JPS6181183A - Chopper controller - Google Patents

Abstract

PURPOSE:To suitably switch between a generating brake control and a regenerative brake control by applying an ON pulse to a brake thyristor synchronously with an OFF pulse to a chopper during the simultaneous operation of the regenerative brake control and the generating brake control. CONSTITUTION:A pantograph 1 of an electric railcar and a chopper controller are connected by a circuit having unit switches 2, 4, a high speed breaker 3, a charging resistor 5 and a filter reactor 6, and a chopper controller has a brake circuit 30 and a chopper circuit 40. An ON pulse is applied to the brake thyristor 8 of the brake circuit 30 synchronously with an OFF pulse from a chopper ON pulse generator 23 to the circuit 40 during the simultaneous operation of the regenerative brake control by the circuit 40 and the generating brake control by the circuit 30. Thus, if the thyristor 8 is turned ON when the chopper is OFF, an improper forward voltage is not generated at the thyristor 8, and the generating brake control and the regenerative brake control can be smoothly switched.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a chopper control device that uses both a regenerative brake control function and a power generation brake control function.

[Technical Background of the Invention and Problems Therein] There are various braking systems for electric motors such as series-wound motors, such as dynamic braking and regenerative braking. Figures 4 and 5 of the attached drawings are shown below.
The prior art will be explained with reference to the drawings. In addition, in the following description of the drawings, the same elements are indicated by the same reference numerals.

FIG. 4 is a configuration diagram of an example of a conventional device used in a train. The pantograph 1 of the train and the chopper control device are connected by a circuit consisting of a unit switch 2, a high speed circuit breaker 3, a unit switch 4, a charging resistor 5 and a filter reactor 6. The chopper control device connects a brake circuit 30 consisting of a brake thyristor 8J5 and a brake resistor 9 connected in series, a series connection of a main thyristor 11 and a commutation reactor 12, and a series connection of an auxiliary thyristor 13 and a commutation capacitor 14 in parallel. It has a chopper circuit 40 connected thereto. And brake circuit 3
0 and the chopper circuit 40 are freewheeling diodes 1
They are connected in parallel via 0. Further, a field coil 16 and an armature coil 17 are connected to these circuits through parallel connections of a main smoothing reactor 15, a unit switch 18, a high speed circuit breaker 19, and a current reducing resistor 20.

In the above circuit, the voltage across the brake circuit 30 is detected by the voltage detector 21 provided in parallel with the filter capacitor 7, and the current flowing through the electric akebono coil 17 is detected by the current detector 22.

The brake thyristor on pulse generation circuit (hereinafter referred to as "brake on circuit") 24 generates a brake thyristor on pulse based on the output of the voltage detector 21, and the on pulse amplifier 24A amplifies this and applies it to the gate of the brake thyristor 8. . In addition, a chopper on-off pulse generation circuit (hereinafter referred to as "chopper on-off circuit") 23
generates a chopper-on pulse and a chopper-off pulse based on the output of the voltage detector 21 and the output of the current detector 22. The on-pulse width amplifier 23A and the off-pulse amplifier 23B amplify these signals and provide them to the gates of the main thyristor 11 and the auxiliary thyristor 13.

It is well known that in the apparatus shown in FIG. 4, regenerative brake control is performed by turning on and off the chopper circuit 40. It is also well known that when performing dynamic braking control, the brake thyristor 8 is fired to supply current to the brake resistor 9, which is a load, to control the chopper on and off. The operation of the configuration example shown in FIG. 4 will be described below with reference to the waveform diagram in FIG.

When the output 28 of the voltage detector 21 is below a certain set value,
Regenerative brake control is performed by turning the chopper on and off. That is, at time t1, chopper on pulse 2
When 5 is output, the main thyristor 11 is fired and power can be recovered. As a result, the value of the output 28 of the voltage detector 21 decreases.

When the chopper-off pulse 26 is output at time t2, the auxiliary thyristor 13 is turned on, and the main thyristor 11 is turned off by the commutation operation.

Regenerative brake control is executed by turning on and off the chopper as described above, but when the regenerative load decreases, the terminal voltage of the filter capacitor 7 increases, and eventually exceeds a certain set point at the output 28 of the voltage detector. It becomes like this.

That is, when the output 28 exceeds the set value VA at time t3, the brake-on circuit 24 outputs the on-pulse 27 and the brake thyristor 8 is fired. In this way, the regenerative brake control is switched to the dynamic brake control, energy is consumed by heat radiation from the brake resistor 9, and the voltage between both terminals of the filter capacitor 7 is lowered.

At time t4, the chopper on pulse 25 is generated again, and at time t5, the chopper off pulse 26 is generated to execute chopper on/off control, but it should be noted here that the brake thyristor on pulse 27 will continue to occur after that. This is because even if the regenerative load increases and regenerative brake control becomes possible after switching to dynamic brake control, the conventional device does not have a function to extinguish the brake thyristor 8, so the brake is turned off and the unit switch 2 This is because the brake thyristor 8 does not extinguish until the current flowing through the brake thyristor 8 becomes equal to or less than the holding current when the brake thyristor 18 is opened. Therefore, once regenerative brake control is switched to power generation brake control, operation using only regenerative brake control is no longer possible.

As described above, the conventional device has the disadvantage that electric power is wasted because it is not possible to appropriately switch between regenerative brake control and dynamic brake control according to the voltage between the terminals of filter capacitor 7.

Therefore, as will be explained in detail later with reference to FIGS. 1 and 2, by connecting the chopper circuit 40 in parallel with the brake circuit 30, the main thyristor 11
A method has been proposed in which the arc of the brake thyristor 8 is extinguished by extinguishing the arc of the brake thyristor 8, and the electric power generation brake control is switched to the regenerative brake control. However, in this method, when the brake thyristor 8 is turned off when the chopper is turned off, an incorrect voltage in the forward direction is generated, and the brake thyristor 8 may be damaged by voltage.

[Purpose of the invention]

The present invention has been made to overcome the drawbacks of the above-mentioned prior art, and appropriately switches between dynamic brake control and regenerative brake control without generating an incorrect voltage when extinguishing the brake thyristor when the chopper is turned off. An object of the present invention is to provide a chopper control device that can perform the following operations.

(Summary of the Invention) In order to achieve the above object, the present invention provides a chopper control device which provides an on-pulse to a brake thyristor in synchronization with an off-pulse to the chopper circuit during combined operation of regenerative brake control and electric generation brake control. It provides:

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a chopper control device according to the same embodiment. The difference from the configuration example in FIG. 4 is that the brake circuit 30
and the chopper circuit 40 is a free-wheeling diode 10
The functions of the brake thyristor on pulse generation circuit (brake on circuit) 29 are different from the function of the brake on circuit 24, and chopper on and off signals are given to it. It is that you are. Here, it is conventionally known that commutation operation can be made possible by connecting the brake circuit 30 and the chopper circuit 40 in parallel without using the freewheeling diode 10 as shown in FIG. It is also known to switch to the electric power braking control by extinguishing the main thyristor 11 and then extinguishing the brake thyristor 8.

However, the present invention is completely different from the prior art in how the brake thyristor on pulse 27 is applied (in other words, the function of the brake on circuit 29). This will be explained in detail below with reference to the waveform diagrams of FIGS. 2 and 3.

FIG. 2 shows the operation of the device of FIG. 1 according to a conventional method. As explained with reference to FIG. 5, when the voltage of the filter capacitor 7 exceeds a certain set value at point t1, the chopper-on pulse 25 is output, the main thyristor 11 is fired, and the main thyristor current increases. do. Next, when the chopper-off pulse 26 is output at time t2, the auxiliary thyristor 13 is fired, and a reverse current is applied during the period T1 by the commutation operation, and the main thyristor 11
The arc is extinguished.

When the regenerative load decreases and the voltage of the filter capacitor 7 rises and exceeds a certain set value vA at time t3,
The brake thyristor on pulse 27 is output and the brake thyristor 8 is fired. Therefore, the current of the brake thyristor 8 increases and power generation brake control is performed.

Here, when the chopper-on pulse 25 is output at time t4, the main thyristor 11 is fired, and the main thyristor 1
The current through brake thyristor 8 increases sharply, whereas the current through brake thyristor 8 decreases rapidly. As a result, the power generation brake control is switched to the regenerative brake control.

Next, when the chopper-off pulse 26 is output at time t5, the auxiliary thyristor 13 is fired, the commutation operation causes the main thyristor 11 to be extinguished in a period T1, and the brake thyristor 8 is extinguished by a reverse voltage in a period T2. .

As mentioned above, when the device shown in FIG. 1 is operated as shown in the waveform diagram of FIG. 2, the problem is that a forward voltage is applied to the brake thyristor 8 during the period T3. This forward voltage is generated when the discharge current of the commutating capacitor 14 flows into the commutating reactor 12, and when L is the inductance of the commutating reactor 12, the forward voltage V becomes V = L - di/dt.

The fact that a forward voltage is generated in the brake thyristor 8 during the period T3 indicates that no forward current flows through the brake thyristor 8, or in other words, that the brake thyristor 8 has been extinguished before that time. The brake thyristor 8 is turned off at time t4 when the main thyristor 1
This is thought to have occurred because when the brake thyristor 1 was ignited, the current in the brake thyristor 8 was transferred to the main thyristor 11 as shown in FIG. 2, and the current passing through the brake thyristor 8 became less than the holding current. However, the brake thyristor on pulse 27 may be output directly from the chopper off pulse 26, and because the period from time t1 to t5 is short, the brake thyristor current may not become equal to or less than the holding current.

In the above case, especially the brake thyristor 8
For example, if the brake thyristor 8 is composed of a plurality of thyristor elements connected in series,
If a forward voltage (incorrect voltage) is applied during period T3 when only one of the thyristor elements is extinguished, a voltage higher than the withstand voltage will be applied to the extinguished thyristor element and it will be destroyed. There is.

Therefore, in the present invention, by generating a brake thyristor on-pulse 27 as shown in FIG. 3, the possibility of an incorrect voltage being applied to the brake rust 3 or 8 during extinguishing is eliminated. Referring to FIGS. 1 and 3, the brake-on circuit 29 is supplied with the output 28 of the voltage detector 21 and the chopper-on pulse 25 and chopper-off pulse 26 from the chopper on-off circuit 23. Therefore, the brake-on circuit 29 is activated in synchronization with the chopper-off pulse 26 (time t5 in FIGS. 2 and 3).
) Generates a pulse that turns on the brake thyristor. Since this pulse is amplified by the on-pulse amplifier 24A and applied to the gate of the brake thyristor 8, the brake thyristor 8 is fired during this period (T4 in FIG. 3).

During the firing period (T4), current flows through the brake thyristor 8, so the forward voltage during the period T3 shown in FIG. 2 disappears and becomes as shown in FIG. 3. Therefore, the brake thyristor 8 is turned off when the reverse voltage is applied during the period T2.

The pulse width T4 of the pulse 27 synchronized with the chopper-off pulse 26 must be appropriately selected so that it is not applied as an on-pulse when a reverse voltage is applied to the brake thyristor 8. Therefore, when the inductance of the commutating reactor 12 is L and the capacitance of the commutating capacitor 14 is C in FIG. 1, T4-πJLC/2 is set.

〔Effect of the invention〕

As described above, in the present invention, during the combined operation of regenerative brake control and dynamic brake control, an on-pulse is given to the brake thyristor in synchronization with an off-pulse to the chopper circuit, so when turning off the brake thyristor when the chopper is off, An incorrect forward voltage is not generated in the brake thyristor, so the voltage breakdown of the brake thyristor is prevented, and the switching between the dynamic brake control and the regenerative brake control can be smoothly performed. A chopper control device can be obtained.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a chopper control table U according to an embodiment of the present invention, FIGS. 2 and 3 are waveform diagrams explaining the operation of the device shown in FIG. 1, and FIG. 4 is an example of a conventional device. FIG. 5 is a waveform diagram illustrating the operation of the configuration example shown in FIG. 4. 1... Pantograph, 2.4.18... Unit switch, 3, 19... High speed circuit breaker, 5... Charging resistor, 6... Filter reactor, 7... Filter capacitor, 8... Brake thyristor, 9... Brake resistor, 10... Freewheeling diode, 1
1... Main thyristor, 12... Commutation reactor, 1
3... Auxiliary thyristor, 14... Commutation capacitor,
15... Main smoothing reactor, 16... Field coil,
17...Electric hoe coil, 20...Reducing current resistor.

Claims (1)

[Claims] In a chopper control device for an electric motor having a regenerative brake control function using a chopper circuit and a power generation brake control function using a power generation brake thyristor, during the combined operation of the regenerative brake control and the power generation brake control, the off pulse to the chopper circuit is synchronized. A chopper control device characterized by comprising means for applying an on-pulse to the thyristor for the electric power generation brake.