JPS5883525A - Ac no-break power source - 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 The present invention relates to an AC uninterruptible power supply using a magnetic saturation type constant voltage transformer (hereinafter referred to as a three-winding transformer) having a three-winding magnetic shunt, and more specifically, the present invention relates to an AC uninterruptible power supply device that uses a magnetic saturation type constant voltage transformer (hereinafter referred to as a three-turn transformer) having a three-winding magnetic shunt. A control circuit that instantly detects a power outage and instantly advances the inverter phase at the same time to eliminate transient fluctuations in output voltage that occur when a power outage occurs. This relates to a control circuit that turns on commercial power in the same phase as the inverter in order to eliminate this.

FIG. 1 shows a block diagram of an AC uninterruptible power supply using a 3S transformer, and its operation will be explained.

In Figure 1, when the commercial power supply is normal, the power is from the 1st winding (6-1) of the sirisk switch (51-3s) lance (6) to the 3rd s line (6-3) to the load. (7)
are supplied in this order. In addition, the other one is the second of the charger (2) - storage battery (4) - inverter (3) 13-turn transformer (6).
It is supplied in the order of winding (6-2) -> third winding (6-3) -> load (7). In other words, the inverter (3) is operated in synchronization with the commercial power supply (1) and the power from both is transferred to the three-turn transformer (
6) to combine and supply to the load (7). In this case, if the phase of the AC voltage converted by the inverter (3) is adjusted to the same phase as the AC output voltage applied to the load (7), the flow of power from the inverter (3) to the load (7) becomes zero. The inverter goes into a standby state. This state will be explained in detail using an idealized circuit of a three-turn transformer shown in FIG.

In FIG. 2, Ll and L2 are the leakage inductances obtained by the two magnetic shunts, and C is the resonance capacitance. The current commercial power supply voltage is M inverter voltage.
N, and if these have the same frequency and phase angles of φ1 and φ2, respectively, for output voltage < 10, then V
o==V o −.

From the circuit calculation, the power P1 and P2 supplied from each power source is P L = (VAcV o /'ωLl) sin
φIP2= (V, N't10/ωl, s in
It becomes φ2. Therefore, if the phase of the inverter is adjusted so that φ2=0, the flow of power from the inverter to the load becomes zero.

Next, if the commercial power supply fails, the power will be transferred from the storage battery (4) to the inverter (3) to the second winding (6-) of the three-turn transformer (6),
11 2) - 3rd JllS line (6-3) - Load (7)? It is supplied in sequence without any momentary interruption. Further, in this case, the thyristor switch (5) is opened to prevent the flow of power from the inverter (3) to the commercial power source (1).

(8) is a resonant circuit that removes harmonics contained in the inverter output voltage and a variable inductor circuit that makes the output voltage constant; (9) is an automatic synchronization function and voltage This is a control circuit that has adjustment functions, alarm monitoring and display functions, etc.

Next, problems with the AC uninterruptible power supply shown in FIG. 1 will be described. In Figure 1, when the commercial power supply is normal and the inverter is in standby mode, if the commercial power supply fails, the output voltage that was operating with a delay of φ1 from the commercial power supply will now be delayed by φ2 from the inverter output. When the 3I#1 transformer starts operating, there is a new delay of φ2 compared to before the power outage, and this phase shift slows down the time change of the magnetic flux of the 3I#1 transformer, causing a transient fluctuation in which the output voltage decreases. FIGS. 3 and 4 show waveforms of various parts in that case. On the other hand, when the commercial power supply recovers from a power outage next time, transient fluctuations will occur in the output voltage due to a phase shift with the inverter depending on the input phase.

In the case of a commercial power outage, the present invention detects the power outage early and at the same time advances the phase of the inverter output by φ1 to bring the inverter output and the commercial power into the same phase. In this case, open the si-risk switch (5) until the inverter output is synchronized with the commercial power supply to prevent mutual interference due to phase shift between the commercial power supply and the inverter, and also to prevent the inverter phase from shifting to the AC output phase after synchronization. It is an object of the present invention to provide an AC uninterruptible power supply device in which the transient fluctuations are removed by gradually changing the phases.

FIG. 5 is a block diagram showing an embodiment of the control circuit according to the present invention, which will be described below.

Ql is a PT that detects the voltage waveform of the commercial power supply, (11) is a zero cross detector that detects the zero cross point of the commercial voltage signal, (12) is a synchronous oscillator that is triggered by the output of the zero cross detector (11), and (14) is a zero cross detector that detects the zero cross point of the commercial voltage signal. ) in zero cross detection! (11) is an exclusive OR circuit that compares the output waveform of the synchronous oscillator (12), (15) is an OR circuit,
(13) is a commercial power outage detector. (]9) is a sawtooth wave generator that converts the square wave output of the synchronous oscillator (12) into a sawtooth wave.

(17) is a phase-shifted voltage generator that receives the inverter input current signal SIN and generates a DC voltage EN corresponding to it, and another that generates a droop voltage E1 that brings the commercial power supply and the inverter output into phase. It is.

(18) is an analog switch that switches the phase shift voltage EN and El according to the signal from the commercial power failure detector (13), and its output becomes the reference voltage of the level regulator (19).

A level adjuster (19) adjusts the level of the sawtooth wave. (20) and (21) are comparators, which compare the reference voltage of the reference voltage generator (22) with the sawtooth wave to create a phase-shifted square wave and output it to the inverter driver (23).

Next, the operation of each part in the above configuration will be explained according to the time chart shown in FIG.

The commercial voltage signal (Figure 6(a)) is detected by the zero cross detector (1
1) and its output Q is the point where the sine wave changes from negative to positive,
Q becomes high level at the point where it changes from positive to negative (Fig. 6 (a), (bl, (C1)). Also, the synchronous oscillator (12) is triggered by the output of the zero cross detector (11) and the commercial voltage Generates a 60 Hz square wave synchronized with (Fig. 6(d), (81). Zero cross detector (
11) and the synchronous oscillator (12). The outputs are compared by the exclusive OR circuit (14), and if they are different, the output of the OR circuit (15) is shown in FIG.
It becomes high level at the timing shown in h) and instantaneously detects a commercial power outage.

The sawtooth wave generator (16) converts the square wave from the synchronous oscillator (Fig. 6(d), (81)) into a sawtooth wave and outputs it to the level adjuster (19).Level adjuster (19)
The level of the sawtooth wave is adjusted by the DC voltage EN or El from the phase-shifted voltage generator (17) which is switched by the analog switch (18) (FIG. 6(k)).

Comparators (20) and (21) generate level-adjusted sawtooth waves and reference voltages! (22) and outputs a phase-shifted square wave (FIG. 6 (1)) to the inverter driver (23) to drive the inverter.

The phase shift voltage EN is a phase shift voltage that receives the inverter input current signal SIN and makes the inverter output the same phase as the output of the three-turn transformer, and El is the phase shift voltage that makes the inverter output the same phase as the commercial power supply.

The level adjuster (19) is set to EN when the commercial power supply is normal.
The sawtooth wave is adjusted to the level shown in FIG. 6(k) by the phase shift voltage.

In addition, when the commercial power supply fails, the phase shift voltage switches from EN to El (Fig. 6 (J)) in response to the power failure signal (hl in Fig. 6), and as a result, the inverter output changes as shown in Fig. 6 (J). 1
) The output of the 3-turn transformer operates in the same phase as before the power outage during a commercial power outage due to the operation of 0 or more, which is instantaneously shifted to the same phase as the commercial power supply at the timing of ), so no transient fluctuation occurs in the output. In addition, when the power outage is restored, the drive signal (Fig. 6 (e)) of the silisk switch (5) is locked until the synchronous oscillator (12) is synchronized with the commercial power supply, and the commercial power supply (1) and the 3-turn transformer are locked. (6) and turns on the sirisk switch (5) when the inverter output and the commercial power supply are in the same phase, so there is no mutual interference between the inverter and the commercial power supply, and no transient fluctuation occurs in the output.

As described above, according to the present invention, the commercial power source and the inverter are input to the respective windings using a magnetic saturation type constant voltage transformer having a three-winding magnetic shunt, and the commercial power source is controlled by controlling the phase difference between the two. An AC uninterruptible power supply system that adjusts the flow of power from the inverter to zero while receiving power has a method that instantly detects a power outage in the commercial power supply and instantaneously advances the inverter phase at the same time. We have provided a means to turn on the commercial power when it detects that the power outage has been restored and the frequency phase of the commercial power source becomes the same phase as the inverter's phase, so even if the commercial power source fails while the inverter is in standby operation. Transient output fluctuations that occur when a power outage is restored can be removed by adding a small amount of control circuitry without the need for a large-scale filter, making it ideal for loads that require high-quality power sources such as computers. This has the effect of being able to eliminate the negative effects of

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of an AC uninterruptible power supply using a 3-turn transformer, Figure 2 is a circuit diagram explaining the flow of power using an idealized circuit of a 3-turn transformer, and Figure 3 is a commercial Figure 4 is a waveform diagram showing the waveforms and phase relationships of the commercial power supply voltage, inverter voltage, and output voltage when the power supply is normal; Figure 4 is a waveform diagram showing transient fluctuations in the output voltage when the commercial power supply is out of power; Figure 5 6 is a block diagram showing an embodiment of the present invention, and FIG. 6 is a time chart showing the operation of each part of the control circuit. (1) - Commercial power supply (2) - One charger (3) - M-Inverter + 41 - One storage battery (5) - - Cyrisk switch + 61 - Three-turn transformer (6-1) - (6 = 4 )-3-turn transformer winding (6-5)
--One iron core (6-6) --Magnetic shunt +71--One load (8)-m-Resonance circuit (91-One control circuit 0Φ-P T (11) --Zero cross detector (12)- -Synchronous oscillator (13)...Commercial power outage detector (4) -Exclusive OR circuit (15) -OR circuit (16) -Sawtooth wave generator (17) -Phase shift voltage Generator (18) ---Analog switch (19) --- Level adjuster (20), (21) --- Comparator (22) --
Reference voltage generator (23)... Inverter driver patent applicant Nishim Electronics Co., Ltd.'s agent Sunshi Ito (two idiots) Procedural amendment December zz, 1981 Commissioner of the Japan Patent Office Haruki Shimada-1, Display of the case 1982 Patent Application No. 11110731 3, Person making the amendment Relationship to the case Patent applicant address 4, agent 130-

Claims (1)

[Claims] 1. Using a magnetic saturation type constant voltage transformer with a 3* linear magnetic shunt, the commercial power source and the inverter are input to their respective windings, and the phase difference between the two is controlled so that while the commercial power source is being received, the In an AC uninterruptible power supply system that adjusts the flow of power to zero, there is a means for instantaneously detecting a power outage in the commercial power supply and instantaneously advancing the inverter phase at the same time, and a method for detecting a power outage in the commercial power supply after the power outage has been restored. An AC uninterruptible power supply system comprising means for detecting the frequency of the commercial power supply and turning on the commercial power supply when the phase of the frequency of the commercial power supply becomes the same phase as the phase of the inverter.