Abstract :
High power thyristors are employed with a battery to provide constant voltage to a quarter-megawatt dc load for 1/2 second, in order to operate a sonar transducer at a pulse repetition period of 10 seconds. Despite the heavy pulse power and the low duty cycle, the power drawn from the mains is maintained almost constant at approximately 12.5 kilowatts, with less than 5 percent variation over a power pulse cycle. The system utilizes a battery for energy storage, in conjunction with a phase-controled ac line to charge the battery at essentially constant current. The availability of high power thyristors for a high frequency inverter-type dc to dc converter makes the entire concept feasible, as the battery voltage drops substantially during the pulse. The inverter is pulse-width-controlled during the output power pulse, to maintain the dc output voltage constant within 3 percent during the power pulse. Basic circuits are described for providing the high peak power to the load, and maintaining virtually constant average power drain from the source over the entire cycle.
