초록 ▼

A control system that can accommodate the wide variations in the output of a generator, such as a permanent magnet alternator, while providing an output with relatively uniform phase ripple. The control system includes a zero crossing detector and variable ramp generator for generating control signa

A control system that can accommodate the wide variations in the output of a generator, such as a permanent magnet alternator, while providing an output with relatively uniform phase ripple. The control system includes a zero crossing detector and variable ramp generator for generating control signals to a switching rectifier to generate a regulated DC signal.

대표청구항 ▼

What is claimed is: 1. A system, responsive to at least one phase of an AC signal, for generating control signals to a switching rectifier to generate a regulated DC signal, the system comprising: a zero crossing detector, responsive to a first signal representative of the AC phase, for generating

What is claimed is: 1. A system, responsive to at least one phase of an AC signal, for generating control signals to a switching rectifier to generate a regulated DC signal, the system comprising: a zero crossing detector, responsive to a first signal representative of the AC phase, for generating indicia of zero crossings in the AC phase; a variable ramp generator, responsive to a second signal representative of the AC phase and the indicia of zero crossings, for generating a ramp signal indicative of the time integral of the voltage of the AC phase accumulated from the occurrence of a zero crossing and reset upon the occurrence of the next successive zero crossing; a trigger signal generator, responsive to the time integral ramp signal and a reference signal indicative of a desired firing angle to maintain a set DC output, for generating the control signals to the switching rectifier in accordance with a comparison of the time integral ramp signal to the reference signal. 2. The system of claim 1 wherein the first and second signals representative of the AC phase are different isolated signals. 3. The system of claim 1 wherein the first and second signals are representative of the AC phase are generated by respective secondary windings of an isolation transformer having a primary driven by the AC phase. 4. The system of claim 1 wherein the zero crossing detector comprises: a comparator, responsive to the first signal representative of the AC phase, for generating a signal indicative of the polarity of the AC phase signal, and transitions in the polarity signal indicating a zero-crossing; a variable blanker for generating a blanking pulse initiated in response to transitions in the polarity signal and having a duration equal to a predetermined portion of the period between successive zero crossings; and a reset pulse generator 216, for generating, in response to transitions of a predetermined polarity in the polarity signal, a pulse of predetermined duration as said indicia of zero crossings in the AC phase. 5. The system of claim 4 wherein the variable blanker comprises a one-shot having an associated timing capacitor, the pulse generated by the one-shot having a duration controlled by the time required to charge the timing capacitor, a current source disposed to charge the timing capacitor, the current source being driven by a signal proportional to the duty cycle of the one shot output so that the time required to charge the timing capacitor is inversely proportional to the duty cycle of the one shot output. 6. The system of claim 1, responsive to multiple phases of an AC signal, the system comprising for each phase: a zero crossing detector, responsive to a first signal representative of the AC phase, for generating indicia of zero crossings in the AC phase; a variable ramp generator, responsive to a second signal representative of the AC phase and the indicia of zero crossings, for generating a ramp signal indicative of the time integral of the voltage of the AC phase accumulated from the occurrence of a zero crossing and reset upon the occurrence of the next successive zero crossing; a trigger signal generator, responsive to the time integral ramp signal and a reference signal indicative of a desired firing angle to maintain a set DC output, for generating the control signals to the switching rectifier in accordance with a comparison of the time integral ramp signal to the reference signal. 7. The system of claim 6, responsive to a first phase of the AC signal, and at least one other phase, further including for each other phase a respective AGC Amp to compare the average voltage of the ramp from the ramp generator associated with the first phase with the average voltage of the ramp from the ramp generator associated with such other phase and adjusts the gain of the ramp generator associated with such other phase so that the time integral of the ramp from the ramp generator associated with such other phase is equal to the time integral of the ramp from the ramp generator associated with the first phase.