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US 7,176,658 B2Granted
Controller for permanent magnet alternator
AssigneeMagnetic Applications, Inc.
InventorsFazle Quazi, Harold C. Scott, Stewart C. Koch
Life of this patent
Estimating the term…
Abstract
The invention is a control system that, among other things, controls a permanent magnet alternator and provides relatively accurate voltage regulation. The control system may include one or more of the following: (1) a rectification system to rectify and regulate the output voltage of an alternator, (2) a rectifier/limiter used as an electrical power source to a boost type regulator, (3) a multimode rectifier/limiter, (4) a DC to AC inverter bridge, and (5) power switches employed in the system to minimize the switching energy that would otherwise be dissipated in the power switches as heat.
Claims30
A system responsive to an alternating current input signal of relatively high maximum level varying voltage, for generating a regulated DC output signal having a predetermined output voltage, the system comprising:
- a rectifier for generating, from the input signal, a rectified DC signal having a predetermined initial maximum voltage, said initial maximum voltage being a high voltage relative to said predetermined output voltage;
- a regulator for generating, from the rectified DC signal, a regulated DC signal at a predetermined intermediate voltage, the predetermined intermediate voltage being a high voltage relative to said predetermined output voltage;
- and
- at least one DC to DC converter for generating, from the regulated higher voltage DC signal, the regulated DC output signal having said predetermined output voltage, the DC to DC converter including at least one switching element that tends to be subject to turn off losses, and further includes a capacitor disposed to limit the rate of change of voltage across the switching element during turn off, and a circuit for selectively discharging the capacitor to the output of the regulator, such that the capacitor is substantially fully discharged by the beginning of the next successive turn-off period,
- the circuit for selectively discharging the capacitor comprising an inductor, a second switching device, and a diode, the second switching device being connected in series with the inductor across the capacitor, with the diode disposed to provide a directional current path between the inductor and the output of the rectifier.
2 more elements
A system responsive to an alternating current input signal of relatively high maximum level varying voltage, for generating a regulated DC output signal having a predetermined output voltage, the system comprising:
- a rectifier for generating, from the input signal, a rectified DC signal having a predetermined initial maximum voltage, said initial maximum voltage being a high voltage relative to said predetermined output voltage;
- a regulator for generating, from the rectified DC signal, a regulated DC signal at a predetermined intermediate voltage, the predetermined intermediate voltage being a high voltage relative to said predetermined output voltage;
- and
- at least one DC to DC converter for generating, from the regulated higher voltage DC signal, the regulated DC output signal having said predetermined output voltage,
- wherein at least one of the rectifier and regulator includes at least one power switching element that tends to be subject to turn off losses, and further includes first and second diodes, a capacitor, an inductor, and a switching device, with the first diode and capacitor connected across the power switching element, the switching device connected in series with the inductor across the capacitor, and the second diode disposed to provide a directional current path between the inductor and a predetermined discharge point.
2 more elements
A system responsive to an alternating current input signal of relatively high maximum level varying voltage, for generating a regulated DC output signal having a predetermined output voltage, the system comprising:
- a rectifier for generating, from the input signal, a rectified DC signal having a predetermined initial maximum voltage, said initial maximum voltage being a high voltage relative to said predetermined output voltage;
- a regulator for generating, from the rectified DC signal, a regulated DC signal at a predetermined intermediate voltage, the predetermined intermediate voltage being a high voltage relative to said predetermined output voltage;
- and
- at least one DC to DC converter for generating, from the regulated higher voltage DC signal, the regulated DC output signal having said predetermined output voltage;
- the rectifier comprising a multi-mode circuit which alternatively operates in full wave rectification or half wave rectification modes, in accordance with the instantaneous voltage of the input signal,
- switching from full wave rectification to half wave rectification when the input signal voltage reaches said initial maximum voltage;
- and
- switching from half wave rectification to full wave rectification when the input signal voltage drops below a predetermined lower threshold value, the predetermined lower threshold value being less than said initial maximum voltage by a predetermined difference;
- and
- when in the half wave rectification mode, alternatively operates in full duty cycle or pulse width modulated modes in accordance with the voltage of the rectified DC signal, switching to pulse width modulated mode when the voltage of the rectified DC signal would otherwise exceed said initial maximum voltage.
7 more elements
A system responsive to an alternating current input signal of relatively high maximum level varying voltage, for generating a regulated DC output signal having a predetermined output voltage, the system comprising:
- a rectifier for generating, from the input signal, a rectified DC signal having a predetermined initial maximum voltage, said initial maximum voltage being a high voltage relative to said predetermined output voltage;
- a regulator for generating, from the rectified DC signal, a regulated DC signal at a predetermined intermediate voltage, the predetermined intermediate voltage being a high voltage relative to said predetermined output voltage;
- and
- at least one DC to DC converter for generating, from the regulated higher voltage DC signal, the regulated DC output signal having said predetermined output voltage;
- the rectifier comprising a multi-mode circuit which alternatively operates in full wave rectification or half wave rectification modes, in accordance with the instantaneous voltage of the input signal, and, when in the half cycle mode, alternatively operates in full duty cycle or pulse width modulated modes in accordance with the voltage of the rectified DC signal;
- the multi-mode circuit:
- switching from full wave rectification to half wave rectification when the input signal voltage reaches said initial maximum voltage;
- switching from half wave rectification to full wave rectification when the input signal voltage drops below a predetermined lower threshold value, the predetermined lower threshold value being less than said initial maximum voltage by a predetermined difference;
- dithering between full wave and half wave rectification under conditions where full wave rectification generates output levels in excess of said initial maximum voltage, but half wave rectification does not provide output levels at least equal to the predetermined lower threshold value;
- and
- when in the half wave rectification mode switching to pulse width modulated mode when the voltage of the rectified DC signal would otherwise exceed said initial maximum voltage.
8 more elements
A system responsive to an alternating current input signal of relatively high maximum level varying voltage, for generating a regulated DC output signal having a predetermined output voltage, the system comprising:
- a rectifier for generating, from the input signal, a rectified DC signal having a predetermined initial maximum voltage, said initial maximum voltage being a high voltage relative to said predetermined output voltage;
- the rectifier comprising
- a rectifier bridge circuit for, responsive to control signals applied thereto, selectively effecting full wave rectification of the input signal;
- a half bridge conversion circuit cooperating with the rectifier bridge circuit, for, responsive to control signals applied thereto, selectively effecting half wave rectification of the input signal;
- a pulse width modulator for, responsive to indicia of the output signal voltage, selectively controlling the duty cycle of the half wave rectified signal, and
- a control circuit, responsive to indicia of the input signal, for generating said control signals to the rectifier bridge circuit and half bridge conversion circuit;
- a regulator for generating, from the rectified DC signal, a regulated DC signal at a predetermined intermediate voltage, the predetermined intermediate voltage being a high voltage relative to said predetermined output voltage;
- and
- at least one DC to DC converter for generating, from the regulated higher voltage DC signal, the regulated DC output signal having said predetermined output voltage.
6 more elements
Dependencies are inferred from the claim text.