Patents

Variable Speed AC Motor Control System (US 4,618,180)

Abstract

AC mains voltage input is directed to a bridge rectifier and converted to a DC voltage output. This DC power supplies an inverter which reconverts it to variable frequency AC output, used to drive a variable-speed AC motor.

A microprocessor-based control unit generates firing pulses for SCR's in both the rectifier and inverter. It maximizes the efficiency of the rectifier by generating phase delay and sequencing data in advance of each line-to-netural zero-crossover of the AC mains voltage input; it makes the voltage and frequency of the inverter AC output both proportional to the value of the DC voltage output, enabling the system to maintain a constant volts/Hertz ratio between the AC output voltage and the AC output frequency.

Appropriate fault protection circuits are included with the control unit to prevent fault conditions from damaging the system.

Ultra-Reliable Personnel Position Locating System (US 7,355,513 B1)

Abstract

A survivor locator system allows for the detection of the location for a person who is lost and requires recovery and extraction from their current environment. By using a phase matched antenna set, a GPS receiver, and a handheld simplified beacon-equipped survival transponder, an estimated distance and bearing data set can be retrieved. If this data set estimation is then fed through an error reduction filter, such as a Kalman filtering algorithm, continually refined location coordinates can be generated, leading the search and rescue crew members to the survivor. The survivor locator system and methods provide a handheld survival radio with reduced complexity.