Very high efficiency, high power VLF/LF amplifier
Abstract
A four-element full bridge voltage driven inverter has been developed and produced for use in VLF/LF airborne communications transmitters (27-60 kHz frequency range). Power transformers are eliminated and power supply complexity is minimized by the use of a very high efficiency voltage fed bridge inverter circuit which operates from an unregulated power supply direct rectified from the 3 phase, 400-Hz source. The amplifier delivers more than 25 kW continuous power at 97 percent dc to RF efficiency. The inverter utilizes four bipolar transistors in each leg of the full bridge, and it includes circuitry to return the out-of-phase currents to the dc supply. An improved drive technique prevents simultaneous conduction (shoot-thru) of the two active devices in series across the dc supply; and driver complexity is minimized by the use of simple 180-deg square wave switching.
- Publication:
-
PESC 1983; 14th Annual Power Electronics Specialists Conference
- Pub Date:
- 1983
- Bibcode:
- 1983ppes.conf..226K
- Keywords:
-
- Electric Bridges;
- Electric Power Supplies;
- Network Synthesis;
- Power Amplifiers;
- Power Efficiency;
- Static Inverters;
- Aircraft Communication;
- Bipolar Transistors;
- Low Frequencies;
- Power Supply Circuits;
- Square Waves;
- Switching Circuits;
- Transistor Circuits;
- Very Low Frequencies;
- Waveforms;
- Electronics and Electrical Engineering