Clamped quasi-resonant step-up inverter
A device which, through its self-oscillation, generates a stable high voltage DC or AC output from a low voltage DC input. The device automatically maintains a desired voltage on an output capacitor, despite changes in output load or input voltage. The device is capable of dead-short operation, capacitor charging, high voltage step-up, high efficiency, and high power density. The capability to step up low voltage to high voltage in such a manner paves the way for advancement in battery-to-grid inverter technology, portable welding devices, portable medical devices, aircraft and spacecraft propulsion devices among many other areas.
1. An apparatus which accepts an input electrical power having an input voltage and an input current and produces an output electrical power, comprising:
a) a transformer having a primary side and a secondary side wherein the primary side is connected to the input electrical power and comprises at least three taps; a first terminal tap RPM, a second terminal tap, and a center tap;
b) the primary side of the transformer being configured to be switched by an oscillating mechanism with a frequency that is positively correlated with the input voltage;
c) the secondary side of the transformer coupled magnetically with and electrically insulated from the primary side;
d) one pole of a decoupling capacitor connected to the secondary side of the transformer;
e) a rectifier connected to the opposing pole of the decoupling capacitor, and;
f) a first pole of a load capacitor connected to the rectifier and the output electrical power, and a second pole of the load capacitor connected to ground, wherein the load capacitor's voltage correlated with a known reference is fed back into the oscillating mechanism in order to maintain a stable output voltage independent of the input voltage of the input electrical power,
wherein the oscillating mechanism comprises one or more switches which are placed between each of the first and second terminal taps on the primary side of the transformer and to ground, and whereby control signals of at least one switch connected to the first terminal tap are electrically coupled to switched paths of at least one switch connected to the second terminal tap; and
g) one or more diodes, each having an anode and a cathode, which are placed between the at least one switch connected to the first terminal tap and the at least one switch connected to the second terminal tap; and
h) at least one tank capacitor placed between the cathodes of the one or more diodes.
2. The apparatus of claim 1 , wherein the decoupling capacitor is non-polarized.
3. The apparatus of claim 1 , further comprising an inductor with an inductance level between 1-500 μH connected to the center tap on the primary side of the transformer.
4. The apparatus of claim 1 , wherein the transformer is designed to operate at a frequency between 1-750 kHz.
5. The apparatus of claim 1 , wherein the one or more diodes are of standard P-N type, or of type Schottky, Zener, Tunnel, Step, PIN, LED or Varactor.
6. The apparatus of claim 1 , wherein the at least one tank capacitor is made of multi-layer ceramic, mica, single layer ceramic, PTFE, metallized film, oil-filled, tantalum, or electrolytic material.
7. The apparatus of claim 6 , wherein the at least one tank capacitor has a capacitance value which is strongly dependent upon applied voltage.
8. The apparatus of claim 1 , wherein the decoupling capacitor has a capacitance value between 0.1-1000 nF.
9. The apparatus of claim 1 , wherein the rectifier is a full wave type.
10. The apparatus of claim 3 wherein the inductor possesses a saturation current rating at least twice that of the transformer.
11. The apparatus of claim 9 , wherein the ground is shared between the rectifier on the secondary side of the transformer and the ground on the primary side of the transformer.
12. The apparatus of claim 9 , wherein the rectifier utilizes series of diodes which are of standard P-N type or type Schottky, avalanche, Zener, tunnel, step, PIN, freewheel, or varactor.
13. The apparatus of claim 12 wherein the series of diodes are capable of ultra-fast switching with a reverse recovery time of less than 100 ns.