JP4450469B2 - Electric vehicle control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric vehicle control apparatus for driving an induction motor that uses both regeneration and a power generation brake system, and more particularly to an electric vehicle control apparatus that can secure an electric brake force in a high-speed region.
[0002]
[Prior art]
FIG. 3 is a diagram showing a main circuit connection diagram of the electric vehicle control device.
In the drawing, a pantograph 1 that collects current from an overhead wire is connected to a closing circuit 12 including a high-speed circuit breaker 2, a first unit switch 3, and a second unit switch 4, and the first resistor 5 is connected to the second unit switch 4. Are connected in parallel.
A filter reactor 6 and a filter capacitor 9 are connected in series to the second unit switch 4 of the input circuit 12. A series circuit of a chopper 7 and a second resistor 8 connected in parallel to the filter capacitor 9 and a three-phase AC output are provided. An inverter circuit 10 is connected. An induction motor 11 is connected to the three-phase alternating current side of the inverter circuit 10, and when the electric vehicle is powered, the induction motor 11 is driven and the electric vehicle runs.
[0003]
The control circuit 13 of the closing circuit 12 controls the first unit switch 3 and the second unit switch 4 as follows.
When the voltage of the filter capacitor 9 is low, the second unit switch 4 is not turned on, the first unit switch 3 (the high speed circuit breaker 2 is always turned on) is turned on, and the filter capacitor 9 is charged via the first resistor 5. Is done.
Thereafter, the second unit switch 4 is turned on under the condition (VFC condition) that the voltage of the filter capacitor 9 has increased to 80% or more of the overhead line voltage. The second unit switch 4 remains on while this condition is satisfied.
[0004]
FIG. 4 shows the input logic of the second unit switch 4 of the input circuit 12. In FIG. 4, AND is an AND gate, HB is the high-speed circuit breaker 2, LB1 is the first unit switch 3, LB2 is the second unit switch 4, and when the VFC condition is satisfied, [filter capacitor voltage VC] / [overhead wire] Voltage VL] is 80% or more.
As shown in FIG. 4, LB2 (second unit switch 4) is turned on when [HB (high speed circuit breaker 2) is on], [LB1 (first unit switch 3) is on] and [when VFC condition is satisfied]. . That is, until the voltage of the filter capacitor 9 rises to 80% or more of the overhead line voltage, the second unit switch 4 is opened to suppress the charging current of the filter capacitor 9, and the voltage of the filter capacitor 9 is 80% or more of the overhead line voltage. The second unit switch 4 is closed and the first resistor 5 is bypassed.
[0005]
The electric vehicle control apparatus shown in FIG. 3 operates as follows during braking.
At the time of braking, the induction motor 11 operates as an induction generator, and AC power generated by the induction generator is converted into direct current by the inverter 10 and another load (for example, close to the load) connected to the overhead line through the pantograph 1. It is consumed by other electric vehicles that travel. Such a brake control system is called a regenerative brake system.
On the other hand, when the electric vehicle travels in a secluded line area or when it is driven early in the morning and late at night, when the other load connected to the overhead line is small, the electric power generated by the induction motor 11 cannot be consumed. Therefore, the chopper 7 is operated to cause the second resistor 8 to consume current, and the electric brake is continued. Such a method of consuming brake power with a load mounted in an electric vehicle is called a power generation brake method.
[0006]
[Problems to be solved by the invention]
By the way, in the above-described conventional regeneration and power generation braking system, the braking force at high speed is insufficient with the characteristics that have been determined based on power running so far.
As a conventional example, the characteristic of insufficient braking force at high speed is shown by a two-dot chain line in FIG.
In a vehicle using an electric power regenerative brake, the maximum DC voltage is suppressed by the overhead wire voltage limit, and as shown in FIG. 5, it is difficult to obtain a necessary braking force at a high speed of, for example, 80 km / h or higher. (The conventional constant braking force speed range was assumed to be 80 km / h or less.)
For this reason, the insufficient braking force is supplemented by a mechanical air brake or the like that operates the air cylinder using compressed air as a medium and presses the friction material against the wheel tread or the disk to obtain the braking force by the frictional force. It was general.
An air brake or the like that uses friction generates heat as brake energy. Moreover, since the brake power is proportional to the braking force and the traveling speed, it becomes a very large value at a high speed.
For this reason, there has been a problem that the frictional heat between the brake shoe and the wheel tread causes the brake shoe and the wheel tread to be worn parts, increasing the chance of daily inspection and maintenance.
[0007]
The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide an electric vehicle control device capable of expanding the electric brake force in a high speed range. .
[0008]
[Means for Solving the Problems]
The electric vehicle control apparatus according to the present invention solves the above-described problems as follows.
(1) At the time of electric braking in a high speed range, by opening the unit switch of the closing circuit, the electric brake is operated via a resistor connected in parallel to the unit switch. Then, after braking from high speed, the unit switch is turned on again when the speed drops to the conventional constant braking force speed range.
(2) At the time of braking in a high speed region, the control circuit opens the unit switch of the closing circuit and changes the operating point voltage set value of the chopper circuit to a high value.
[0009]
By configuring as in (1) above, the DC voltage of the inverter input circuit is raised by a voltage determined from the regenerative current flowing through the resistor connected in parallel to the unit switch and the resistance value during electric braking in the high speed range. Can do.
As a result, the three-phase AC voltage of the induction motor rises, and the electric brake force can be obtained at a high speed without increasing the brake current. Further, it can be used without changing the special main circuit configuration and without increasing the capacity of the current induction motor and inverter circuit.
Furthermore, after braking from a high speed, when the speed drops to the conventional constant braking force speed range, the unit switch is turned on again, so that the electric brake can be continued according to the conventional brake characteristics.
Moreover, by configuring as in the above (2), the power generation braking force at high speed can be improved without changing the special main circuit configuration as in the above (1).
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of an electric vehicle control apparatus according to an embodiment of the present invention. The main circuit connection is the same as that shown in FIG. 3, and in this embodiment, the input logic of the second unit switch 4 in the control circuit 13 for controlling the input circuit 12 is different from those in FIGS. is doing. Further, the set value of the operating point voltage of the chopper control circuit 14 is changed to a high value by the output of the control circuit 13. Thereby, in this invention, an electric brake area | region can be expanded.
[0011]
In this embodiment, the operation of the second unit switch 4 for the purpose of charging the filter capacitor 9 is the same as that of the conventional example. That is, when the voltage of the filter capacitor 9 is low, the first unit switch 3 is turned on, the second unit switch 4 is not turned on, and the filter capacitor 9 is charged via the first resistor 5. When the voltage of the filter capacitor 9 rises to 80% or more of the overhead line voltage, the second unit switch 4 is turned on.
In addition to this condition, in this embodiment, the second unit switch 4 is opened and the first resistor 5 connected in parallel is energized and regenerated through the pantograph 1 during braking in the high speed region. Further, the operating point of the chopper 7 is increased.
[0012]
FIG. 2 shows the input logic of the control circuit 13 of this embodiment.
In the figure, AND is an AND gate, HB is the high-speed circuit breaker 2, LB1 is the first unit switch 3, LB2 is the second unit switch 4, and when the VFC condition is satisfied, [filter capacitor voltage VC] / [overhead wire] When the voltage VL] is 80% or higher and the speed condition is satisfied, it is a case where the speed is equal to or higher than the constant braking force speed.
As shown in FIG. 2, LB2 (second unit switch 4) is turned on [HB (high speed circuit breaker 2) on], [LB1 (first unit switch 3) on] and [when VFC condition is satisfied] When the speed condition is satisfied, the second unit switch 4 is opened.
Further, after braking from a high speed, when the speed drops to the conventional constant braking force speed range, the speed condition is not satisfied and the second unit switch 4 is closed. For this reason, the electric brake is continued according to the conventional brake characteristics.
[0013]
In the present embodiment, the second unit switch 4 is opened as described above during the regenerative braking operation when the speed condition is established. For this reason, the voltage determined from the current flowing through the first resistor 5 and the resistance value increases the input DC voltage of the inverter circuit 10, and the voltage of the induction motor 11 as the output increases.
Generally, due to the characteristics of the induction motor, when the voltage rises, the magnetic flux increases proportionally and the torque of the main motor increases. For this reason, the regenerative braking force can be increased.
Further, when the second unit switch 4 is open during braking in the high speed region, the operating point voltage set value of the chopper 7 is changed to a high value. Thereby, the braking force at the time of power generation braking can be increased.
[0014]
【The invention's effect】
As described above, in the present invention, at the time of braking in the high speed region, the input DC voltage of the inverter circuit 10 is increased by opening the unit switch of the closing circuit, so that a new main circuit configuration is not particularly added. The electric brake force can be increased by the same main circuit connection as in the prior art.
For this reason, in the conventional high-speed region, mechanical air brakes or the like that are supplementary braking force are reduced or unnecessary, and daily inspection and maintenance of brake shoes and wheel treads are greatly reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
FIG. 2 is a diagram showing the input logic of a second unit switch in the embodiment of the present invention.
FIG. 3 is a diagram showing a main circuit configuration of the electric vehicle control device.
FIG. 4 is a diagram showing the input logic of a second unit switch in a conventional example.
FIG. 5 is a diagram showing a characteristic that a braking force is insufficient at a high speed.
[Explanation of symbols]
1 Pantograph 2 High-speed circuit breaker (HB)
3 First unit switch (LB1)
4 Second unit switch (LB2)
5 first resistor 6 filter reactor 7 chopper 8 second resistor 9 filter capacitor 10 inverter circuit 11 induction motor 12 closing circuit 13 closing control circuit 14 chopper control circuit

Claims (2)

A closing circuit composed of a high-speed circuit breaker connected in series to the overhead wire, a unit switch, and a resistor connected in parallel to the unit switch;
An inverter circuit that converts the DC power supplied from the overhead line via the charging circuit and supplies three-phase AC power to the induction motor for driving an electric vehicle;
An electric vehicle control device comprising a chopper circuit in which a switching element and a resistor are connected in series in parallel with a filter capacitor,
The control circuit that controls the unit switch of the closing circuit opens the unit switch of the closing circuit and applies the brake current through the resistor of the closing circuit to regenerate the brake current when braking in the high speed region. An electric vehicle control device. 2. The electric vehicle control device according to claim 1, wherein the control circuit opens the unit switch of the closing circuit and changes the operating point voltage set value of the chopper circuit to a high value during braking in a high speed region.

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