JPS6240957B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a DC motor control device using a chopper control device.

DC motors, especially the traction motors of electric cars, have a rated speed that is less than 1/2 of the operating speed in order to make them economical, and the maximum speed is achieved by weakening the field of the traction motor to obtain a speed higher than the rated speed. There is. For example, there is a system shown in FIG. 1 that uses a main motor having such characteristics to control an electric vehicle by a chopper. In the figure, 1 is a panda graph, 2 is a filter reactor, 3 is a filter capacitor, 4 is a main smoothing reactor, 5 is a traction motor armature, 6 is a traction motor field winding, 8 is a chopper device, and 9 is a freewheeling diode. , 10, 12 are weak field switches, and 11 is a weak field resistor.

Next, the operation will be briefly explained. At startup, the weak field switches 10 and 12 remain open, and constant current control is performed until the maximum conduction rate is reached with the entire field, and the chopper 8
When the conduction period (hereinafter referred to as conduction rate) reaches the maximum, the weak field switch 10 is turned on, and the main motor current is shunted to the weak field resistor 11 and the field winding 6.
Constant current is controlled by the field rate determined by the resistance ratio of both,
Drive at high speed. However, when transitioning from full field control to weak field control, a step in torque inevitably occurs.
The weak field contactor is multi-staged in two and three stages to compensate for sudden changes in torque.

As described above, the conventional field control system has the drawback that a step difference in torque occurs and a multi-stage switch is required to compensate for this step.

This invention has been made in view of the above points, and enables continuous control of the magnetic field. This is to control the phase of a thyristor connection body consisting of a reverse conduction thyristor or a reverse blocking thyristor and a diode connected in antiparallel to continuously change the field rate.

The system of the embodiment of this invention shown in FIGS. 2 to 6 will be explained below. Components with the same symbols in the drawings have the same functions, so their explanation will be omitted.

FIG. 2 shows an embodiment in which the present invention is applied to a parallel arc-extinguishing type repulsion pulse commutation circuit. Reference numeral 13 denotes a reverse conduction thyristor, which is a thyristor connection body that is connected in parallel to the main motor field winding 6 and performs phase control to continuously change the field rate;
1 is a main thyristor, 16 is a commutating reactor, 17 is a commutating capacitor, 18 is a diode, and 19 is an auxiliary thyristor, and 13, 14, 16 to 19 constitute a chopper. Next, the operation will be explained. First, the reverse conduction thyristor 13 is turned off, and then activated with a full magnetic field to perform constant current control. When the chopper reaches the maximum conduction rate, the conduction rate of the chopper is fixed and the thyristor 13 is controlled in phase. Phase control may be performed by comparing the constant current control set value (hereinafter referred to as current limit value) and the main motor current, and using this deviation. That is, immediately after the chopper reaches its maximum conduction rate, if the thyristor 13 is fired just before the chopper turns off, the field current is shunted to the current path of the thyristor 13. Next, a pulse enters the auxiliary thyristor 19,
The resonant current of the commutating reactor 16 and commutating capacitor 17 flows through the diode 18 and the auxiliary thyristor 19, and the reversing current passes through the main thyristor 14 and thyristor 13, turning off the thyristors 13 and 14, and turning off the chopper. As the speed of the traction motor increases, the traction motor current tends to decrease, so
The firing timing of the thyristor 13 is automatically controlled, the conduction rate is increased, and weak field control can be performed continuously.

FIG. 3 shows an embodiment in which the present invention is applied to a series arc-extinguishing type repulsion pulse type commutation circuit. Reference numeral 15 indicates an auxiliary thyristor, and the other parts are the same as in FIG. The operation is almost the same as that shown in Fig. 2, but when the main motor is operated in full field, an auxiliary thyristor 15 is installed at the gate of thyristor 13 to prevent the commutated current for chipping off from flowing into the field 6. It is necessary to insert an off pulse at the same timing as the gate.

FIG. 4 shows a regenerative brake circuit using the same commutation method as in FIG. All the symbols are the same as in FIG. The operation of the thyristor 13 is the same as that during power running, so a description thereof will be omitted.

FIG. 5 shows an embodiment in which the present invention is applied to a single-phase dual-type power running circuit using the same commutation method as in FIG. 3. In the figure, the number with a at the end indicates the first group, and the number with b indicates the second group.

FIG. 6 shows an embodiment in which the circuit shown in FIG. 5 is applied to a regenerative brake circuit. All numbers in the figure are the same as in FIG.

Although this invention has been described only with respect to the parallel arc-extinguishing repulsion pulse method and the series arc-extinguishing repulsion pulse method, it is not limited to these methods and can be applied to other commutation methods. Further, the reverse conduction thyristor is drawn to simplify the drawing, and it goes without saying that a reverse blocking thyristor and a diode connected in antiparallel can also be applied.

As described above, according to the present invention, (A) weak field continuous control is possible by simply using a thyristor element in place of the conventional weak field switch, and the riding comfort of the vehicle can be improved.

(B) As with conventional constant current control, only the timing of ignition of the thyristor needs to be controlled based on the deviation between the current limit value and the main circuit current, so continuous control can be achieved with simple control.

(C) The main thyristor and the thyristor connection body can be turned off reliably by the oscillating current of the commutation circuit, and highly reliable control can be performed.
It has the following characteristics.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional weak field control power running circuit, and Fig. 2 is a circuit diagram showing an embodiment of a power running circuit to which the present invention is applied, which performs weak field continuous control in a parallel arc-extinguishing repulsion pulse commutation system. Figure 3 is a circuit diagram showing an embodiment of a power running circuit in which the present invention is applied to a series arc-extinguishing type repulsion pulse commutation method, and Figure 4 is a circuit diagram showing an embodiment of a power running circuit in which the method of Figure 3 is applied to a regenerative brake circuit. Figure 5 is a circuit diagram showing an example of the method shown in Figure 3.
FIG. 6 is a circuit diagram showing an embodiment of a power running circuit in which the present invention is applied to a heavy-duty system, and FIG. 6 is a circuit diagram showing an embodiment in which the system of FIG. 5 is applied to a regenerative brake circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts. In the figure, 4 is a main smoothing reactor, 5 is a DC motor armature, 6 is a DC motor field winding, 8 is a chopper device, 13 is a thyristor connection body, and 14 is a main thyristor.

Claims (1)

[Claims] 1. A DC motor comprising a DC motor, a main smoothing reactor connected in series with the DC motor, and a chopper circuit connected to the DC motor and having a main thyristor that controls the current flowing through the DC motor. In the control device, a reverse conduction thyristor that is connected in parallel with the field winding of the DC motor and in series with the main thyristor and controls the current flowing into the field winding of the DC motor, and the main thyristor. a commutation circuit common to the reverse conduction thyristor and the main thyristor, which is connected to a series circuit with the reverse conduction thyristor to form a closed circuit, and extinguishes both the reverse conduction thyristor and the main thyristor at the same time; A DC motor control device characterized by: