Abstract: A discharge lighting system includes a lighting server responsive to input power for controlling the operation of discharge lamps. An inverter in the server includes a full switching bridge having a first leg and a second leg operable at a common switching frequency but out of phase to provide for pulse width modulation and frequency variations to dim the discharge lamps. A protection circuit is provided to reduce the circulating currents resulting from an open-circuit condition. A power factor circuit includes an output capacitor which is maintained fully charged while the switching circuits are de-energized to extinguish the lamps. The charged condition of the capacitor avoids high in-rush currents when the lamps are again illuminated by activation of the switching circuit. A first tank circuit included in the inverter has a first resonant frequency which is greater than the switching frequency of the switching members.

Abstract: An electrical power controller includes a boost converter, an invertor and an output section. The boost converter includes a control circuit which charges a capacitance from an inductance in accordance with a stream of pulses having a variable duty cycle. A feedback circuit responsive to the power consumed by a load provides an error signal for varying the duty cycle of the pulses. In the invertor, a pair of switches sample the charge on the capacitor to create an AC signal which is introduced to the output section. The sampling frequency in the boost converter is related to the sampling frequency in the invertor by an integer.

Abstract: A method of extending discharge lamp life includes slowing electrode deterioration by powering the discharge lamp so that a lamp arc current having a reduced crest factor results, either by retrofitting an existing discharge lamp system with a waveform conditioning module, by powering the discharge lamp with a ballast producing a squarewave-type waveform, or by slowing deterioration of an emissive coating on a discharge lamp electrode by such means as preheating the electrode prior to use in order to bond the emissive coating on the electrode. A discharge lamp system includes a discharge lamp and components operatively coupled to the discharge lamp for supplying a lamp arc current to the discharge lamp that has a reduced crest factor and controlled lamp watt loading, such as a ballast configured to supply a lamp arc current with a waveform that is substantially a squarewave or an existing ballast retrofitted with waveform conditioning circuitry that causes the lamp arc current to have a reduced crest factor.