JPS63202236A - Momentary-discontinuity-proof source changing switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a power supply changeover switch for switching from one power source to another power source without momentary interruption for a load requiring no momentary interruption.

(Conventional technology) Conventionally, a power switching swing using a thyristor was used (
When switching the AC power source for a load, as is well known, due to the ignition characteristics of the Nyristor, an instantaneous interruption of more than half a cycle of the AC power source is required to prevent galvanism. Therefore,
In order to switch the AC power supply without momentary interruption (and without generating excessive cross current), it was necessary to precisely control the voltage and phase of the AC power supply using a phase control device. .

(Problems to be Solved by the Invention) The above-mentioned phase control device for switching the AC power supply without momentary interruption and without generating excessive cross current using the above-mentioned conventional power supply changeover switch is configured as described above. It is necessary to precisely control the voltage and phase of the AC power supply to prevent excessive galvanic current from flowing between the thyristors connected to each phase, and to minimize voltage fluctuations during switching. However, there were problems in that the circuit configuration was complex and extremely expensive. −
・On the other hand, if the AC power supply is switched without controlling the voltage and phase mentioned above in order to configure the power supply changeover switch at low cost, the cross current phenomenon described in iyI will naturally occur - [the power supply switch will be destroyed, and the AC power supply will be damaged]. There was a problem in that the device itself could be destroyed.

In the present invention, C detects the direction of the load current when the load current is being applied to the load from one AC power source, and when a power supply switching signal is output from the outside,
The bidirectional AC power control element is controlled so that the load current in the same direction as the load current flowing from the AC power supply before switching to the load is energized from the AC power supply after switching without momentary interruption.φ
The technical problem to be solved is to provide an inexpensive uninterrupted power changeover switch with a cylindrical structure that does not avoid generation of excessive cross current.

(Means for solving the problem) The first technical step to solving the above problem is when an external power supply switching signal is input while the load current is being applied from the AC power supply to the negative voltage source. , while cutting off current to the load from the AC power source Δ, passing current to the load from another AC power source B in accordance with the direction of the load current immediately before the current interruption Igi to the AC power source without momentary interruption; A bidirectional AC power 1/l 111 element As connected to each phase of the AC power supply, and a bidirectional AC power connected to each phase of the AC power supply! II
１０ When # distribution power switching signal is input in the process of inputting , the output of the energization control signal to the bidirectional AC power control element As is temporarily stopped to cut off the energization from the AC power source to the load, while the power source is Gate control for outputting an energization control signal (to the bidirectional AC power control element 83) to cause the AC power source B to energize the load without momentary interruption in a current according to the direction of the load current immediately before the switching signal is input. There is a configuration that includes means.

(Action of the invention) No flash 1i with the above configuration? ! According to the E source changeover switch, when the load is energized from the AC power supply via the bidirectional AC power tiIIIall element AS, the load current detection means detects the magnitude of the load current for each phase. A corresponding signal is output to said gate Ill 60 means.

a gate i into which the signal from the seasonal load current detection means is input;
The II all output means outputs an energization control signal to the bidirectional AC power control element AS until an external power supply switching signal is input, while when the power supply switching signal is input, the gates i and II a output Bidirectional AC power control element△
Stop outputting the communication ff1ilJIII signal to S,
It cuts off the current flow from the AC power supply to the load, and outputs to the bidirectional AC power control element BS an energization control signal 8 corresponding to the current flow direction of the load current immediately before switching the AC power supply, and the bidirectional AC power control element 88 is turned on and the load current is passed from the L1 AC power supply B to the load without momentary interruption.

(Example) Next, an example of the present invention will be described with reference to the drawings. 1st
The figure is an overall electrical system diagram for explaining an embodiment of the present invention. As shown in the figure, three-phase AC power supply A and AC power supply B each have bidirectional thyristor blocks As%.
BS is connected.

Although the AC power source and the AC power source B have the same output voltage and frequency rating, precise phase control is not performed to control the phase of the output voltage of each power source.

In addition, as shown in the figure, the bidirectional sirisk block As connected to the AC power supply A is connected to the ( ) phase, ■ phase,
Thyristors UIA' and U2A connected to each W phase
, V1A, V2A, WlA, and W2Δ, and the bidirectional 1 Nyristor block BS connected to AC power supply B is the U phase of AC power supply B.

Thyristors U1B and L connected to the ■phase and W phase, respectively.
It has J2B, VIB, V2B, WlB, and W2B. The U, ■, and W phases of the bidirectional thyristor blocks As and BS are connected to the connection points UP and V on the opposite power supply side for each phase.
Connected with P and WP, one tree power supply IUL and VL for each phase
, WL and connected to the load.

A current transformer (current transformer) CT1. CT2 and CT3 are inductively coupled. These current transformers CT1. CT2.
CT3 outputs a voltage signal corresponding to the direction and magnitude of the current, and this voltage signal is input to the current direction signal output circuit 1 for each phase by current transformers CT1. CT2
．． The secondary side of CT3 is connected to current direction signal output circuit 1.

As shown in Fig. 2, the current direction signal output circuit 1 is composed of comparators Ol) 1 and OF2 for zero comparison in each phase, and a phase inverting knob INV. A signal is applied to the non-inverting input terminal of Combare/1oP1 and the phase-inverting cable IN
It is also input to V.

Therefore, the current transformer CT that can be input to the phase inversion element INV
The output signal of I is applied to the non-inverting input terminal of the comparator OP2 with the phase of the phase inverting element INV'c being inverted.

The output signals of the comparators OP1 and OP2 are input to the gate control circuit 2. As shown in Fig. 2, gate control +@path 2 generates a signal from channel 11 channel collector 2Δ jump -1 for each phase as shown in Fig. 2! [Construction of vessel 2B.

The channel selector 2A and the gate signal generator 2B are each composed of the same circuit for each phase, and the specific circuit is shown in FIG. 1. As shown in FIG. 3, the channel selector 2△ is a two-input AND element AND1. AND2.
ΔAND3 and AND4 and external power supply switching signal P
It is composed of a frame 1 for inputting a CH to an element NOT. The output terminal of the comparator OP1 is an AND element ANr)1
and AND2, while the output terminal of the comparator OP2 is connected to AND elements AND3 and AND4.
connected to the input terminal of Also, knot element N.

The output terminal of the output terminal is connected to the input terminals of the AND elements ANDI and AND3, while the power supply switching signal PCI, which is not inverted by the NOT element NOT, is connected to the input terminals of the AND elements AND2 and ΔND4.
is applied directly to the input terminal of

J5, the power supply switching signal PCH input from the outside has the form of a logic signal "0" or "1", and if the power supply switching signal PCH is a logic signal rOJ, each thyristor of the thyristor block AS is This serves as a condition signal for making each thyristor of the Nyristor block BS conductive, and when the power supply switching signal PCH is a logic signal "1", it serves as a condition signal for making each thyristor of the Nyristor block BS conductive.

The AND element AND1. AND2. ΔAND3゜AND
The output terminal of 4 is connected to the gate signal generator 2 as shown in FIG.
Connected to B. For example, the signal generator 2B includes a high frequency generator ff1ll-IFI to HF4 and a pulse transformer P.
T1 to PT4 and a rectifier (not shown) are provided. That is, the gate signal Y'i generator 2B is equipped with a high-frequency oscillator (I F 1 to HF4), whose oscillation output is insulated by pulse lances P T 1 to PT4, and is roughly connected to a rectifier (not shown). By rectifying the signal, pulse-like gate signals 17'C as shown in FIG. 4 (E) to (B) to be described later are generated. Furthermore, the high frequency oscillator IF1~IIF4I and the AND element ANDI~
The circuit is formed such that when the output signal of AND4 is 1"1", the corresponding high frequency oscillator Hr:1.1-IF4 outputs an oscillation signal. On the other hand, game 1- (
The output side of i\2j generation 'a2B is the thyristor UIA.
S first controller U1B.

It is connected to the gate terminals of the thyristor U2Δ and the nyristor U2B. Therefore C1 gate signal generator 2B
When a pulse 1≦ is output from the thyristor, this pulse signal is applied to the gate terminal of the corresponding thyristor as a gate signal for the thyristor, thereby firing the thyristor.

Note that the circuits of the channel selector 2△ and the gate signal generator 2B shown in Fig. 3 only show the components related to the U phase, but the above circuit is also the same circuit for the ■ phase and the W phase. It is configured.

With the circuit configuration shown below, the current transformer CT1 detects the load current flowing through the feeder line UL-, and the current transformer CT1
T2 is the power supply 11V1. The current transformer CT3 roughly detects the load current flowing through the feeder line WL, and outputs a voltage signal corresponding to the magnitude and direction of the detected load current as a current direction signal for each phase. Output to circuit 1. The current direction signal output circuit 1 includes current transformers CT1 for each phase.
The voltage signal output from CT 3 is inputted and converted by comparator OP1 into a zero-comparison combiner 1~ signal that does not invert the phase, and a phase inverter INV.
The comparator o[]2 converts the phase of the zero comparison into a humbalate signal that avoids inversion, and outputs it to the gate control circuit 2. The control circuits 1 to 2 generate an AND signal of the power supply switching signal PCH and the comparison signal or the phase-inverted comparison signal, and output the AND signal through high frequency oscillators HFI to HF4, pulse transformers PTI to PT4, and a rectifier (not shown). °C corresponding thyristor goo 1
Apply to one terminal to avoid firing the corresponding one Nyristor.

In this state, the power supply switching signal>Jp CH signal changes from, for example, a logic signal "0" to "1", thereby changing the power supply from the AC power supply to the AC power supply 131. : When a switching command is output, the gate signal from the gate control circuit 2 is output to the thyristor of the bidirectional thyristor block BS. Goo1 to i11 at the above power supply switching timing
The circuit 2 aIlltlIl the gate of the bidirectional thyristor block O8 so that the load current in the same direction as the negative f1 current that has been passed from the AC power supply to the load flows from the AC power supply B to the load.

The timing when switching the power supply F will be specifically explained based on the timing chart of FIG. 4. However, the total timing chart shown in FIG. 4 is for one phase, for example, the U phase, and the timing characteristics are similar to b in the case of the V phase and the W phase.

In Figure 4, (a) shows the six waveforms of the output signals from the current transformer CTI, with the upper part (+) and the lower part (-) of the current transformer CTI.
), the thyristor U2Δ is conductive when it is (+). That is, in the U phase, current flows from the power supply to the load in C. At (-) time, thyristor L11A is conductive. In other words, in the U phase, current flows from the load toward the power source. This output signal is output from the comparator O
Applied to the non-inverting input terminal of P1. Also, (opening) is a signal waveform obtained by inverting the output signal of the current transformer CTI by the phase inverting cable INV, and this phase inverting signal is applied to the non-inverting input terminal of the comparator OP2. (C) is the output signal q of the comparator OP1 which is zero-compared with the signal (A) by the comparator OP1, and is simultaneously applied to the input terminals of the AND circuits ANDI and AND2 of the channel selector 2A. (D) is the output signal of the comparator OP2 which is zero-compared with the signal (B) by the comparator OP2, and is simultaneously applied to the input terminals of the AND4 of the channel selector 2Δ. (e) When the power supply switching signal PCH is logic [01, that is,
When specifying AC power supply A and applying load current to the load, the AND element ANDI of channel selector 2Δ
A logic “1” signal is output from the high frequency light 1 [HF
The waveform of the gate signal output from the gate signal generator 2[3 to the gate of the thyristor U1A while the oscillation No. 11 is being output from the gate signal generator 2[3] is shown below.

Also, (to) the power supply switching signal PCH is the logic]! T! rOJ
When , the AND element △ND3 of channel selector 2Δ
A logic “1” signal is output from the high frequency oscillator HF.
This is a waveform of a gate signal outputted from the signal generator 2B to Goo 1 to Goo 1 of thyristor U2Δ while an oscillation signal is being output from Goo 3.

Next, at timing T shown in (a), in order to switch the power supply for the C1 load from AC power supply A to AC power supply B, when the power supply switching signal PCH changes from logic "0" to "1", the Since the output No. 15 of the NOT TOYO NOT of the Busennel selector 2Δ shown in FIG. 3 is inverted, the AND elements AND2 and AND4 become active. In this state, since the output of the comparator OP2 is logic "1" as shown in C (d), a logic "1" signal is output from the AND element AND4, and an oscillation signal is output from the high frequency oscillator HF4. Gate signal generator 2
The gate signals shown from B to (H) are the thyristor U2.
It is output to the gate of B.

That is, when switching the power supply as described in -H, the direction of the load current relative to the load is controlled to be the same direction before and after switching.

(1~), when the power-off signal PCH is logic "1", a logic "1" signal is output from the AND element ΔND2 of the channel 1/channel selector 2A, and the high frequency oscillator IF2
Gate signal generation 4 while the oscillation signal is being output from
This is the waveform of the gate signal output to the gate of 2B Karairiristor (J 1 B).

As described above, when a power supply switching command is issued from the outside and the power supply is switched from AC power supply A to AC power supply B, both sides are set so that the load current flows in the same direction as the load current before switching even after switching. Since the thyristor block is controlled in one direction, almost no cross current of /V flows between the thyristors, and no instantaneous interruption occurs during switching. This situation is the same for the V phase and W phase, and the power supply is AC 111G.
A similar operation is performed when switching from IB to AC power supply.

J3, an example of a three-phase power supply is shown as an example, but if the power supply and negative 1 are single-phase, and if there is a multi-phase power supply with four or more phases, the same effect as 'b' can be achieved by switching the power supply. . Further, in the case of a three-phase power supply, for example λ, the V phase of the power supply may be directly connected to the load without switch control, and the thyristor of the ■ phase may be omitted. Therefore (generally, if the power supply is N-phase, (N
-1) It is possible to realize F2 negative use using a set of bidirectional thyristors.

(Effects of the Invention) As described above, according to the present invention, the current direction of the load current from the AC power supply to the load is detected at each phase angle, and when a power supply switching signal is output from the outside, the load current before switching is detected. The bidirectional AC power control element is controlled so that the load current in the same direction as the energization direction of the thyristor is energized without momentary interruption from the AC power supply after switching, preventing the generation of excessive cross current, and controlling the thyristor's AC power. This has the effect that an uninterrupted power supply changeover switch that can prevent element destruction can be provided at a low cost with a simple structure.

[Brief explanation of the drawing]

FIG. 1 is an overall electrical system diagram of one embodiment of the present invention, and FIG.
The figure is an electric circuit diagram showing details of the current direction signal output circuit shown in Fig. 1, Fig. 3 is an electric circuit diagram showing details of the gate control circuit shown in Fig. 1, and Fig. 4 is an embodiment example. It is a figure to timing chart 1 for explaining the effect|action of this figure. 1...Current signal generator 2...Gate control circuit 2A...Channel selector 2B...Gate signal generator As, BS...Bidirectional thyristor block CT1. C
70, CT3...Current transformer L...Load

Claims (1)

[Claims] When an external power supply switching signal is input while a load current is being applied to the load from the AC power source A, the current to the load is cut off from the AC power source A, while immediately before the AC power source A is cut off. An uninterruptible power supply changeover switch that allows a load current to flow in accordance with the direction of the load current from another AC power supply B to the load without momentary interruption, the bidirectional switch being connected to each phase of the AC power supply A. AC power control element A
S, a bidirectional AC power control element BS connected to the AC power source B, and a load current detector that detects the load current for each phase and outputs a signal corresponding to the magnitude and direction of the load current of each phase. and when the power supply switching signal is input during the process of inputting the signal output from the load current detection means, the output of the energization control signal to the bidirectional AC power control element AS is stopped, and the output of the energization control signal to the bidirectional AC power control element AS is stopped. energization control signal to cut off the energization to the load from the AC power source B and to cause the AC power source B to energize the load without instantaneous interruption according to the direction of the load current immediately before the power supply switching signal is input. 1. A non-interruptible power supply changeover switch comprising: gate control means for outputting to a counter AC power control element BS.