An electric power converting device is provided which supplies a constant voltage to a load (6) while suppressing voltage variation in an ac power source (1). The breakdown voltages of semiconductor switching elements are reduced for reducing duties and co...

The un-interrupted power supply has transformer and rectifier system for supplying electrical energy to the network (4) in the format required of the network. The conversion circuits are reversible, so that when supply is available, the battery may be rech...

A local power generation system generates a substantially DC inverter input voltage, which is modulated to generate a resulting output AC power signal to a load. The inverter input voltage may be obtained from an engine generator, providing an AC power sig...

An uninterruptible power supply is provided that is capable of turning off an AC switch made up of thyristors as quickly as possible by using a power converter. A power is supplied from the utility power supply 3 to the load 9 through the AC switch 1 made ...

An uninterruptible power system capable of reducing strain in an output voltage thereof as compared with the prior art. A DC voltage control circuit of a current control system obtains an input current command value on the basis of a multiplied value betwe...

A method and apparatus are disclosed for improving the disturbance pass through characteristics of a line interactive uninterruptible power supply ("UPS"). One disclosed technique uses a naturally commutated fast utility disconnect switch, wherein the swit...

A drive apparatus for a vibrating-type compressor, comprising a DC power source; an inverter including switching elements and adapted to convert direct current to alternating current through alternating switching of the switching elements; and an inverter ...