JPH10229683A - Control device for brake chopper - Google Patents

Abstract

(57) [Problem] To provide an electric vehicle that uses an alternating current as a power source to limit a regenerative electric power or a regenerative current to an overhead line using a brake chopper without interfering with DC voltage control of a converter. SOLUTION: A converter 4 connected to an AC power supply,
An inverter 2 connected to the motor, and a brake resistor 7 connected between the converter and the positive and negative DC connection of the inverter
And a brake chopper 6 in series, wherein the flow rate γ is calculated based on the regenerative power value P _B obtained by subtracting the regenerative power limit value P _R * from the calculated motor regenerative power P _MM to the overhead line. Controls the brake chopper by
The regenerative power value P _B is consumed by the brake resistor, and the remaining regenerative power P _R * is returned to the overhead line by the converter. [Effect] Since the brake chopper is controlled based on the power consumption of the brake resistor, it is possible to limit the regenerative power or regenerative current to the overhead wire while the converter controls the DC circuit voltage as in the past.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a brake chopper, and more particularly to a technique for using a brake chopper in an electric vehicle powered by alternating current to limit regenerative power or regenerative current to an overhead line.

[0002]

2. Description of the Related Art In recent years, a regenerative braking system has been put to practical use in an electric vehicle, in which an electric motor is used as a generator by using an inverter, the generated torque is used as a braking force, and the generated regenerative electric power is supplied to an overhead line. . In an electric vehicle powered by DC using the regenerative brake, if the regenerative brake is operated when the regenerative load is insufficient, the overhead line voltage will increase. A reversible regenerative / power-generating braking system, in which a regenerative brake and a power-generating brake are simultaneously actuated and the share ratio is changed according to a regenerative load, has been put into practical use. An example is shown on pages 231 to 234 of "Usage Symposium Transactions". FIG. 4 shows a regenerative / power generation blending brake using a brake chopper in a DC powered electric vehicle. During regeneration, the brake chopper 6 monitors the voltage of the filter capacitor 3, and when the voltage rises due to insufficient regenerative load, current starts flowing to the brake resistor 7,
Insufficient regenerative load is consumed by the power generation brake to suppress DC circuit voltage rise. If the regenerative load is further insufficient, the DC circuit voltage further increases. Therefore, the conduction ratio γ of the brake chopper is increased, and the increase in the current flowing to the brake resistor 7 suppresses the increase in the DC circuit voltage. Conversely, when the regenerative load increases, the conduction ratio γ is reduced, the power supply to the brake resistor 7 is reduced, and the DC circuit voltage is prevented from lowering. Thus, while the regenerative electric power from the motor 1 is maximized, the operation amount of the power generation brake is changed according to the fluctuation of the regenerative load, and the regenerative / power generation blending brake is operated. That is, a part of the regenerative electric power from the motor 1 is supplied by the brake chopper 6 to the brake resistor 7.
To limit the regenerative power or regenerative current that returns to the overhead line. On the other hand, there is no application example of the regenerative / power generation blending brake in an electric vehicle using AC as a power source, that is, an AC train and an AC / DC compatible train (hereinafter, both are collectively referred to as an AC train). However, Japanese Patent Application Laid-Open No. 5-30752 discloses a method of detecting a DC circuit voltage to be controlled by a PWM converter and simultaneously operating the PWM converter and a chopper to control the DC circuit voltage. Is the regeneration on the AC train
The configuration is substantially the same as the configuration of the power generation blending brake system, and can be applied to limiting the regenerative power returning to the overhead line.

[0003]

In the AC section of an AC train, there is a section in which a regenerative current is limited in order to prevent a malfunction of a distance relay in a substation. In such a section, even if an attempt is made to limit the regenerative current by applying the above-described conventional technology, there is a converter in an electric vehicle powered by AC, that is, an AC train, and at the time of regenerative power, an electric train is connected to an overhead line according to regenerative electric power from a motor. The regenerative current is controlled to keep the DC circuit voltage constant, so the brake chopper does not operate.
The regenerative power or regenerative current returning to the overhead line cannot be limited. Further, in the configuration disclosed in Japanese Patent Application Laid-Open No. Hei 5-30752, it is necessary to provide a means for performing DC voltage control in each of the PWM converter and the chopper, and to provide a means for associating and setting both so as to perform cooperative control. There is. That is, in the case where a chopper is added to an AC train which has not been equipped with a chopper, the control means of the converter has to be modified or changed in order to cooperatively control the chopper and the converter.

SUMMARY OF THE INVENTION An object of the present invention is to provide a brake chopper suitable for restricting regenerative electric power or regenerative current to an overhead line using a brake chopper without interfering with DC voltage control of a converter in an electric vehicle powered by AC. To provide a control device.

[0005]

An object of the present invention is to provide a power converter comprising a series body of a load and a brake chopper connected between positive and negative DC connections between a converter and an inverter,
In a control device for a brake chopper that controls a load to consume regenerative power from an inverter, when the regenerative power from the inverter reaches a predetermined value that is regenerated to an AC power supply by a converter, the regenerative power exceeds a predetermined value. This is solved by letting the load consume power. Further, in a power converter comprising a series body of a load and a brake chopper connected between a positive and negative DC connection of a converter and an inverter, the control device of the brake chopper performing control for consuming the regenerative current from the inverter to the load, When the regenerative current from the inverter reaches a predetermined value that is regenerated by the converter to the AC power supply, by supplying a regenerative current of a predetermined value or more to the load,
Will be resolved.

In the present invention, a brake chopper is provided in a DC circuit of a converter and an inverter of an AC train, and the brake chopper detects a DC circuit voltage to be controlled by the converter and does not control the voltage to a certain value. , Based on the power consumption or current of the brake resistor. As a result, a part of the regenerative electric power from the motor can be consumed by the brake resistor while the regenerative electric power from the motor is maximized without interfering with the DC circuit voltage control by the converter. The current can be limited.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a control device of a brake chopper showing one embodiment of the present invention. In FIG. 1, 1 is a motor, 2 is an inverter for converting DC power to AC power, 3 is a filter capacitor, 4 is a converter for converting AC power to DC power, and 5 is a main transformer (number of turns) connected to an AC power supply. Ratio N ₁ : N ₂ ), 6 is a brake chopper connected between the positive and negative DC connection of the converter 4 and the inverter 2,
7 is a brake resistor (load), 8 is motor regenerative power P _MM
An operation unit 9 is a gate start signal generation unit of the brake chopper 6, and 10 is a chopper conduction ratio γ operation unit.

Next, the operation of this embodiment will be described. First, the regenerative electric power P generated in the motor 1 during the regenerative braking
_MM is calculated by the motor regenerative power calculator 8. The motor regenerative power calculation unit 8 receives the motor phase current I _M , the motor line voltage V _m , and the motor power factor cos φ, and obtains the motor regenerative power P _MM using (Equation 1).

(Equation 1) Next, the limit value P _R * of the regenerative power that can be returned to the overhead line
And the difference between the motor regenerative power P _MM obtained by (Equation 1). This difference becomes the power consumption P _B of the brake resistor 7.
When the motor regenerative power P _MM is larger than the limit value P _R * of the regenerative power, the power consumption P _B of the brake resistor 7 becomes positive,
If this exceeds a certain value, the gate start signal generator 9
As a result, a gate start signal is generated, and the brake chopper 6 starts energizing the brake resistor 7. At this time, the duty ratio γ is calculated by inputting the power consumption P _B of the brake resistor 7 to the brake chopper duty ratio calculation unit 10 and is provided to the brake chopper 6. The conduction ratio gamma, determined by dividing, as shown in equation (2), the square root of the power P _B and the product of the brake resistor R _B of the brake resistor 7 in the DC circuit voltage E _d.

(Equation 2) The brake chopper 6 operates at the conduction ratio γ, and the power consumption P _B of the brake resistor 7, that is, the regenerative power limit value P _R * for returning to the overhead wire from the regenerative power P _MM from the motor 1 is subtracted (P _MM −P _R). *) Is consumed by the brake resistor 7, and the remaining regenerative power P _R * is returned to the overhead line by the converter 4. Also, the motor regenerative power P _MM is the regenerative power limit value P
If less than _R *, the power consumption P _B of the brake resistor 7
Becomes negative. At this time, the gate start signal is not output from the gate start signal generator 9 and the brake chopper 6
Do not work. The motor regenerative power P _MM
May be calculated from the DC voltage on the DC input side of the inverter and the DC current (during regeneration, the current direction is opposite to the current direction during power running) in addition to the expression (1).

FIG. 2 shows another embodiment of the present invention. This embodiment is different from the embodiment of FIG. 1 in the configuration of the regenerative power calculation unit, and the other configuration is the same. Overhead line regenerative power computing unit 11 of this embodiment receives the primary current I _P and trolley voltage E _P of the main transformer 5 detected, the regenerative power P _R to the actual overhead line on the basis of the equation (3) Is calculated.

(Equation 3) In the present embodiment, at the time of regenerative braking, a difference between the regenerative power P _R to the actual overhead line determined limit value of the regenerative power can be returned to the overhead wire P _R * and the equation (3). This is the power consumption P _B of the brake resistor 7. With respect to the power consumption P _B of the brake resistor 7, the same processing as in the embodiment of FIG. 1 is performed in the gate start signal generator 9 and the brake chopper duty ratio γ calculator 10. The brake chopper 6 operates according to the flow rate γ, and the brake resistor 7
Regenerative power limit consumption returning from the power P _B i.e. the regenerative power P _R to the actual overhead wire to the overhead line of minus P _R * (P _R -P _R
*) Is consumed by the brake resistor 7, and the remaining regenerative power P _R * is returned to the overhead line by the converter 4. In the present embodiment, instead of detecting the primary current I _P of the main transformer 5 directly, the secondary current I _S of the main transformer 5 to detect primary winding and secondary winding of turns ratio (N ₂ / N ₁₎
The over may be determined indirectly the primary current I _P.

FIG. 3 illustrates another embodiment of the present invention. In the present embodiment, as compared with the embodiment of FIG. 2, a limit value I _R * of a regenerative current to return to the overhead line is obtained instead of the limit value P _R * of the regenerative power to return to the overhead line, and the actual regenerative power P _{The difference is} that instead of _R , the actual regenerative current I _R to the overhead wire is detected, and that the brake chopper duty ratio γ calculation unit 10 calculates the duty ratio γ according to (Equation 4). The same is true. In the present embodiment, the difference between the limit value I _R * of the regenerative current that can be returned to the overhead line during regenerative braking and the detected actual regenerative current I _R to the overhead line is calculated. This is the current consumption I _B of the brake resistor 7. When the actual regenerative current I _R to the overhead wire is larger than the regenerative current limit value I _R *,
It becomes consumed current I _B positive brake resistor 7, once exceeded this is a value, to generate a gate start signal by the gate start signal generating unit 9, a brake chopper 6 starts energizing the brake resistor 7. Conduction ratio at this time γ is calculated by entering the quiescent current I _B of the brake resistor 7 to the brake chopper duty ratio calculation unit 10 gives to the brake chopper 6. The conduction ratio γ is, as shown in (Equation 4),
Determined by dividing the square root of the product of consumed current I _B and the brake resistor R _B and the overhead line voltage E _P of the brake resistor at a DC circuit voltage E _d.

(Equation 4) Brake chopper 6 is operated by Tsuryuritsu gamma, minus the regenerative current limiting value I _R * to return from the regenerative current I _R of the consumed current I _B That actual overhead wire brake resistor 7 to the overhead line (I _R -I _R *) is consumed by the brake resistor 7, and the remaining regenerative current I _R * returns to the overhead line by the converter 4. When the actual regenerative current I _R to the overhead wire is smaller than the regenerative current limit value I _R *, the current I _B consumed by the brake resistor 7 becomes negative. At this time, the gate start signal is not output from the gate start signal generator 9 and the brake chopper 6 is not operated.

[0011] Incidentally, in the embodiment shown in FIG. 1, FIG. 2, a regenerative power limit value P _R * to the overhead line, replacing the product of the regenerative current limiting value I _R * and trolley voltage E _P to the contact wire Also, the present invention can be applied. Also, in the embodiment shown in FIGS. 1, 2 and 3, the converter 4, the inverter 2, and the brake chopper 6 are each connected to one main transformer 5.
Although the number of these devices is arbitrary, the brake chopper 6 can control the power consumption or current of the brake resistor 7 serving as the load, and the present invention is applied. Can be.

[0012]

As described above, according to the present invention,
Since the brake chopper is controlled based on the power consumption of the brake resistor, the converter controls the DC circuit voltage as before and maximizes the regenerative power from the motor while regenerative power to the overhead wire or Regenerative current can be limited. Thus, even in an AC section where the regenerative power or the regenerative current is limited, the vehicle can be driven with the regenerative brake applied in the same manner as in the normal section. Also, the brake chopper is not a DC circuit voltage,
By controlling based on the power consumption of the brake resistor, a portion of the regenerative power from the motor can be consumed by the brake resistor without interfering with the DC circuit voltage control by the converter. In addition, the regenerative electric power or regenerative current to the overhead wire can be limited without changing the converter control means depending on the presence or absence of the chopper device.

[Brief description of the drawings]

FIG. 1 is a control apparatus of a brake chopper showing an embodiment of the present invention.

FIG. 2 shows another embodiment of the present invention.

FIG. 3 shows another embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Motor 2 Inverter 3 Filter capacitor 4 Converter 5 Main transformer 6 Brake chopper 7 Brake resistor 8 Motor regenerative power P _MM calculation unit 9 Brake chopper gate start signal generation unit 10 Brake chopper duty ratio γ calculation unit 11 Overhead wire regenerative power P _R operation unit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02M 7/155 H02M 7/155 E 7/48 7/48 E

Claims (2)

[Claims] A converter connected to an AC power supply for converting AC power into DC power; an inverter for converting the DC power into AC power and supplying the AC power to a motor;
A power converter including a series connection of a load and a brake chopper connected between a positive and negative DC connection of the converter and the inverter, wherein the control device controls a brake chopper that controls the load to consume regenerative power from the inverter. In the brake chopper, wherein when the regenerative power from the inverter reaches a predetermined value that is regenerated to an AC power supply by the converter, regenerative power equal to or more than the predetermined value is consumed by the load. Control device. 2. A converter connected to an AC power supply for converting AC power into DC power, an inverter for converting the DC power into AC power and supplying the AC power to a motor,
A power converter including a series connection of a load and a brake chopper connected between positive and negative DC connections of the converter and the inverter, the control device for a brake chopper performing control to consume regenerative current from the inverter to the load. The brake chopper according to claim 1, wherein when a regenerative current from the inverter reaches a predetermined value that is regenerated by the converter to an AC power supply, a regenerative current equal to or more than the predetermined value is supplied to the load. Control device.