Apparatus for parallel operation of triport uninterruptable power source devices

• US 5,237,208 A
• Filed: 10/07/1991
• Issued: 08/17/1993
• Est. Priority Date: 10/25/1988
• Status: Expired due to Fees

• Current Assignee: Nishimu Electronics Industries Co. Ltd. (Kyushu Electric Power Company Incorporated)
• Original Assignee: Nishimu Electronics Industries Co. Ltd. (Kyushu Electric Power Company Incorporated)
• Inventors: Kawata, Yasuhiro, Koike, Hidehiro, Tominaga, Fukutoshi
• Primary Examiner(s): Pellinen, A. D.
• Assistant Examiner(s): Fleming, Fritz M.
• Application Number:
  US07/772,596
• Time in Patent Office: 680 Days
• Field of Search: 307/43, 307/52, 307/53, 307/57, 307/58, 307/64-66, 307/82-87, 323/307
• US Class Current: 307/66
• CPC Class Codes: G05F 1/59 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: G05F 1/62 using bucking or boosting dc sources
• CPC Class Codes: H02J 9/062 for AC powered loads

Abstract

In an apparatus for parallel operation of plural uninterruptable power source devices, each power source device includes at least one of an operation mode monitor for a logic operation on the output of the AC input monitoring circuit of each of the uninterruptable power source devices to feed the result thereof as a mode controlling signal to the mode controller, a parallel synchronizing signal generator for a logic operation on the output of an oscillating circuit which drives the invertor in each of the uninterruptable power source devices and, on detection of abnormality in the AC input, feeds the result thereof as a trigger pulse to the oscillating circuit, and a synchronization monitor for a logic operation on the output from the oscillating circuit in each of the uninterruptable power source devices and, when the differences between the phase of the output from the oscillating circuit of one of the triport uninterruptable power source devices and that from the oscillating circuits of remaining triport uninterruptable power source devices exceed the prescribed level, issuing a parallel operation release signal to open the switch of said one triport uninterruptable power source device that permits it to operate in parallel.

Claims

1. An apparatus for the parallel operation of triport uninterruptable power source devices which are adapted to be connected in parallel between an AC input power source and an output terminal so as to be operable in parallel therebetween, said apparatus comprising:

a plurality of triport uninterruptable power source devices each comprising;

a three-winding transformer having a first, a second and a third winding;

an AC input suited for connection to an AC input power source and connected to the first winding of the transformer through a first inductive component;

an inverter connected to the second winding of the transformer through a second inductive component;

an output terminal connected to the third winding of the transformer through a parallelization switch;

means for driving the inverter in synchronization with the voltage waveform of the AC input power source if connected to the AC input including an oscillating circuit adapted to be selectively triggered by pulses corresponding to the zero crossing points of the AC input power source voltage waveform so that such pulse triggering thereof results in an oscillating circuit output waveform with a corresponding phase, a phase shifter for providing phase shifting of the output waveform produced by the oscillating circuit, and an inverter driver for supplying the inverter with the output of the phase shifter;

an AC input monitoring circuit for detecting AC input power source voltage waveform abnormality if present on the AC input and providing an output signal indicating whether such an abnormality has occurred;

a mode controlling means for executing a logic operation on the output signal of the AC input monitoring circuit to switch the operation mode of the inverter between a standby mode, absent any abnormality being detected by the AC input monitoring circuit in which mode substantially no output current is generated by the inverter, and an inverter mode, upon the occurrence of an abnormality being detected in the AC input monitoring circuit in which mode an output current is generated by the inverter; and

a synchronization monitoring means for comparing phases of the output waveforms of the oscillating circuits in the plurality of triport uninterruptable power source devices such that, if any differences between the phase of the output from the oscillating circuit of one of the triport uninterruptable power source devices and the phases of the outputs from the oscillating circuits of the remaining ones of the plurality of triport uninterruptable power source devices exceeds a selected level, the synchronizing monitoring means for that triport uninterruptable power source device provides a parallel operation release signal to open the parallelization switch thereof.

2. An apparatus according to claim 1, wherein at least one of the first and second inductive component is a leakage inductance generated by the magnetic shunt formed on a magnetically permeable core of the three-winding transformer.

3. An apparatus according to claim 1, wherein at least one of the first and second inductive component is an inductor connected in series to the corresponding input winding of the three-winding transformer.

4. An apparatus according to claim 1, wherein the magnitudes of the first and second inductive components of each of the triport uninterruptable power source devices are set so as to be inversely proportional to the respective output capacities.

5. An apparatus according to claim 1, wherein the magnetically permeable core of the three-winding transformer is divided with two magnetic shunts into three sections including one central and two terminal sections and the third winding is formed on one terminal section and the first and the second windings are formed in the remaining two sections.

6. An apparatus according to claim 1, wherein the output terminal has a voltage stabilizer connected thereto.

7. An apparatus according to claim 1, wherein the triport uninterruptable power source device is for the three-phase configuration and the three transformers are arranged substantially along the edges of a triangular prism in such a manner that the rectangular magnetically permeable cores of any two adjacent transformers will be disposed parallelly to each other to form three paired legs and a common winding is formed on each of the paired legs.

8. The apparatus according to claim 1 wherein at least one of the plurality of input uninterruptable power source devices further comprises an operation mode monitoring means for performing a logic operation on the output signals of the AC input monitoring circuits of the plurality of triport uninterruptable power source devices and providing a result of the logic operation as a mode controlling signal to the mode controlling means of each of the plurality of triport uninterruptable power source devices.

9. The apparatus according to claim 1, wherein at least one of the plurality of triport uninterruptable power source devices further comprises a parallel synchronizing signal generating means for executing a logic operation on the output waveforms of the oscillating circuits of the plurality of triport uninterruptable power source devices and, on detection of an abnormality by the corresponding AC input monitoring circuits, providing the results of the logic operation as trigger pulses to the oscillating circuits of each of the plurality of triport uninterruptable power source devices.

10. The apparatus according to claim 1 wherein each of said plurality of triport uninterruptable power sources has therein an operation mode monitoring means and a parallel synchronizing signal generating means, and with the operation mode monitoring means performing a logic operation on output signals of the AC input monitoring circuits of the plurality of triport uninterruptable power source devices and providing a result of the logic operation as a mode controlling signal to the mode controlling means of the triport uninterruptable power source device corresponding thereto, and with the parallel synchronizing signal generating means performing a logic operation on the output waveforms of the oscillating circuits of the plurality triport uninterruptable power sources and, on detection of an abnormality by the corresponding AC input monitoring circuit, providing the results of the logic operation as trigger pulses to the oscillating circuit of the triport uninterruptable power source device corresponding thereto.

11. The apparatus according to claim 8, wherein the operation mode monitoring means further uses a result of the logic operation therein to provide a parallel operation release signal to open the parallelization switch for that triport uninterruptable power source device corresponding thereto if the output signal from the corresponding AC input monitoring circuit differs from the output signals from the AC input monitoring circuits of the remaining ones of the plurality of triport uninterruptable power source devices.