JPS6016807B2 - Electric car control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for an electric vehicle, and more particularly to a control device for an electric vehicle that is optimal for performing good notch stop and re-powering control during power running in a vehicle using an induction motor.

Figure 1 is a diagram showing the general characteristics of an induction motor.
As is well known, when a conduction motor is used to drive an electric vehicle, it is common to maintain a constant slip frequency fs in Figure 1 and control the current constant due to the need for constant torque control. It is carried out in

FIG. 2 shows an example of a control circuit that realizes such control characteristics. That is, in order to keep the slip frequency of the induction motor 1 constant, a pulse generator 2 is directly connected to the induction motor 1, and this output signal is converted into f-V to generate a voltage corresponding to the rotation speed of the induction motor 1. - A voltage conversion circuit (f-V converter) 3, an adder 4 that adds the output of the f-V converter 3 and the slip frequency pattern SP, and an inverter that supplies power to the induction motor 1 using the voltage of this addition result. Frequency control block 6 that controls the frequency of 5
is provided.

In addition, the current flowing through the induction motor 1 is detected by the current transformer 7, and if this value exceeds the current pattern IP even slightly,
Comparator 8 generates an output signal, and voltage control block 9 operates to reduce the output voltage of inverter 5. On the other hand, when driving an electric car, it is common to adjust the speed of the electric car according to the driver's operation of a master controller. If there is no inverter, the output frequency of the inverter 5 will always be higher than the rotational frequency of the induction motor 1 by the amount of the slip frequency, so the speed will increase indefinitely.

For this purpose, a frequency limiter 10 may be provided to suppress the increase in the frequency of the inverter 5, and the maximum limit value of the frequency may be changed according to the position of the handle of the master controller. However, in this case, when re-operating from a high speed such as during re-powering after acceleration, the master controller 11 will always pass through a low notch, so the inverter 5 will always start operating from a low frequency. There was an inconvenience that the motor was initially in a regenerative state (as is well known, a regenerative state in which a voltage of a frequency lower than the rotational single frequency is applied to the induction motor) rather than power running. An object of the present invention is to provide an electric vehicle that can perform good speed control during power running by controlling the slip frequency of a driving induction motor. The present invention sets a frequency limit value according to the position of each handle of the mascon, and controls the rotation frequency of the induction motor so that the signal corresponding to the rotation speed of the induction motor, for example, the output frequency, does not exceed these set values. When the limit value specified by the master controller is exceeded, a value proportional to the amount exceeded is subtracted from the slip frequency, making it possible to perform good notch stop control and repowering control.

FIG. 3 is a block diagram showing an embodiment of the present invention.

In this embodiment, the frequency control block 6 in the apparatus shown in FIG.
This configuration is a modification of the input circuit shown in FIG. 1, in which a subtracter 12, a limiter 13, a diode 14, a /ch stop circuit 16, and a comparator 15 are newly added. That is, when the output voltage of the frequency-voltage converter 3 exceeds the voltage fP set by the mask controller 11 and the notch stopper circuit 16, the comparator 15 outputs a positive output according to the amount exceeded, and the slip frequency pattern It is subtracted from SP by the subtracter 12. The output of the subtracter 12 is applied to the adder 4 via a limiter 13 and a diode 14, respectively. In this case, the reason for inserting the limiter 13 is to limit the maximum value of the slip (not necessary if the signal SP itself is limited), and the reason for using the diode 14 is to limit the maximum value of the slip.The reason for using the diode 14 is to limit the maximum value of the slip. This is to prevent backflow. Other circuit operations are the same as in the case of FIG. With this configuration, the slip frequency added to the rotational speed of the induction motor (output of the f-V converter 3) is continuously adjusted, so that the output frequency of the inverter 5 is always equal to the rotational frequency of the transfer motor 1 during power running. Since this does not occur, even when re-powering after acceleration, there is no initial regeneration state, and smooth operation is possible. In particular, since the slip frequency is continuously reduced in accordance with the amount of excess speed, the generated torque changes smoothly. As explained above, according to the present invention, even when repowering after acceleration, the slip frequency of the induction motor does not become negative, and the slip frequency can be continuously changed from zero to the set slip frequency, and the motor Since the torque can also be changed continuously, smooth electric vehicle operation is possible.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram showing general characteristics of an induction motor, FIG. 2 is a block diagram showing a conventional electric vehicle control device, and FIG. 3 is a block diagram showing an embodiment of the present invention. 1...Induction motor, 2...Pulse generator, 3
...Frequency-voltage conversion circuit, 4... Adder, 5
...Inverter, 6...Frequency control block, 11...Mascon, 12...
Subtractor, 13...Limiter, 14...Diode, 1
5... Comparator, 16... Notch stop circuit. Leopard l figure Tsutomu Z figure 3 figure

Claims (1)

[Claims] 1. In an electric vehicle control device that controls a driving induction motor using an inverter that generates an AC output of variable voltage and variable frequency based on a slip frequency pattern, Compare the first signal with a second signal preset corresponding to the operating position of the main controller, and when the first signal exceeds the second signal, output according to the amount exceeded. Comparing means for generating a signal, calculating means for reducing the slip frequency pattern of the induction motor by the output of the comparing means, and adding or subtracting the output of the calculating means from the first signal to obtain the frequency pattern of the inverter. A control device for an electric vehicle, characterized by comprising: means.