JPS6016806B2 - Electric motor control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor control device that performs regenerative braking control using a chopper by inserting a resistor in series with the motor.

FIG. 1 shows a conventionally known electric motor control device, in which 1 is a contact wire, 2 and 3 are a filter actor and a capacitor, respectively, 4 is a smoothing reactor,
5 is the motor field winding, 6 is the motor armature, 7 is the resistance, 8
indicates a short-circuit contactor with a resistor 7, 9 indicates a chopper device, and 10 indicates a diode that prevents short-circuiting of the power supply when the chopper device 9 is on, and regenerates the motor current to the power supply on the overhead contact line 1 side when it is off. These components form a chopper regenerative brake circuit.

Further, 11 is a current detector for the motor current IM, and 12 is a voltage drop IMR across the resistor 7 from the motor voltage BN (the resistance value of the resistor 7 is R).

) is a voltage detector, 13 is a voltage detector of the voltage Vd across the filter capacitor 3, 14 is a current control section, 15 is a current control section, 16 is a comparison amplifier, 17 is a function generator, 18 to 20 is a first-order delay element, 21 is a phase shifter, 2
2 is a current command value input terminal. The output of the voltage detector 13 becomes a voltage V'cf proportional to the equivalent power supply voltage Vd (1-ym) taking into account the minimum current conductivity ym of the chopper 9. In the voltage control section 14, the output voltage V'c of the voltage detector 13
When the diamond voltage of f and the output voltage V'M of the voltage detector 12 becomes smaller than a certain voltage value ΔVo, an output voltage V^ is obtained via the first-order lag element 18.

In the comparison amplifier 16 of the current control section 15, the input terminal 2
The voltage V'IP passed through the first-order delay element 19 to the current command values V, P from the voltage detector 11 is compared with the voltages V, M from the voltage detector 11 and the output voltage V^ from the voltage controller 14. , give the deviation to the phase shifter 21 via the first-order delay element 20,
The output of the phase shifter 21 is used to adjust the conduction rate of the chopper 9 to control the motor current. By the way, the resistor 7 is inserted in a high-speed operation where the motor voltage EM is higher than the equivalent power supply voltage Vd (11ym), and when the resistor 7 is inserted, the voltage control section 14 is such that the voltage VM is Vc.
It acts so that it does not become higher than f(1-ym).

The motor decelerates and the motor voltage EM changes to the equivalent power supply voltage Vd (
1-ym), the resistor 7 is short-circuited by the short-circuit contactor 8. That is, the contactor 8 may be turned on when the condition of the following '1' formula is satisfied. VMmiVCf(1-
ym)-IMR .

That is, since the power supply voltage EM in the above publication is equivalent to the power supply voltage Vd of the filter capacitor 3, if 8M is multiplied by Vd for both Vcf and layer change and transferred, the above {1
One formula is obtained. That is, as stated in the above publication,
This means that the resistor short-circuit is performed under the condition that the conductivity of the chopper after the resistor short-circuit becomes approximately the minimum value.

However, since both motor current IM and voltage EM are small when regenerative braking is started, equation '1} is satisfied at the same time as regenerative braking is started.

Therefore, as shown in Fig. 3, the contactor 8 can be turned on after the time t has elapsed from the start of regenerative braking until the current commands V' and P rise, and when formula m is satisfied. , as shown in FIG.
The AND circuit 33 calculates the AND of the outputs of the two, and the output activates the control circuit 34 to issue a command to close the contactor 8. However, with such conventional devices, there is no problem if the electric motor speed at the start of regenerative braking is high, but if the speed is low, the time control and later the resistance 7
Since the motor current IM rises after IM is short-circuited, there is a drawback that the control effect is delayed. for that,
So-called spotting is being considered, in which the motor speed is detected and the resistor 7 is short-circuited in advance if the speed is low, but in this case, a speedometer is required, and the When there are many, there is a disadvantage that the number becomes large and expensive.

The present invention provides means for detecting the maximum conduction rate of the chopper in addition to means for detecting that a predetermined period of time has elapsed since the start of braking, and allows short-circuiting of the resistors by the logical sum of the outputs of these means. An object of the present invention is to provide a motor control device that can quickly start up a current with a simple circuit configuration.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 4 shows an embodiment of the motor control device according to the present invention, in which 35 is a chopper maximum conduction rate detection circuit, 36
is an OR circuit.

Other symbols correspond to the same symbols in FIG. In such a configuration, the OR circuit 36 calculates the logical sum of the signal from the timer 32 indicating that the time has elapsed and the signal indicating that the chopper conduction rate has reached the maximum from the detection circuit 35.
The AND circuit 33 performs a logical product of the output and a signal from the detection circuit 31 indicating that the condition of equation (1) is satisfied, and based on the output, a contactor closing command is issued from the control circuit 34. issue.

At the start of regenerative braking, if the motor speed is high, the motor current will rise before the chopper's current flow rate reaches its maximum, but if the motor speed is low, the chopper will reach its maximum current flow rate. Therefore, providing conditions that allow the short-circuit contactor 8 to be turned on as described above is very effective in raising the current when the motor speed is low.

In other words, from the viewpoint of the ride comfort of electric cars, it is about 1~
It is set to 2 seconds, but the time it takes for the chopper's conduction rate to reach its maximum is 0.1 to 0.2 seconds, so it is very useful for quickly ramping up the current at low speeds. This will have a large effect. Note that in order to detect the maximum conduction rate of the chopper with the detection circuit 35, for example, the phase shifter 21
The input voltage and the on/off signal interval of the chopper may be used, and the detection may be performed on the condition that the maximum conduction rate detected in this way continues for a certain period of time.

FIG. 5 shows another embodiment of the motor control device according to the present invention, in which 37 is a detection circuit for detecting that the motor voltage is below a predetermined value, and 38 is an AND circuit.

The other configurations are the same as in FIG. 4. In this example, the AND circuit 38 performs the logical product of the signal from the detection circuit 35 indicating that the chopper has reached the maximum conduction rate and the signal from the detection circuit 37 indicating that the motor voltage is below a predetermined value. bird,
The OR circuit 36 takes the logical sum of this AND output and the signal from the timer 32, and the AND circuit 33 takes the AND of this logical sum output and the signal from the detection circuit 31, and the output is used to connect the contactor. 8 inputs are made. The example shown in FIG. 5 is suitable for performing regenerative brake control by bringing the motor field 5 into a weak field state using a resistance shunt.

When the motor field 5 is resistively shunted, the field current is controlled with a delay with respect to changes in the electric motor flow, so that the rise of the motor current at the start of regenerative braking is delayed. This means that
Even in the high speed range of the motor, a speed castle occurs where the current flow rate of the chopper 9 reaches its maximum when regenerative braking is started, and in the embodiment shown in FIG. becomes impossible. Therefore, in this embodiment, the current flow rate of the chopper is determined by taking the logical product of the chopper's maximum conduction rate detection signal and the signal indicating that the motor voltage has reached a predetermined value. Even if the voltage reaches the maximum value, if the motor voltage at that time is equal to or higher than a predetermined value, the resistor 7 will not be short-circuited. Since there is a clear difference in the motor voltage when the chopper 9 reaches the maximum conduction rate when the motor speed is high and low, the above predetermined value can be easily set. Since the current conductivity of the chopper 9 is maximized and the motor voltage is below a predetermined value, the resistor 7 can be quickly short-circuited. As described above, according to the present invention,
Furthermore, even when the motor speed is low, the current can be quickly ramped up at the start of regenerative braking.

[Brief explanation of drawings]

FIG. 1 is an overall structural diagram of a motor control device to which the present invention is applied, FIGS.
5 and 5 each show a configuration diagram of an embodiment of the resistance control circuit portion of the motor control device according to the present invention. Explanation of symbols, 5... Electric Motor Kaiji, 6...
・Motor armature, 7...Resistance, 8...
Short-circuit contactor, 9... Chotupa, 31, 35...
...Detection circuit, 32...Timer, 33...
AND circuit, 34... Control circuit, 36...
...OR circuit. Figure 2 Tsutomu Figure 3 Tsutomu' Figure 4

Claims (1)

[Scope of Claims] 1. A chopper in which a resistive element connected in parallel with a short-circuiting means is inserted in series with an electric motor to control the current flowing through the motor to perform regenerative braking control, and a chopper after the resistive element is short-circuited A resistor short-circuiting control system that turns on the short-circuiting means under conditions where the conduction rate is approximately minimum, the first means for detecting that a predetermined time has elapsed since the start of regenerative braking, and the chopper controlling the short-circuiting means to the maximum conduction rate. a second means for detecting that the resistance has become low, and a limiting means for permitting the resistor short circuit control system to turn on the short circuit means only when a logical sum output of the detection outputs of the first and second means is generated. An electric motor control device characterized in that: 2. A chopper that controls the regenerative brake by controlling the current flowing through the motor by inserting a resistive element connected in parallel with a short-circuiting means in series with the electric motor, and a chopper whose current conductivity after the resistive element is short-circuited is almost the minimum. A resistor short-circuiting control system that turns on the short-circuiting means under conditions such that: a first means for detecting that a predetermined time has elapsed from the start of regenerative braking; and a first means for detecting that the chopper has reached a maximum conduction rate; a second means for detecting that the motor voltage is within a predetermined range; and a third means for detecting that the motor voltage is within a predetermined range; An electric motor control device characterized in that it is provided with a limiting means for performing a logical sum with the detection output of the means and for permitting the resistor shorting control system to turn on the shorting means only when the logical sum output is generated.