JPS6032412B2 - electric car control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improving the power running performance of an electric vehicle that uses a chopper for speed control, and particularly to improving ride comfort when the chopper is short-circuited.

The main circuit connections during power running of an electric vehicle using the conventional general chopper control method are as shown in FIG.

In the figure, 1 is a pantograph, 2 is a main motor, 3 is a smoothing reactor, 4 is a freewheel diode, 5 is a chopper, and 6 is a contactor. In the chopper control system with such a circuit configuration, when the chopper 5 is on, a main circuit current flows through the pantograph 1 - the main motor 2 - the smoothing reactor 3 - the chopper 5.

When Chotsuba 5 is turned off, the main circuit current is main motor 2 - smoothing reactor 3 - freewheel diode 4
flows like. In this way, the average value of the main circuit current is controlled by controlling the on-off cycle of the chopper, but as the back electromotive force of the traction motor 2 increases as the acceleration increases, the average voltage at the terminals of the traction motor 2 must be increased. It becomes difficult to obtain an accelerating current during the period. Therefore, in order to increase the terminal voltage of the main motor 2 as the back electromotive force increases, the on time of the chopper 5 must be made extremely longer than the off time. However, since a general chopper must store commutated energy during the chopper's off time, there is a limit to how short the absolute time of the off time can be. If the off time is shortened beyond the limit, the commutation circuit of the chopper 5 will not be able to sufficiently store the energy necessary for commutation, resulting in commutation failure and making it impossible to turn off the chopper 5. This limit value, ie, the state where the on-time reaches a maximum, is called the maximum conduction rate. This maximum conductivity is generally 0.95
~0. It is about the size of a mackerel. If the chopper 5 continues to be turned on and off in this state, the voltage drop due to chopping (0.02 to 0.05) and the resistance due to the smoothing reactor 3 will increase compared to the point corresponding to the end of linear acceleration in the conventional resistance control method. The voltage applied to the main motor 2 is reduced by the loss.

Needless to say, it is desirable not only from the acceleration characteristics but also from the thermal margin of the chopper 5 and the smoothing factor 3 to apply the full voltage to the main motor 2 to allow free acceleration. For this purpose, measures are taken such as setting the chopper 5 to 100% duty or short-circuiting the smoothing reactor 3 with a contactor 6.

However, depending on the timing of turning on the contactor 6, a sudden increase in the power of the main motor may cause a sudden change in torque, which may impair riding comfort.

This will be explained with reference to FIG.

FIG. 2 shows the speed characteristic curve.

In the same figure, the maximum conduction rate (for example, 0.98) of the camellia
, the characteristic port has a flow rate of 1 (duty of chopper 5 is 100)
%), characteristic C is open circuit of contactor 6 (chopper 5 and smooth IJ
This is the characteristic when factor 3 is short-circuited. In addition to these characteristics, characteristics in a state where the chopper 5 is short-circuited with another contactor may also be considered, but these are omitted. When the main motor 2 is accelerated and reaches the maximum conduction rate, this is detected, the duty of the chopper 5 is set to 100%, and the contactor 6 is turned on.If these commands are issued at the same time, the current will change from point P to point Q. Pass through and reach point R. In other words, the current increases rapidly from point P to point R,
As a result, the torque changes rapidly, resulting in poor riding comfort. The present invention has been made in view of the above, and its purpose is to reduce the sudden increase in current when the contactor that short-circuits the smooth reactor and chopper is turned on, and to suppress sudden changes in torque so as not to impair riding comfort. The purpose of the present invention is to provide an electric vehicle control device that is designed for use in electric vehicles.

The feature of the present invention is that the duty of the chopper is
is set to 100%, and the contactor is closed when the traction motor accelerates and the traction motor current has a constant relationship with the current command value.

The present invention will be explained in detail below with reference to an embodiment shown in FIG. In Fig. 3, the same symbols as in Fig. 1 indicate the same things, 7 is the current command circuit for the traction motor current command value IMs, 8 is the comparison multiplier, 9 is the phase shifter, and 10 is the maximum conduction rate. Detector, 11 is an inhibitor circuit, 12 is a timer, 13
14 is a DC current transformer, and 14 is a current detection circuit for the main motor current IM.

In this configuration, the comparison intensifier 8 compares the current command value IMs commanded by the current command circuit 7 and the main motor current IM from the current detection circuit 14 inputting the output of the DC current transformer 13. Comparison multiplier 8 multiplies the deviation with a predetermined gain, provides a time delay necessary for stabilizing control, and applies it to phase shifter 9. The phase shifter 9 determines the phase according to the output of the comparator multiplier 8 and gives an on-off command to the chopper 5. Therefore, the main motor 2 is accelerated by constant current control. The maximum conductivity detector 10 monitors the output of the phase shifter 9 and produces an output when the phase reaches a maximum. However,
The off command for chopper 5 given from phase shifter 9 is blocked by inhibit circuit 11 . Therefore, Chotupa 5
becomes 100% duty. On the other hand, when the maximum flow interruption rate detector 10 produces an output, the timer 12 is started. Then, after a preset period of time, an output is generated and the contactor 6 is closed. The time limit of the timer 12 is set as follows. That is, since the acceleration at point P in Fig. 2 is clear, the speed at point S on the characteristic curve can be determined by how much the current increment from point P, that is, the current command value IMs, is suppressed, and the time can be calculated from the acceleration. Set. The time limit of the timer 12 is approximately 1 second or less. In this way, Chiyotsupa 5
After setting the duty to 100%, in this state, it accelerates from point Q and detects that it has reached point S, and then turns on contactor 6. Therefore, the sudden increase in current when turning on contactor 6 occurs at point S. This is the change from to point T.

Therefore, in the slave, the change in the traction motor current IN when the contactor 6 is turned on is from point P to point R, but according to the present invention, the change in traction motor current is from point S to point T. can be significantly reduced.

As a result, the change in torque can be suppressed to the amount of current change from point S to point T, and riding comfort can be significantly improved. Here, since the acceleration time from point Q to point S is approximately 1 second as described above, there is no difference from the thermal margin of the chopper 5 and smoothing reactor 3 compared to the case of simultaneous injection at point P.

Furthermore, in FIG. 3, everything other than the timer 12 is necessary for conventional constant current control, and simply adding the simple timer 12 can have a great effect on improving ride comfort.

Next, in one embodiment of FIG. 3, the duty of Chotsuba 5 is set to 1.
I turned on the contactor 6 after a certain period of time after setting it to 00%, but
Even if it is detected that the main motor current has decreased to a certain value and the contactor 6 is turned on, the comfort can be similarly improved.

FIG. 4 is a block diagram showing an embodiment in this case.

In FIG. 4, the same symbols as in FIG. 3 indicate the same parts, 15 is a coefficient unit, and 16 is a comparator. In this configuration, constant current control is performed as in FIG. 3, and when the maximum conduction rate detector 10 detects the maximum conduction rate, the coefficient unit 15 is activated.

The coefficient unit 15 determines the S point in FIG. 2, and determines to what extent the change in the main motor current is suppressed relative to the current command value 1Ms. The output of the coefficient unit 15 and the output IM of the current detection circuit 14 are compared by a comparator 16, and when it is detected that the main motor current IM has decreased to a predetermined value with respect to the current command value IMs, the contactor 6 is turned on. As a result, the amount of change in the main motor current can be reduced, and the riding comfort can be improved.
In the embodiment shown in FIG. 4, a coefficient multiplier 15 is used, but when the maximum conductivity detector 10 generates an output, the comparator 16 is activated, and the output of the comparator 16 becomes a predetermined value. The same thing can be done even if the contactor 6 is turned on when the temperature is inside.

As explained above, according to the present invention, the duty of the chopper is set to 100% in order to apply full force pressure to the main motor at the end of acceleration of an electric vehicle whose speed is controlled by a chopper, and a contactor is used to short-circuit the chopper and the smoothing reactor. Since the amount of change in the main motor current at the time of turning on can be reduced and the change in torque can be suppressed to a small level, riding comfort can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a power running main circuit connection diagram of an electric vehicle using chopper control, Fig. 2 is a speed characteristic curve diagram, Fig. 3 is a block diagram showing one embodiment of the present invention, and Fig. 4 is another embodiment of the present invention. FIG. 2 is a block diagram illustrating an example. Explanation of symbols 2... Main motor, 3...
Smooth reactor, 5...Chopper, 6...
... Contactor, 9... Phase shifter, IM...
Main motor current, 1Ms... Main motor current command value. Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A main motor, a chip that controls the main motor,
The device includes a control device for controlling the conduction rate of the chopper, a smoothing reactor for smoothing the current of the main motor, and a contactor for short-circuiting the chopper and the smoothing reactor, wherein the conduction rate of the chopper is set to a predetermined value. a first means for setting the duty of the tipper to 100% when the duty becomes 100%;
An electric vehicle control device comprising: second means for closing the contactor when the current of the main motor reaches a predetermined relationship with the current command value after the tipper is set to 100% duty. 2. The device according to claim 1, wherein the second means closes the contactor a predetermined time after the first means sets the tipper to 100% duty. Electric vehicle control device.