High frequency series AC voltage regulator
A bidirectional AC series voltage regulator that regulates an output AC voltage level regardless of the varying AC input voltage utilizing high frequency series inductors that only process a proportion of the total output power. The AC series voltage regulator detects the power inductor current direction data signal and can generate power inductor current direction data signals for its control to determine the AC input voltage polarity at all time; wherein the determination of the AC input voltage polarity is unambiguous during the AC input voltage zero crossover and near zero points; and wherein the determination of the AC input voltage polarity allows normal switching sequence of the AC bidirectional switches during the AC input voltage zero crossover and near zero points to prevent power “shoot-through.”
1. An alternate current (AC) series voltage regulator for regulating an AC output voltage of an AC output power source, comprising:
an AC high frequency (HF) series voltage buck power regulator topology for bucking an AC input voltage of an AC input power source, comprising:
a first and a second independently controllable AC bidirectional switches,
a first power inductor, and
a first current transformer for generating a first power inductor current direction data signal indicating the first power inductor current direction;
an AC HF series voltage boost power regulator topology for boosting the AC input voltage, comprising:
a third and a forth independently controllable AC bidirectional switches,
a second power inductor, and
a second current transformer for generating a second power inductor current direction data signal indicating the second power inductor current direction; and
a control circuitry for receiving the AC input voltage, an AC reference voltage, the AC output voltage, the first power inductor current direction data signal, and the second power inductor current direction data signal, and generating switch driving signals for the AC bidirectional switches.
2. The AC series voltage regulator of claim 1 , wherein the AC HF series voltage buck power regulator topology being activated and operating, and wherein the AC HF series voltage boosting power regulator topology being inactivated.
3. The AC series voltage regulator of claim 1 , wherein the AC HF series voltage boost power regulator topology being activated and operating, and wherein the AC HF series voltage bucking power regulator topology being inactivated.
4. The AC series voltage regulator of claim 1 , further comprising an input filter for eliminating HF switching energy from passing back into the AC input power source.
5. The AC series voltage regulator of claim 4 , wherein the input filter comprising two capacitors and two inductors.
6. The AC series voltage regulator of claim 1 , further comprising an output filter for averaging HF voltage ripple to create a smooth regulated voltage level for the AC output voltage.
7. The AC series voltage regulator of claim 6 , wherein the output filter comprising two capacitors and two inductors.
8. The AC series voltage regulator of claim 1 , further comprising a third current transformer for generating an output current measurement signal to the control circuitry to achieve over-current protection.
9. The AC series voltage regulator of claim 1 , wherein the switch driving signals for the AC bidirectional switches being pulse width modulation (PWM) control signals.
10. The AC series voltage regulator of claim 1 , wherein each of AC bidirectional switches comprising one or more power semiconductor devices.
11. The AC series voltage regulator of claim 10 , wherein the power semiconductor devices being back-to-back unipolar MOSFET power semiconductor devices, silicon-controlled rectifiers (SCR)'s, gate turn off thyristor (GTO)'s connected as anti-parallel AC switches, TRIAC's, insulated-gate bipolar transistors (IGBT)'s, MOSFET transistors, or SCR's configured as AC switches.
12. The AC series voltage regulator of claim 1 ,
wherein the control circuitry uses the AC input voltage polarity, and either one or both of the first power inductor current direction data signal and the second power inductor current direction data signal for a determination of a switching sequence of the AC bidirectional switches;
wherein the switching sequence of the AC bidirectional switches determined is unambiguous; and
wherein the determination of the unambiguous switching sequence of the AC bidirectional switches eliminates any necessity of any power “shoot-through” in the switching sequence.