JPS631004B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for an electric vehicle, and particularly to a constant speed operation control device for an electric vehicle.

Conventionally, constant speed operation of electric vehicles has not been carried out except in the classical method. The classical method is generally the notch command method, in which the speed of the electric car varies widely depending on fluctuations in overhead line voltage, track slope conditions, and the magnitude of the load on the electric car, and these external conditions This requires the driver to change the notch on the electric car's main controller and frequently operate the electric car, including operating the brake valve, to keep the electric car at the desired speed. The level of skill and workload required was enormous. In addition, in the past, the driver's attentiveness and skilled driving skills were used to perform the power operation, and the brakes and other driving operations were left solely to the driver's judgment. It could not be said that there were no problems in terms of safe driving.

An object of the present invention is to simplify driving operations, reduce the driver's skill level and burden, and improve safety by avoiding conventional driver misperceptions and erroneous operations. Furthermore, the objective is to maintain accurate operating time, improve operating speed, and perform economical operation to reduce power consumption.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electric vehicle control device for controlling constant speed operation according to an embodiment of the present invention shown in FIGS. 1 and 2 will be described below. In the figure, 1 is a current control command circuit that commands the main motor current, and the command value is Ipp.
Note that a DC series motor is generally used as the main motor. Reference numeral 2 is a speed command device that commands the speed of the electric car and can be operated arbitrarily by the driver. 3
4 is a speed detector that detects the actual speed of the electric vehicle, and 4 is the command value Vp from the speed command device 2 and the speed detector 3.
Detects the deviation ΔV of the actual speed Vi, which is the output of
Vc. ) is an arithmetic circuit that outputs the value of ΔV/Vc. Reference numeral 5 denotes a current calculation circuit that calculates the product of the result of the calculation circuit 4 and the current control command value Ipp, which is usually composed of a multiplier circuit and outputs Ip which is the control command value of the actual main motor current.
7 is a constant current control circuit, which feeds back Ip calculated by the current calculation circuit 5 and the detected value I _M of the actual current detector 6 of the main motor, calculates the deviation between the two, and sets I _M as the target value. control. 8 is a phase shifter that determines the conduction time of the chopper according to the output of the constant current control circuit 7. A chopper (not shown) is controlled by the output of the phase shifter 8, and the speed of the main motor is controlled. 9 is a speed setting device that generates a preset command speed Vc, and this speed Vc influences the required speed accuracy of convergence in constant speed operation and the stability when converging to the command speed. It becomes a factor.
In other words, the smaller Vc, the higher the speed accuracy and the lower the stability. The opposite is true if Vc is large. Here, if we summarize the value of Ip again, it is expressed by the following formula.

Ip=Ipp×ΔV/Vc Next, in order to make the present invention more clear, the circuit configuration of the arithmetic circuit 4 will be described in detail with reference to FIG. In FIG. 2, numerals 1 to 3, 5, and 9 have the same functions as in FIG. 1, so their explanation will be omitted here. 10 is a subtracter that calculates the deviation value ΔV between the speed command value Vp and the actual speed Vi, and 11 is a subtracter that calculates the difference between the deviation value ΔV that is the output of the subtracter 10 and the fixed value Vc that is the output of the speed setting device 9. In a circuit that normalizes with a fixed value Vc, the output value is (Vc−
ΔV)/Vc, and this circuit outputs only positive values. Furthermore, 12 is a subtracter that subtracts the value output from circuit 11 from 1, so its output is 1-{(Vc-
ΔV)/Vc}, and as a result, the output of the subtracter 12 becomes ΔV/Vc. Here, since the normalization circuit 11 does not output the negative value, only when ΔVVc,
ΔV/Vc is a valid value. Therefore, the circuit configuration shown by 4 in FIG. 1 corresponds to 10 to 12 in FIG.

FIG. 3 shows the relationship between the speed deviation ΔV and the current control command value Ip when controlled by the circuit configuration of the present invention. In the figure, the solid line indicates the characteristic when the current command value is Ipp ₁ , and the one-dot chain line indicates the case when the current command value is Ipp ₂ . This figure shows ΔV on the horizontal axis and Ip on the vertical axis. When the speed deviation ΔV is large, the current control command value Ip is the same as the original command value Ipp output from the current control command circuit 1. , when the speed deviation ΔV becomes smaller, that is, when the actual vehicle speed Vi approaches the command speed Vp and further reaches ΔVVc, the current calculation circuit 5 calculates the current command value Ipp and the calculation circuit 4 due to the operation of the calculation circuit 4 shown in FIG. The output (in FIG. 2, the output of the subtracter 12) is multiplied by ΔV/Vc, and the current control command value Ip decreases along a straight line such that Ip=0 when ΔV=0. Here, Ip=0 means that
Since setting the main motor current I _M to 0 is the same as setting the vehicle traction force to 0, the vehicle is necessarily balanced at a speed determined by the load conditions and the slope conditions at that time. In other words, when the traction force generated at Ipp is larger than the traction force to be balanced by the vehicle, the vehicle will always move between the vehicle speed where the speed deviation ΔV becomes Vc and the command value Vp (in the range below Vc in Figure 3). ) enables balanced operation at any speed.

The circuit configuration of the present invention is characterized by: Since current control and torque control are performed continuously, extremely good results can be obtained in terms of convergence to the equilibrium speed of the vehicle.

Since it is a continuous control, high control accuracy of constant speed operation can be achieved by setting Vc.

The additional circuits of the present invention are a subtraction circuit and a multiplication circuit, which can be realized with a simple circuit.

No matter what value the original current command value Ipp is, the control start point of the current control command value Ip (speed Vc here)
are the same and the convergence point of Ip is the same, so the convergence of constant speed control is good regardless of the vehicle load conditions.

This is in addition to the effects mentioned above due to the realization of constant speed operation control. In FIG. 3, the point where Ip=0 is the same as the command speed Vp, but it goes without saying that this can be any point in relation to the control accuracy of constant speed operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an electric vehicle control device showing one embodiment of the present invention, FIG. 2 is a block diagram showing the main parts of FIG. 1, and FIG. 3 is a control of the electric vehicle control device shown in FIG. 1. FIG. 3 is a characteristic diagram showing characteristics. In the figure, 1 is a current control command circuit, 2 is a speed command, 3 is a speed detector, 4 is an arithmetic circuit, 5 is a current arithmetic circuit, 6 is a current detector, 7 is a constant current control circuit,
9 is a speed setter, 10 is a subtracter, 11 is an arithmetic circuit, and 12 is a subtracter. Note that the same reference numerals in the figures indicate the same parts.

Claims (1)

[Claims] 1. A current control command circuit that commands the current flowing to the electric motor of the electric car, a speed command that commands the speed of the electric car, a speed detector that detects the speed of the electric car, a command value of the speed command and the speed detector A first arithmetic circuit that calculates the deviation ΔV from the detected value, calculates (Vc - ΔV)/Vc with the deviation ΔV calculated by this first arithmetic circuit and a predetermined value Vc, and outputs only positive values. A second arithmetic circuit that outputs the value of ΔV/Vc by subtracting the output of the second arithmetic circuit from 1, a command value of the current control command circuit and the third arithmetic circuit It is characterized by comprising a fourth arithmetic circuit that calculates the product of the output values of the arithmetic circuits and outputs a current control command value, and controls the current of the motor by using the output of the fourth arithmetic circuit as a target value. control device for electric cars.