JPS6137842B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chopper control device for an electric vehicle, and particularly relates to an improvement in a short-circuit control method for a resistor in a chopper in which a resistor is inserted in series with the motor to expand the regenerative area during regenerative braking. be.

Figure 1 shows the main circuit diagram of a typical electric vehicle, Chotsupa, during regenerative braking. In the figure, 1 is the power supply line,
2 is an integrated device such as a pantograph; 3 is a filter reactor; 4 is a filter capacitor; 5 is a freewheel diode; 6 is a chopper that conducts and interrupts the main circuit current and controls the conduction period to control the motor current; 7 is a main smoothing reactor for smoothing the motor current, and 8 and 9 are the motor field and armature.

In the regenerative brake main circuit as shown in Fig. 1, if the internal resistance of the main circuit is ignored, the so-called motor voltage E _M between the positive side of the armature 9 and the ground point is
must be controlled to be lower than the voltage E _c of the filter capacitor 4. If this is not done, the motor current I _M that increases when the chopper 6 is turned on will not decrease but increase even when the chopper 6 is turned off. This is because the motor current I _M and the motor voltage E _M diverge due to a so-called self-excitation phenomenon.

That is, if the conduction rate of the chopper 6 is γ, the following relational expression holds true between the motor voltage E _M and the voltage E _c of the filter capacitor 4.

E _M = (1 - γ) E _c ...... (1) If the minimum conduction rate of the chopper 6 is γ _nio , then for a certain filter capacitor voltage _c , E _{M nax} = (1 - γ _nio ) The maximum value E _{M nax} of the voltage E _M expressed by E _c (2) is determined.

Therefore, the motor voltage E _M must be controlled so as not to exceed this maximum value E _{M nax} . Specifically, by narrowing down the motor current I _M from the required value, the motor's electromotive force is suppressed, and the maximum voltage E _M
It is controlled so that it does not exceed _nax . Note that this control is generally called a motor voltage limiter.

The function of this motor voltage limiter will be specifically explained with reference to FIG. In Fig. 2, the horizontal axis shows the motor current I _M , and the vertical axis shows the speed V of the train (which can be thought of as the motor rotation speed).
V ₁ represents the maximum braking initial speed, and I _M1 represents the maximum braking current. Here the curve _K1 is
It represents the relationship between speed V and motor current I _M such that motor voltage E _M satisfies equation (2) when filter capacitor voltage E _c is a certain constant value and conduction rate is γ _nio . In other words, it can be considered as a curve in which the motor voltage E _M is a constant value E _{M nax} .

If the maximum brake is applied at speed V ₁ , it is necessary to flow a motor current of I _M1 in order to obtain the necessary braking force, but at speed V ₁ the motor current I _M is at the point I _M1 , that is, point A. is above the curve K ₁ , so E _M >(1−γ _nio ) E _c (3) and the motor current I _M and motor voltage E _M diverge. Therefore, it can be seen that the shaded area is an uncontrollable area.

Therefore, the motor current I _M is limited to I _M2 by the aforementioned motor voltage limiter. Thereafter, as the speed V decreases, the motor voltage E _M is controlled to be constant along the curve _K1 , and when the speed V reaches _V2 , constant current control is performed at the required brake current I _M1 .
In the speed range from V ₁ to V ₂ , the electric braking force generated by the regenerative braking is insufficient from the required braking force by the amount indicated by the diagonal lines in the figure, so this amount is supplemented by the air brake. Therefore, the full regeneration initial speed in this case is _V2 .

By the way, in order to expand the regenerative braking area, increase the full regenerative initial speed, lighten the load on the air brake, reduce wear on the brake shoe, and increase regenerative power, there has been a conventional method as shown in Figure 3. It has been implemented. In addition, in Figure 3, the first
Components that are the same as those in the figures are designated by the same reference numerals. 10 is a regeneration area expansion resistor inserted in series with the motor field 8 and the electromagnetic element 9 to expand the regeneration area;
1 is a switch for short-circuiting the resistor 10. Assuming that the resistance value of the resistor 10 is R, a voltage drop of I _M ·R occurs due to this resistor 10, and the motor voltage E _M appears to drop by I _M ·R. Therefore, the electromotive force of the motor can be controlled substantially higher by that amount.

Figure 4 shows the characteristics in this case. In FIG. 4, the curve _K1 is the same as _the curve _K1 shown in FIG. 11 is open and the resistor 10 is inserted. In this way, series resistance 10
As a result, the regeneration area is expanded, the supplementary amount by the air brake (the shaded area in the figure) is reduced, and the full regeneration initial speed is increased to _V'2 .

When the maximum brake is applied from the speed _V1 , the motor current I _M is throttled down to I _M2 ' (point D in FIG. 4), but this is a smaller amount than when the resistor 10 is not provided. Thereafter, the motor voltage E _M is constant voltage controlled by E _{M nax} along the curve K ₂ up to point C, and C
From this point, constant current control is performed with the required current I _M1 .

However, if the resistor 10 remains inserted, I _M ²・R always remains at point B, that is, in the region below the speed V ₂
There is a power loss, the regenerated power is reduced, and the capacity of the resistor 10 is increased, which is uneconomical. In the low speed range, on the other hand, the lower limit speed of constant current control increases due to the voltage drop caused by the series resistance, making it impossible to perform effective regeneration control. Therefore, resistor 1
0 is desirably short-circuited by the switch 11 at point B (the intersection of the straight line with constant I _M =I _M1 and the curve K ₁ ).

However, point B is a short circuit point when the brake current I _M is maximum I _M1 , and as the brake current changes depending on the brake command from the driver's cab and the load conditions, the point at which the short circuit should be made also changes. For example, in FIG. 4, when the brake current is I _M3 , the short circuit point is point B'. Therefore, in order to detect the short circuit point, motor voltage E _M , filter capacitor voltage E _c , motor current I
The following method of calculating _M is used.

That is, when the motor current is a certain value I _M (which varies depending on the brake command and load conditions as described above), the motor voltage E _M after shorting the resistor 10 is
(Let this be E _M ′) as long as it satisfies E _M ′ < (1−γ _nio ) E _c (4).

Now, the motor voltage E _M is the voltage between the ground point and the positive point of armature 9, so resistor 10
The motor voltage E _M when short-circuiting increases by I _M · R compared to the motor voltage E _M before short-circuiting, so E _M '=E _M +I _M R<(1-γ _nio ) E _c ...... It is sufficient to satisfy (5). Therefore, the motor voltage E _M , the motor current I _M , and the filter capacitor voltage E _c are calculated, and the point that satisfies the condition of equation (5) is set as a resistance short-circuit point, and the resistor 10 is short-circuited by the switch 11 .

By the way, after detecting the condition of equation (5), simply switch 1.
If only 1 is turned on, the motor voltage E _M will jump up by I _M · R in steps, so the chopper 6
The transient throttling due to the filter capacitor voltage E _c also jumps because the motor current I _M jumps up. If this jump amount is large, an overcurrent detection circuit for the motor current I _M or an overvoltage detection circuit for the filter capacitor voltage will operate, causing a problem that the main circuit will be cut off.
Further, if a surge occurs in the motor current I _M , the braking force changes rapidly, which impairs riding comfort.

Therefore, as a conventional method for solving this problem, a method as shown in FIG. 5 has been implemented, in which parts corresponding to those in FIG. 3 are denoted by the same reference numerals. 12 is a voltage detection device for detecting the voltage E _c of the filter capacitor 14; 13 is a voltage detection device for detecting the voltage E _M between the positive side point of the armature 9 and ground; 14
15 is a _solenoid valve or operating coil for turning on switch 11; 16 is a brake command device located in the driver's cab; The speed is sent to brake current pattern generation circuit 18. The brake current pattern generation circuit 18 receives the deceleration command from the brake command device 16 and the signal from the load detection device 17, and calculates and generates a necessary brake current pattern. 19
is the aforementioned motor voltage limiter that compares the output E _c from the filter capacitor voltage detection device 12 and the output E _M from the motor voltage detection device 13 to prevent the motor voltage E _M from exceeding the filter capacitor voltage E _c . , serves to narrow down the motor current I _M .

On the other hand, 20 is an overhead wire voltage limiter which operates as follows.

In other words, during regenerative braking, the _current Is regenerated to the load such as another power vehicle through the power supply line 1,
The following relational expression holds between the motor current I _M and the conduction rate γ.

I _s = (1-γ) I _M ………(6) If there is sufficient regenerative load, the motor current I
_M is constant current controlled at a required value (provided that the motor current I _M is not limited by the motor voltage limiter 19 mentioned above), and the current I _s expressed by equation (6) is regenerated. However, if there is not enough regenerative load to flow the regenerative current I _s expressed by equation (6), the regenerative current that has no place to go will be accumulated in the filter capacitor 4, and the filter capacitor voltage E _c and the voltage of the feeder line 1 will increase, so the voltage of the feeder line 1 will be kept constant by reducing the motor current I _M from the required value to a current that can absorb the regenerative current I _s into the regenerative load. control to maintain Overhead line voltage limiter 2
0 performs this operation in response to the filter capacitor voltage E _c from the voltage detection device 12. The reference numeral 24 simply represents the central part of the control of the chipper 6, and is called a comparison calculation part. When the motor voltage limiter 19, the overhead wire voltage limiter 20, and the narrowing down circuit 23 (described later) are not working, the comparison calculation unit 24 compares the brake current pattern which is the output from the brake current pattern generation circuit 18 with the brake current pattern output from the brake current pattern generation circuit 18, and
The motor current I _M as a feedback amount output from the current detection device 14 is compared, and the conduction rate of the chopper 6 is calculated so that the motor current I _M becomes equal to the brake current pattern.

Furthermore, 25 is a gate pulse generation circuit, which is a circuit that generates a so-called gate pulse for turning on and off the chopper 6. Normally, the conduction rate of the chopper 6 is changed by generating on-pulses at regular intervals and changing the phase of the off-pulses according to the output from the comparison calculation section 24.

On the other hand, 21 is a circuit for detecting the conditions for short-circuiting the resistor 10, which includes the filter capacitor voltage E _c from the voltage detection device 12, the motor voltage E _M from the voltage detection device 13, and the current detection device 14. The condition of the above equation (5) is detected with the motor voltage I _M from .

Further, 22 is a circuit that receives the output of the resistor short circuit condition detection circuit 21 and excites the operating coil or solenoid valve 15. Furthermore, 23 is a current narrowing circuit,
This circuit receives the output of the resistor short circuit condition detection circuit 21 and temporarily narrows down the motor current I _M .

The operation when the motor voltage limiter 19 and the overhead line voltage limiter 20 are working will be described below.

The output of the brake current pattern generation circuit 18 is
_p , the output of the motor voltage limiter 19 I _MLM , the output I _sLM of the overhead line voltage limiter 20, the current detection device 1
The output I _M from 4 and the output of the current narrowing circuit 23 are assumed to be I _sH . Here, the polarity of each signal is positive for the signal I _p , and for the other signals I _M , I _MLM , I _sL
M and _IsH are negative.

The comparison calculation unit 24 controls the conduction rate of the chopper 6 so that the deviation between the positive and negative signals at the input becomes zero. Therefore, when I _MLM =I _sLM =I _sH =0, the motor current I _M is controlled so that I _p =I _M (7). Therefore, the motor current I _M of the main circuit is controlled at a value corresponding to the output from the brake current pattern generation circuit 18. However, motor voltage limiter 1
9. When the overhead line voltage limiter 20 is working, I _MLM ≠ 0 and I _sLM ≠ 0, so the motor current I _M is controlled so that I _p = I _M + I _MLM + I _sLM (8) .

That is, I _M = I _p - (I _MLM + I _sLM ) (9), and the motor current I _M is determined by the pattern voltage I _p , the output I _MLM of the motor voltage limiter 19, and the output I of the overhead line voltage limiter 20. It will be controlled by the value subtracted by the output of _sLM .

The current narrowing circuit 23 also has a similar function, and I _sH
In the case of ≠0, I _M = I _p −I _sH (10), and the motor current I _M is
will be narrowed down by the output _IsH .

By the way, since the output I _p from _the brake current pattern generation circuit 18 is input to the current narrowing circuit 23 as shown in FIG. It's summery. This is because the brake current pattern changes over a wide range depending on the output from the brake command device 16 and the output from the load detection device 17, so the amount of narrowing down is made in accordance with this brake current pattern. If the amount of throttling is constant without doing this, if the brake current is large, the amount of throttling will be insufficient when the resistor 10 is short-circuited, so when the motor current I _M and the filter capacitor voltage E _c jump, the amount of throttling will be insufficient. However, the above-mentioned problem will occur, and if the throttle amount is set to suppress the amount of jump at the maximum brake current, conversely if the brake current is small, the throttle amount will be too large and the main circuit will This is because if the inserted current detection relay (not shown) falls and the main circuit turns off, problems such as irritation may occur.

The conventional control method described above with respect to FIG.
There were two drawbacks described below.

The first drawback is that the throttling amount _IsH , which is the output from the current throttling circuit 23, is proportional to the brake current pattern _Ip , so when the above-mentioned overhead line voltage limiter 20 is working, I _M = I _p - I _sLM ......(11) Since the motor current I _M is reduced by I _sLM , when the regenerative load is small and I _sLM is large, the amount of reduction becomes excessive and the motor When the current is narrowed down, the current detection relay falls and the main circuit turns off, causing a problem. In Chiyotsupa vehicles, once the current relay falls during braking and the main circuit is turned off, the brake circuit cannot be re-established, and the air brake acts to bear the entire braking force until the brake is turned off. Therefore, in this way, the circuit is turned off during braking,
After that, all the burden is on the air brake, which means that the resistor 10 is inserted to reduce the burden on the air brake and reduce wear on the brake shoe, as well as increase regenerative power and make the vehicle more economical. It ends up going against the ultimate purpose.

A second drawback of the conventional system shown in FIG. 5 is that the current narrowing circuit 23 operates in synchronization with the output of the resistor short circuit condition detection circuit 21. That is, the operating coil or solenoid valve 15 is also excited through the excitation circuit 22 in synchronization with the output of the resistance short condition detection circuit 21, but the operating coil or solenoid valve 15 is not energized until the contact of the switch 11 is actually turned on. Since there is a delay in the operation after the filter capacitor voltage is applied, the timing of the narrowing down is inappropriate, and the motor current I _M is not sufficiently narrowed down, resulting in a jump still occurring in the motor current I _M and the filter capacitor voltage E _c . .

That is, the waveforms of the signals of each part and the motor current I _M are as shown in the timing chart of FIG. FIG. 6a shows the output of the resistance short circuit condition detection circuit 21. In synchronization with this, the excitation circuit 22 is turned on as shown in FIG. 6b, and the current narrowing circuit 23 is turned on.
Then, a narrowing down command I _sH as shown in FIG. 6 d is issued, and the motor current I _M is narrowed down as shown in FIG. 6 e. However, as shown in Figure 6c, switch 1
Since contact 1 has an operation delay of time T ₁ ,
Contact 11 is actually turned on and the motor current I _M is ΔI ₂
When it jumps up, the narrowing amount I _sH is already
is about to return from the most narrowed state, and a jump occurs in the motor current I _M with respect to the pattern current I _p as shown by ΔI ₃ .

The present invention has been made to solve the above problems, and is capable of expanding the regeneration area, reducing the burden on the air brake, reducing wear on the brake shoe, and improving regenerative current. The purpose is to obtain a control device.

The electric vehicle chopper control device according to the present invention detects the filter capacitor voltage with a voltage detection device,
The voltage of the series circuit of the motor and the regenerative area expansion resistor is detected by a voltage detection device, the motor current is detected by a current detection device, and the short-circuit condition of the resistor is determined based on the outputs from the three detection devices. is detected by the resistance short circuit condition detection device, and after a predetermined time limit has elapsed based on the output signal from the resistance short circuit condition detection device, the time limit is approximated to be smaller than the operation delay time of the short circuit switch. A timer circuit is operated, and in synchronization with the output signal output by the operation of this timer circuit, a current narrowing circuit sends out a signal proportional to the output of the current detection device, and the output of this current narrowing circuit is The total value of the output of the current detection device and the brake current pattern are compared to calculate the conduction rate of the chopper by a comparison calculation device, and the motor current is narrowed down based on the calculation result.

Hereinafter, an example of the present invention will be described in detail with reference to FIG. 7, in which parts corresponding to those in FIG. 5 are denoted by the same reference numerals.

In FIG. 7, 26 is a timer circuit which operates in synchronization with the output from the resistor short circuit condition detection circuit 21 and outputs an output only after time _T2 . This time T ₂ is approximately the same as the operation delay time T ₁ of the switch 11 described above, and is set in advance so that T ₂ <T ₁ .

On the other hand, the output I _M from the current detection device 14 is input to the current narrowing circuit 23, and the conventional embodiment shown in FIG.
In contrast to outputting the narrowing down amount I _sH proportional to the brake current pattern I _p from 8, the narrowing down amount I _sH proportional to the brake current I _M is output.

In the above configuration, even if the overhead line voltage limiter 20 is operating and the motor current is narrowed down from the brake current pattern I _p as expressed by I _M = I _p - I _sLM (12), the resistor 10 The amount of current throttling when short-circuiting is proportional to the current I _M actually flowing through the motor, so problems such as the current relay falling due to the throttling amount being too large will not occur.

Moreover, when the overhead line voltage limiter 20 is not operating, I _M = I _p (13), so the command from the brake command device 16 and the command from the load detection device 17 in the conventional embodiment are There is no difference in the function of narrowing down according to the brake current pattern I _p that changes according to the output.

Further, by providing the timer 26, the timing of current throttling becomes appropriate, and the jump in motor current I _M can be suppressed. To explain this with reference to Fig. 8, Fig. 8 a, b,
Symbols c are the same as those in FIGS. 6a, b, and c, and respectively indicate the output of the resistance short-circuit condition detection circuit 21, the operation coil, or the state of the contact of the output switch 11 of the excitation circuit 15 of the solenoid valve.

On the other hand, FIG. 8d shows the output of the timer 26, which outputs the time _T2 after receiving the output of the resistor short-circuit condition detection circuit 21. FIG. 8e shows the output _IsH of the current narrowing circuit 23, and the timer 26
output in synchronization with the output of In this way, since the output of the current narrowing circuit 23 is output after a time T ₂ after the excitation circuit 22 is turned on, the motor current I _M changes to ΔI ₂ immediately after the narrowing down is the most, as shown in FIG. 8f. The amount of jump of motor current I _M with respect to I _p is ΔI ₃ ', which is equal to ΔI ₃ of the conventional method described above with respect to FIG. 6e.
will be much smaller than. At the same time, the period during which the current is narrowed is T ₁ in the conventional case, but according to the present invention, it is shortened to T ₁ - _{T 2} ≒ 0,
Riding comfort will no longer be impaired due to sudden changes in brake torque due to current throttling.

As described above, according to the present invention, a resistor is inserted in series with the motor in order to expand the regenerative area, reduce the burden on the air brake, reduce wear on the brake shoe, and improve regenerative power. When short-circuiting the resistor, the optimum narrowing is performed at the optimum timing, which prevents the main circuit from turning off due to excessive narrowing at light loads, which was a drawback of the conventional method. Riding comfort can be further improved by suppressing surges in motor current and filter capacitor voltage.

[Brief explanation of the drawing]

Figure 1 is a connection diagram showing a typical chopper regeneration main circuit to which the present invention can be applied, Figure 2 is a characteristic curve diagram showing its operating characteristics, and Figures 3 and 4 are conventional circuits that are improved from Figure 1. 5 is a systematic connection diagram showing a conventional regenerative brake control device, and FIGS.
FIG. 7 is a systematic connection diagram showing an example of the electric vehicle chopper control device according to the present invention, and FIGS. 8 a to 8 f are timing charts for explaining the operation. 1: Power supply line, 3: Filter reactor, 4: Filter capacitor, 6: Chopper, 8, 9: Motor field, armature, 10: Resistor for expanding regeneration area, 11: Short circuit switch, 12: Filter capacitor , 13: Voltage detection device, 14: Motor current detection device, 16: Brake command device, 17: Load detector, 18: Brake current pattern generation circuit, 1
9: Motor voltage limiter, 20: Overhead line voltage limiter, 21: Resistor short circuit condition detection circuit, 22: Excitation circuit, 23: Current narrowing circuit, 24: Comparison calculation section, 25: Gate pulse generation circuit, 26: Timer circuit.

Claims (1)

[Claims] 1. In a regenerative brake control device for an electric vehicle using a chopper, which has a regenerative area expansion resistor connected in series with the motor and a short-circuit switch installed in parallel with this resistor, a voltage detection device that detects the filter capacitor voltage and a motor a voltage detection device that detects the voltage of the series circuit of the resistor; a current detection device that detects the motor current; and a resistor short-circuit condition that detects the short-circuit condition of the resistor based on the outputs from the three detection devices. a detection device; an excitation circuit that operates the short circuit switch according to the output of the resistance short circuit condition detection device; and an excitation circuit that operates the short circuit switch after a predetermined time has elapsed based on the output signal from the resistance short circuit condition detection device. and a timer circuit that sets the time limit to a value smaller than the operation delay time of the short circuit switch, and a current throttle that sends out a signal proportional to the output of the current detection device in synchronization with the output signal of the timer circuit. circuit, and a comparison calculation device that calculates the current flow rate of the chopper by comparing the total value of the output of the current narrowing circuit and the output of the current detection device with the motor current pattern. An electric vehicle chopper control device, characterized in that it suppresses jumps in motor current and filter capacitor voltage by narrowing down the current based on the output of the comparison calculation device.