Patents Assigned to Enova Systems
  • Patent number: 6538909
    Abstract: A universal power converter for generating a regulated voltage, current or power with a large input voltage range. The power converter has a voltage boost function configured to boost the rectified input voltage and provide power factor correction. The power converter also includes a voltage chop function to chop the boosted voltage to form an AC voltage. The power converter further includes at least one relay in electrical communication with the AC voltage and a transformer. The primary winding has at least two inputs operative to selectively vary the voltage generated on a secondary winding thereof selected by the relay. Accordingly, the power converter can generate different voltages at the output based upon the position of the relay and the boosted voltage. The power converter provides maximum power operation at a wide output voltage range, maximizing the charging energy.
    Type: Grant
    Filed: December 13, 2001
    Date of Patent: March 25, 2003
    Assignee: Enova Systems
    Inventors: Abas Goodarzi, Don Kang
  • Patent number: 6472880
    Abstract: A system for measuring voltages of batteries in a battery pack. The system has an isolation circuit operative to isolate a voltage for each of the batteries. A buffer of the system is in electrical communication with the isolation circuit and operative to store the voltage of each of the batteries when the batteries are isolated. The system further includes a voltage measuring device in electrical communication with the buffer. The voltage measuring device is operative to measure the voltage in the buffer and provide a stable measurement of the battery voltages therefrom.
    Type: Grant
    Filed: June 29, 2001
    Date of Patent: October 29, 2002
    Assignee: Enova Systems
    Inventor: Dennis H. Kang
  • Patent number: 6417670
    Abstract: A current measurement system for a battery is provided. The current measurement system has a shunt resistor in electrical communication with the battery. The shunt resistor is operative to generate a shunt voltage in response to the current flowing through the battery. The system further includes a voltage to frequency converter in electrical communication with the shunt resistor. The voltage to frequency converter is operative to generate a frequency signal in response to the shunt voltage. A processor of the system determines a frequency value from the frequency signal and determines the current of the battery from predetermined current values. In this respect, the processor can linearly interpolate the current through the battery from the value of the frequency signal and stored predetermined current values such that an accurate current measurement can be made.
    Type: Grant
    Filed: June 29, 2001
    Date of Patent: July 9, 2002
    Assignee: Enova Systems
    Inventor: Dennis K. Kang