JPS5911242B2 - Electric vehicle chip control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric vehicle chopper control device that regeneratively brakes an electric vehicle using a chopper device.

Generally, when performing regeneration control using a chopper device, stable control is possible only in the region where the traction motor terminal voltage is lower than the power supply voltage. In the high speed range, where the motor speed exceeds 5, a brake resistor BR is inserted in series with the main motor armature A, and regenerative braking is applied from higher speeds by the voltage drop.

However, if the brake resistor BR is permanently connected, the loss due to heat generation will be large and the regeneration efficiency will be reduced10, and the capacity of the brake resistor BR itself will also be large, so a resistor shorting switch s is installed to ensure that the main motor terminal voltage is A method was considered to increase the regeneration efficiency by turning on this short-circuit switch s when the voltage drops below the voltage, but at the moment when the brake resistor BR is short-circuited, the filter capacitor C_F is transiently reduced. The voltage jumps up, and an abnormally high voltage is applied to the chopper device CH.
It has been difficult to realize resistor short-circuit control because there is a risk that the resistor may be destroyed. In addition, in Fig. 1, P is a bar 20 fern graph,
L_F is a filter reactor, D_F is a backflow blocking diode, MSL is a main smoothing reactor, and _F is a main motor field winding. The present invention has been made in view of these points, and it is an object of the present invention to provide an electric vehicle chopper control device that can perform 25-resistance short-circuit control without causing the voltage rise of the filter capacitor and has a high regeneration rate.

The present invention will be explained below using FIGS. 2 to 4.

FIG. 2 is a circuit diagram 30 showing an embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate the same or corresponding parts. TH is a reverse blocking thyristor, and il, i2, and 13 are currents flowing through each line. FIG. 3 is a waveform diagram showing the signals of each part in FIG.
_F pulse, THoN is thyristor ON pulse, i,,
i2 and i3 are the currents 11, i2, and
It is i3. FIG. 4 is a notch curve diagram, where 5 is a notch curve when the brake resistor BR is inserted, and 6 is a notch curve when the brake resistor BR is short-circuited. Next, the operation will be explained.

Now, in a high speed range where the main motor terminal voltage exceeds the power supply voltage, all the current regenerated to the overhead wire flows through the brake resistor BR without issuing a gate pulse of the reverse blocking thyristor TH. When the speed decreases and reaches point a in Fig. 4, the thyristor 0N pulse THON is generated in front of the chopper 0N pulse CHON as shown in Fig. 3, and its conduction rate is controlled. The apparent resistance value is changed continuously between A and B to suppress the rise in the filter capacitor CF voltage. The current shown in Figure 3! 1 with a current waveform of 1
In the mode 2 to 2, the slope of the current 11 becomes Dil/Dt=EM/L during the period when the chopper device CH is ON. However, EM is the main motor terminal voltage, L is the inductance of the main smoothing reactor MSL, and other circuit constants are ignored. In modes 2 to 3, the blocking thyristor CH is OFF and the reverse blocking thyristor TH is also OFF.
During this period, the filter capacitor CF voltage + brake resistor BR voltage drop exceeds the main motor terminal voltage, so the current shows a decreasing trend, and its slope is Dil.
/Dt=-(Ec+Ril-EM)/L.

However, Ec is the capacitor voltage, EM is the main motor terminal voltage, and R is the resistance value of the brake resistor BR. In modes 3 to 4, the current 11 is during the period when the Chiyotsuba device CH is 0FF but the reverse blocking thyristor TH is 0N, and it is assumed that the main motor terminal voltage EM is higher than the capacitor voltage Ec. It shows an increasing trend, and Di/D
t=(EM-Ec)/L.

At point 4 in FIG. 3, a chopper ON pulse is applied, but reverse bias 5 is applied to the reverse blocking thyristor TH, which instantly turns it off. Therefore, the reverse blocking thyristor TH does not require an arc extinguishing thyristor or a commutation circuit. When the speed drops to point b on the notch curve in Figure 4, the traction motor terminal voltage EM becomes lower than the capacitor voltage Ec, so there is no need to insert the brake resistor BR, and the reverse blocking thyristor TH is constantly at 0N. When a pulse is applied, it functions in the same way as a backflow blocking diode DF, and performs exactly the same circuit operation as the conventional one. Therefore, in the region above point a on the notch curve, no pulse is applied to the reverse blocking thyristor TH, and the conductivity is maintained from 0 to 1 between points a and b, and in the region below point b, it is 0.
The N pulse is continuously applied. In this way, the brake resistor BR is inserted in the high speed range, and the brake resistor BR is short-circuited in the medium and low speed range, and resistance vernier control is performed at the joint (between points a and b), so the resistance of the brake resistor BR is The value changes continuously, and there is almost no jump in the filter capacitor CF voltage. Therefore, stable regenerative brake control is possible over a wide range from high speed to low speed. Although the above description has been made regarding a single-phase chopper device, the present invention can also be applied to a chopper device with two or more phases.

Fig. 5 shows an application of the present invention to a two-phase chopper device, in which the same reference numerals as in Fig. 2 indicate the same parts, and the numerals 1 and 2 indicate the 1-phase side and 2 the 2-phase side, respectively. The effect is the same as described above, so the explanation will be omitted. As described above, the present invention connects a thyristor in parallel to the brake resistor, makes the thyristor non-conductive in the high speed range, gives an on pulse to the thyristor before generating the on pulse of the chopper device in the medium and low speed range, and conducts the thyristor. Since the rate is controlled, there is no jump in the filter capacitor CF voltage, and regenerative braking control is performed stably from high speed to low speed.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing a conventional electric vehicle chopper control device.
Fig. 2 is a circuit diagram showing an embodiment of the present invention, Fig. 3 is a signal waveform diagram of each part of Fig. 2, Fig. 4 is a notch curve diagram, and Fig. 5 is a notch curve diagram.
The figure is a circuit diagram showing another embodiment of the invention. In the figure, LF is a filter reactor, CF is a filter capacitor, TH is a thyristor, BR is a brake resistor, DF is a reverse blocking diode, CH is a chopper device,
MSL is the main smoothing reactor, and A is the main motor armature.

Claims (1)

[Claims] 1 Filter reactor L_F and filter capacitor C
A chopper for regenerative braking of an electric vehicle, comprising a filter circuit consisting of a chopper device CH, a main smoothing reactor MSL, and a main motor and connected to the filter circuit through a backflow blocking diode D_F. In the control device, a brake resistor BR is inserted in series with the backflow blocking diode D_F, and a thyristor is connected in parallel with the backflow blocking diode D_F and the brake resistor BR, and in the same direction as the diode D_F. In the range, the thyristor is made non-conducting, and in the medium and low speed range, an on-pulse is given to the thyristor before the on-pulse generation of the chopper device, and the conduction rate of the thyristor is controlled, so that the resistance BR is equivalently continuously changed. An electric vehicle chopper control device characterized in that: