JPH03190565A - Phase controller for power converter - Google Patents

Abstract

PURPOSE:To suppress abnormal operation of a power converter and influence thereof onto the load side by normally selecting a first phase control means corresponding to a power supply system being supplied with power through a power supply bus, whereas selecting a second phase control means at the time of switching of the power supply system, and providing a phase control signal to a power converter. CONSTITUTION:When power supply is switched from first power supply system 10 to second power supply system 20, secondary circuit breaker 12 in the first power supply system 10 is opened at first. Consequently, closing signals for both secondary circuit breakers 12, 22, provided from a selection circuit 3, go to 0 and a signal for selecting a contact 5b is provided from the selection circuit 3 thus closing the contact 5b. subsequent closing of the secondary circuit breaker 22 is detected by the selection circuit 3, which then closes a contact 5c and selects a phase control circuit 4c, and the phase of a power converter 2 is controlled based on an output signal from the phase control circuit 4.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention converts power supplied from a power bus bar connected to a plurality of power supply systems via a circuit breaker into predetermined power. The present invention relates to a phase control device for a power converter that can control the phase applied to a load.

(Prior Art) For example, in a highly public power generation plant, when an abnormality occurs in a power supply system, a method is adopted in which the power supply is disconnected and switched to another power supply system, and control thereof is continued.

FIG. 3 shows an example of the configuration of such a power supply system. As shown in FIG. 3, the first power supply system 10 and the second power supply system 20 have a main transformer 11 that steps down the system voltage.
．． 21 and the power supply bus 60 via its secondary circuit breakers 12 and 22, respectively. This [source bus 60
A power converter 2 is connected to the power converter 2 via a breaker 1, and the speed of a motor 9 is controlled by the output of the power converter 2.

Further, a phase control circuit 4b is connected to the power supply bus 60 via a transformer 6 that detects the bus 1jl voltage, and this phase control circuit 4 controls the power converter according to the phase of the bus voltage detected by the transformer 6. 2 is phase controlled.

Further, the bus voltage 60 is connected to the electric motor 8 via the circuit breaker 7.
is connected.

FIG. 4 shows the internal configuration of the power converter 2. In FIG. 4, 2a-1 to 2a-6 are thyristors whose phases are controlled by the outputs f and j of the control circuit 4J) and which convert AC power supplied via the circuit breaker 1 into DC power; 2e-1 is a DC reactor that smoothes this DC power, and 2b-1 to 2b-6 are DC reactors 2e-
2d-1 to 2d-6 are commutating capacitors that store the commutating energy of the thyristors 2b-1 to 2b-6; 2cm6 is a diode which separates the terminal voltage of the commutating capacitors 2d-1 to 2d-6 and the motor 9.

The operation of the power converter 2 having such a configuration is described in detail in, for example, "New Drive Electronics" (published by Denki Shoin, edited by Naohiko Yamagami), chapter m4, P103 to P109, so the explanation thereof will be omitted here.

Further, FIG. 5 shows a detailed configuration of the phase control circuit 4b. As shown in FIG. 5, the output signal 6e-1 of the transformer 6 for detecting the voltage phase of the power supply bus 60 is input, and a filter 4b-1 is used for the purpose of preventing disturbance from the power supply bus 60. A comparator 4b-2 detects the zero cross of the AC signal output from 4b-1 and converts it into a pulse waveform with a duty of 50%, and the output signal of this comparator 4b-2 and a gate pulse generator 4b-9 to be described later. A resistor that inputs the synchronizing pulse signal from the gate pulse generator 4b-3 and 4b-4 through the resistors 4b-3 and 4b-4, and integrates the phase difference between the output signal of the comparator 4b-2 and the synchronizing pulse signal from the gate pulse generator 4b-9. 4b-5, a capacitor 4b-7, and an amplifier 4b-6. An oscillator 4b-8 that oscillates at an arbitrary frequency based on the output signal of this proportional-integral circuit. Operates based on the oscillation frequency of this oscillator 4b-8. It consists of a gate pulse generator 4b-9 whose time is determined.

In the power supply system having such a configuration, it is assumed that the secondary circuit breaker 12 of the first power supply system 10 is now turned on, and the secondary circuit breaker 22 of the second power supply system 20 is in an open state. . In such a state, when switching the power from the first power system 10 to the second power system 20, first the secondary side breaker 1 of the first power system 10 is switched.
Open 2. As a result, the voltage and frequency of the power supply bus 60 become the terminal voltage of the electric motor 8 connected via the breaker 7. This terminal voltage is determined by the energy stored in the motor 8 and its load.

Therefore, when the secondary circuit breakers 12 and 22 are both opened, the voltage and frequency of the power supply bus 60 gradually decrease. In such a state, the secondary side cutter 22
When the power supply bus 60 is turned on, the voltage and frequency of the power supply bus 60 suddenly change because the secondary voltage and frequency of the transformer 21 are the same as the values of the power supply bus 60 before the secondary side breaker 12 is opened. As a result, the phase control circuit 4b cannot operate normally because it receives the voltage phase detection signal of the power supply bus 60.

(Issue 1m to be solved by the invention) In such a conventional power converter phase control device, if the voltage and frequency of the power supply bus suddenly change when switching the power supply system, the phase control circuit will not be able to operate normally. There were the following problems.

(1) When a power supply switch occurs, the main circuit phase changes instantaneously, but the gate pulse phase, which is the output of the phase control circuit, follows with a delay of the response time of the proportional-integral circuit inside the phase $Ila circuit, so - The output power of the power converter (here, the rectifier) increases or decreases from time to time, leading to overcurrent or the like depending on the case, which has a large impact on the load side.

(2) If the phase change is very large, the proportional-integral circuit inside the phase control circuit becomes saturated, and the phase control circuit becomes inoperable.

(3) Depending on the phase control state when power supply switching occurs, the relationship between the main circuit phase and the control circuit phase may exceed the phase control range relationship due to a delay in tracking the phase control, resulting in arc loss or commutation failure. reach. If the rectifier is operated in regeneration mode at this time, it will cause a load short circuit, causing damage to the equipment and load-side equipment.

The present invention instantly synchronizes the main circuit phase and the control circuit phase at the same time as the main circuit power supply is switched, and suppresses the abnormal operation of the power converter and the influence on load side equipment etc. due to the sudden phase change that occurs when the power supply is switched. The purpose of the present invention is to provide a phase control device for a power converter that can perform the following steps.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention connects a load that is connected to a plurality of power supply systems via a breaker and is capable of regenerating energy. A phase control device for a power converter capable of controlling the phase of converting power supplied from a power supply bus into predetermined power and supplying the same to a load, comprising: a first voltage detection means for detecting the voltage phase of each power supply system; , a second voltage detection means for detecting the voltage phase of the power supply bus; and a second voltage detection means provided corresponding to each of the power supply systems, and
a first phase control means to which a voltage phase detection signal of each power supply system detected by the voltage detection means of the second phase control means is input;
a second phase control means to which a voltage phase detection signal of the power supply bus detected by the voltage detection means of the power supply bus is inputted, and opening/closing information of the circuit breaker on each power supply system side is inputted; The first power supply system corresponding to
and selecting means for selecting the second phase control means when switching the power supply system and applying the phase control signal to the power converter.

(Function) Therefore, when the power converter is phase-controlled by the first phase control means corresponding to the power supply system in which the power converter is configured as described above, when the power supply system is switched, the power supply bus is controlled by the selection means. The second phase control means is selected by determining from the opening/closing information of the circuit breaker that no power supply system is connected to the second phase control means. Thereby, this second phase control means can follow the phenomenon in which the voltage of the power supply bus and its frequency gradually decrease. In addition, when another power system is connected to the power bus in such a state, the selection means determines this from the opening/closing information of the circuit breaker and selects the first power system corresponding to the power system connected to the power bus.
Since the phase control means is selected, it is possible to follow sudden changes in the voltage and frequency of the power supply bus that occur due to switching of the power supply system.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of a phase control device for a power converter according to the present invention. The same parts as in FIG. 3 are given the same symbols, and the explanation thereof will be omitted, and only the different points will be described here. In this embodiment, as shown in FIG.
a s 4 c are provided, and the phase control circuit 4a receives the secondary side voltage phase of the transformer 11 on the first power system 10 side detected by the transformer 13, and the phase control circuit 4C receives the transformer The secondary side voltage phase of the transformer 21 on the second power supply system 20 side detected by the transformer 23 is inputted, and the output signals of these phase control circuits 4a and 4c are input to the phase control circuit 4b.
Contacts 5a and 5c are selectively switched by a selection circuit 3, which will be described later, together with an output signal from the contact points 5a and 5c.

5b, it is configured to be given as a control signal to the power converter 2.

As shown in FIG. 2, the selection circuit 3 is a NOT circuit 3 that inverts the signal level "1" upon receiving the closing signal 22e1 of the secondary side breaker 22 of the transformer 21 of the first power supply system 2.
a s NOT circuit 3b, which inverts the signal level "1#" when receiving the closing signal 12e1 of the secondary side breaker 12 of the transformer 11 of the first power supply system 10, and the closing signal 12el.

22e1 are both “0”, that is, the secondary side breaker 1
2. AND outputs selection signal 5be when 22 is in open state
Circuit 3d, input signal 12e is “1”, input signal 22e
1 is "0°," that is, when the secondary circuit breaker 12 is in the closed state and the secondary circuit breaker 22 is in the open state, the selection signal 5
AND circuit 3c that outputs ae, when the input signal 12e is "0" and the input signal 22e1 is "1", that is, when the secondary side is 9
The AND circuits 3d and 3c are composed of an AND circuit 3e that outputs a selection signal 5ce when the circuit breaker 812 is open and the secondary circuit breaker 22 is closed.

When the output signal level of 3e is “1”, the corresponding contact 5
b, 5a, and 5c are designed to form a closed circuit.

Next, the operation of the power converter phase control device configured as described above will be described.

Now, the secondary side breaker 12 of the first power supply system 10 is turned on, and the secondary side breaker 22 of the second power supply system 20 is turned on.
It is assumed that the power converter 2 is in a state where it is open and the phase of the power converter 2 is controlled by the phase control circuit 4a. In such a state, when the power is switched from the first power system 10 to the second power system 2o, the secondary circuit breaker 12 of the first power system 10 is first opened. Then, the closing signals of the secondary side breaker 12゜22 inputted to the selection circuit 3 both become "0", so the selection circuit 3 outputs the contact 5b.
A signal is output to select , and contact 5b is closed. As a result, the power supply bus 60 becomes the terminal voltage of the motor 8, and the phase control circuit 4b receives the voltage and frequency.
The phase of the power converter 2 is controlled by the output signal of the power converter 2, and it is possible to follow the phenomenon in which the voltage frequency of the power supply bus 60 gradually decreases.

Next, when the secondary circuit breaker 22 is turned on in such a state, this is detected by the selection circuit 3, and the phase control circuit 4c is selected by closing the contact 5C, and the output signal of the secondary circuit breaker 22 is detected by the selection circuit 3. is phase controlled. This makes it possible to follow sudden changes in the voltage and frequency of the power supply bus 6o.

In this way, in this embodiment, in addition to the phase control circuit 4b that follows the voltage and frequency of the power supply bus 60, the phase control circuit 4a that follows the voltage and frequency of the first power supply system 10 and the second
A phase control circuit 4c that follows the voltage and frequency of the power supply system 20 is provided, and a selection circuit 3 to which the closing signal of the secondary side breaker 12.22 is input is provided.
closing signal 12e1 and closing signal 2 of the secondary side breaker 22
2e1 is input and input signals 12e1 and 22e1 are both "
0", the AND circuit 3d outputs the selection signal 5be, and when the closing signal of the secondary side breaker 12 is in the "1" state and the closing signal of the secondary side breaker 22 is in the "0" state, the AND circuit 3d outputs the selection signal 5be. The selection signal 5ce is output from the circuit 3e, and the input signal 12e1 is "0" and the input signal 22e1 is "1".
When #, the selection signal 5ae is output from the AND circuit 3C to select the phase control circuits 4b, 4al, and 4c, and the output signal is used to control the phase of the power converter 2, resulting in the following effects. be able to. (a) By selecting the optimal phase control circuit for each power supply switch,
This can be achieved without stopping the operation of the equipment.

(b) The control circuit phase can always be synchronized with the main circuit phase even if a sudden transient phase change occurs when switching the power supply.

(c) Since the phases of the main circuit and control circuit are always synchronized, the main circuit and! Arc loss and commutation failure caused by a phase shift in the control circuit can be prevented even when switching the power supply.

[Effects of the Invention] As described above, according to the present invention, the main circuit phase and the phase of the 1# control circuit are instantaneously synchronized at the same time as the main circuit power supply is switched, and the power converter is able to avoid sudden phase changes that occur when the power supply is switched. It is possible to provide a highly reliable phase control device for a power converter that can suppress abnormal operation of the power converter and its influence on load-side equipment.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of a phase control device for a power converter according to the present invention, FIG. 2 is a configuration diagram of a selection circuit in the same embodiment, and FIG. 3 is a conventional phase control diagram for a power converter. FIG. 4 is a circuit diagram showing the internal structure of the power converter, and FIG. 5 is a block diagram showing the internal structure of the phase control circuit. DESCRIPTION OF SYMBOLS 1... Breaker, 2... Power converter, 3... Selection circuit, 4a-4c... Phase control circuit, 5a-5c...
・Contact, 6... Transformer, 7... Breaker, 8, 9.
...Electric motor, 10, '20...1st. 2nd power supply system, 11, 21° 23... transformer, 12.22... secondary side breaker, 60... power supply bus.

Claims (1)

[Claims] A phase-controllable power conversion system that is connected to multiple power supply systems via circuit breakers and is connected to a load that can regenerate energy, converting the power supplied from the power supply bus into predetermined power and supplying it to the load. In the phase control device for the power supply system, a first voltage detection means for detecting the voltage phase of each of the power supply systems, a second voltage detection means for detecting the voltage phase of the power supply bus, and a first voltage detection means for detecting the voltage phase of the power supply bus, each of which corresponds to each of the power supply systems. a first phase control means, which is provided respectively in the first phase control means, into which a voltage phase detection signal of each power supply system detected by the first voltage detection means is input; and the power supply bus line, which is detected by the second voltage detection means. a second phase control means into which a voltage phase detection signal is input; and a first phase control means into which opening/closing information of the circuit breaker on each power supply system side is input, and which corresponds to the power supply system normally supplied through the power supply bus. a selection means for selecting a control means, selecting the second phase control means at the time of switching the power supply system, and supplying the phase control signal to the power converter; Control device.