connected to the tertiary winding of the transformer. A control device for an AC electric vehicle, wherein the second pulse width modulation converter cancels harmonic components generated in the power supply system by the pulse width modulation converter. 2. The second pulse width modulation converter sets the pulse width modulation frequency based on the harmonic component in the primary side current input from the current detector installed in the primary winding of the transformer. The control device for an AC electric vehicle according to claim 1. 3. The second pulse width modulation converter sets the pulse width modulation frequency based on the harmonic component in the secondary side current input from the current detector installed in the secondary winding of the transformer. The control device for an AC electric vehicle according to claim 1, wherein: 4. The control of the AC electric vehicle according to claim 1, wherein a low speed switching element is used for each of the first pulse width modulation converters and a high speed switching element is used for the second pulse width modulation converters. apparatus. 5. The second pulse width modulation converter outputs a higher harmonic current having a phase opposite to that of the primary side input current harmonic component generated by the first pulse width modulation converter to the primary winding. The control device for an AC electric vehicle according to any one of claims 1 to 4, wherein