JPH05308701A - Ac electric vehicle controlling equipment - Google Patents

Abstract

PURPOSE:To provide an ac electric vehicle controlling equipment which is easy to maintain and requires no capacitance meter separately. CONSTITUTION:The amount of charge stored in a smoothing capacitor 6 is determined by integrating the current detected by an ac current detector 12A by an integrator 16. The amount of charge determined is divided by a divider 17 by the voltage of the smoothing capacitor 6 which was detected by a dc voltage detector for controlling 13. The value then obtained is the capacitance of the smoothing capacitor 6.

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 an AC electric vehicle which automatically detects the capacity of a smoothing capacitor used in an inverter of an electric motor for a vehicle. The present invention relates to a control device.

[0002]

2. Description of the Related Art A conventional AC electric vehicle controller will be described with reference to FIG. Figure 3 shows, for example, the Institute of Electrical Engineers, 1990, February 2.
The main circuit configuration of a conventional control device for an AC electric vehicle described in Vol. 110, No. 2 is shown.

In FIG. 3, 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 3a is a primary winding of a main transformer 3 connected to the pantograph 2. Lines 3b and 3c are 2 of main transformer 3
Secondary windings 4 and 5 are PWM-controlled converters (hereinafter referred to as “PWM converters”) connected to the secondary windings 3b and 3c, respectively, and 6 is connected in parallel to the PWM converters 4 and 5 to form an intermediate DC circuit. Is a smoothing capacitor (for example, an electrolytic capacitor), 7 is a variable voltage variable frequency inverter (hereinafter, referred to as “V
"VVF inverter". ), 8 are induction motors connected to the VVVF inverter 7. Further, 9A and 9B are respectively connected between one output terminal of the secondary windings 3b and 3c and one input terminal of the PWM converters 4 and 5, and are short-circuit switches which are opened at the time of starting, 10 is a charging resistor, 11 Is a charging switch that is closed at startup, and a series circuit composed of the charging resistor 10 and the charging resistor 11 is connected in parallel to the short-circuit switch 9A.
12A and 12B are connected between the other output terminals of the secondary windings 3b and 3c and the PWM converters 4 and 5, and are a control AC current detector (hereinafter, referred to as "ACCT") that detects a control AC current. , 13 is a control DC voltage detector (hereinafter, referred to as “DCPT”) for detecting a control DC voltage.
That. ). A circuit breaker 14 is connected between the pantograph 2 and the main transformer 3.

Next, the operation will be described. Main transformer 3
Reduces the AC voltage of the AC overhead wire 1. The PWM converters 4 and 5 convert the input alternating current into direct current, and the smoothing capacitor 6 smoothes this direct current. VVVF inverter 7
Converts the smoothed direct current into alternating current of variable voltage variable frequency and inputs it to the induction motor 8.

When the control device is activated, an excessive current for initial charging of the smoothing capacitor 6 flows, and P
There is a risk of destroying the switching elements that make up the WM converters 4 and 5, so in order to prevent this, the short-circuit switch 11 is closed to start with the charging resistor 10 until the smoothing capacitor 6 is completely charged. The current is limited and the switch 9B is opened to disconnect the PWM converter 5.

[0006]

By the way, the smoothing capacitor used as the smoothing capacitor 6 has a property that its capacity decreases due to deterioration over time. However, since the conventional AC electric vehicle control device as described above does not have any means for detecting the capacity of the smoothing capacitor 6, it is necessary to periodically measure the capacity of the smoothing capacitor 6, and maintenance thereof is required. There was a problem that it took time. There is also a problem that a separate capacitance meter is required for measuring the capacitance.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to obtain a control device for an AC electric vehicle that is easy to maintain and does not require a capacity meter separately.

[0008]

The control device for an AC electric vehicle according to the present invention comprises the following means. [1] A converter that converts alternating current stepped down by a main transformer into direct current. [2] A smoothing capacitor that smoothes and supplies the direct current to an inverter that feeds an electric motor. [3] A capacitance detecting means for detecting the capacitance of the smoothing capacitor based on the current and voltage of the smoothing capacitor.

[0009]

In the control device for an AC electric vehicle according to the present invention, the AC voltage stepped down by the main transformer is converted into the DC voltage by the converter. Further, the smoothing capacitor smoothes and supplies the direct current to the inverter that feeds the electric motor. Then, the capacitance detecting means detects the capacitance of the smoothing capacitor based on the current and voltage of the smoothing capacitor.

[0010]

EXAMPLES Example 1. FIG. 1 shows the configuration of Embodiment 1 of the present invention.
Will be described with reference to. FIG. 1 is a first embodiment of the present invention.
FIG. 4 is a circuit diagram showing the above, and the parts from the AC overhead wire 1 to the circuit breaker 14 are the same as those of the conventional device described above.

In FIG. 1, reference numeral 16 is an integrator connected to the ACCT 12A and integrating the detected current of the ACCT 12A,
Reference numeral 17 is connected to the integrator 16 and the DCPT 13, and is a divider that divides the output of the integrator 17 by the detection voltage of the DCPT 13, 1
Reference numeral 8 is a comparator which is connected to the divider 17 and compares the output of the divider 17 with a constant value. Reference numeral 19 is a display which is connected to the output side of the comparator 18 and displays the output value of the comparator 18. .

By the way, the capacitance detecting means of the present invention is, for example, the charging resistor 1 in the first embodiment of the present invention described above.
0, short-circuit switch 11, DCPT13, ACCT12
A, integrator 16, divider 17, comparator 18, and display 1
It is composed of 9.

Next, the capacitance detecting operation of the above-described first embodiment will be described. First, when the control device for an AC electric vehicle is activated, the current for initially charging the smoothing capacitor 6 is ACCT.
12A, and this is integrated by the integrator 16 to obtain the charge amount stored in the smoothing capacitor 6. This charge amount is divided by the voltage of the smoothing capacitor 6 detected by the DCPT 13 by the divider 17 to obtain the capacity of the smoothing capacitor 6. Then, this is compared with a preset lower limit value of the capacity of the smoothing capacitor 6 by the comparator 18, and the result is displayed by the display unit 19.

As described above, the current for charging the smoothing capacitor 6 is integrated by the integrator 16 to obtain the charge amount of the smoothing capacitor 6, and this charge amount is divided by the voltage of the smoothing capacitor 6 by the divider 17. By calculating the capacity of the smoothing capacitor 6 by dividing, the capacity of the smoothing capacitor 6 can be automatically calculated. Therefore, the decrease in the capacity can be easily detected, maintenance is facilitated, and a separate capacitance meter is required. Therefore, maintenance can be performed economically.

Example 2. In the first embodiment described above, the amount of electric charge stored in the smoothing capacitor 6 is represented by AC current A.
It is obtained by integrating the detected current of the CCT 12A, but in the second embodiment, it is obtained by integrating the direct current which is the output current of the PWM converters 4 and 5.

The configuration of the second embodiment of the present invention will be described with reference to FIG. Second Embodiment FIG. 2 is a circuit diagram showing a second embodiment of the present invention. In each drawing, the same reference numerals as those in the first embodiment indicate the same or corresponding portions.

Referring to FIG. 2, in the second embodiment of the present invention,
A DC current detector (hereinafter referred to as “DCCT”) 20 provided on the output side of the PWM converters 4 and 5 is used, and the DC current is integrated by an integrator 16A connected to the DCCT 20 to smooth the smoothing capacitor 6 The amount of electric charge stored in is calculated. With such a configuration, the capacity of the smoothing capacitor 6 can be detected as in the case of the first embodiment, and the decrease in capacity can be detected.

[0018]

As described above, the control device for an AC electric vehicle according to the present invention smoothes the direct current to the converter for converting the alternating current stepped down by the main transformer into the direct current and the inverter for feeding the electric motor. Since the smoothing capacitor to be supplied and the capacity detecting means for detecting the capacity of the smoothing capacitor based on the current and voltage of the smoothing capacitor are provided, the maintenance becomes easy, and a separate capacity meter is not required. Therefore, there is an effect that the maintenance can be economically performed.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a conventional control device for an AC electric vehicle.

[Explanation of symbols]

 3 main transformer 4, 5 PWM converter 6 smoothing capacitor 7 variable voltage variable frequency inverter 8 induction motor 12A AC current detector 13 control DC voltage detector 16, 16A integrator 17 divider 18 comparator 19 indicator 20 AC current detector

Claims (1)

[Claims] 1. A converter for converting an alternating current stepped down by a main transformer into a direct current, a smoothing capacitor for smoothing and supplying the direct current to an inverter for feeding an electric motor, and a current and a voltage of the smoothing capacitor at startup. A control device for an AC electric vehicle, comprising a capacity detecting means for detecting the capacity of the smoothing capacitor based on the control means.