Synchronized array bridge power oscillator
View Patent ↗An electronic high frequency induction heater driver, for a variable spray fuel injection system, uses a scalable array of zero-voltage switching oscillators that utilize full and half-bridge topology wherein the semiconductor switches are synchronous within each bridge for function, and each bridge is synchronized for function along the entire array. The induction heater driver, upon receipt of a turn-on signal, multiplies a supply voltage through a self-oscillating series resonance, wherein one component of each tank resonator circuit comprises an induction heater coil magnetically coupled to an appropriate loss component so that fuel inside a fuel component is heated to a desired temperature.
1. A synchronized array bridge power oscillator for an electronic induction heater driver, the synchronized array bridge power oscillator comprising:
an H-bridge circuit comprising high-side and low-side semiconductor switches and a resonant tank circuit comprising a tank circuit inductor and tank circuit capacitor, the resonant tank circuit being electrically connected between legs of the H-bridge circuit, the tank circuit inductor configured to be able to inductively heat a fuel injector;
a plurality of half-bridge circuits, each half-bridge circuit comprising high-side and low-side semiconductor switches and a corresponding tank circuit, the plurality of half-bridge circuits being connected in parallel to the H-bridge circuit and connected in parallel to each other, adjacent pairs of half-bridge circuits forming a virtual H-bridge circuit, which is synchronized with the H-bridge circuit;
a plurality of induction heater coils, each induction heater coil being coupled to a corresponding one of the plurality of half-bridge circuits and configured to inductively heat a corresponding fuel injector;
at least one energy replenishment inductor coupled to the resonant tank circuit and to the each of the plurality of half-bridge circuits, the energy replenishment inductor configured to supply energy to the resonant tank circuit and the plurality of half-bridge circuits;
wherein the H-bridge circuit, the half-bridge circuits, and energy replenishment inductor are configured to provide current to a first end of the tank circuit inductor and first end of the induction heater coils during a first half of a sine wave and provide current to an opposite second end of the tank circuit and opposite ends of the induction heater coils during a second half of the sine wave; and
wherein half-bridge switch timing is determined by a synchronized frequency of resonant tank circuits in the H-bridge circuit and the half-bridge circuits.
2. The synchronized array bridge power oscillator of claim 1 , wherein the energy replenishment inductor is between a voltage source and the high-side switches to source current to the resonant tank circuit from the voltage source.
3. The synchronized array bridge power oscillator of claim 2 , wherein the energy replenishment inductor is between a voltage sink and the low-side switches to sink current from the resonant tank circuit to an absolute voltage sink that is less than the voltage source.
4. The synchronized array bridge power oscillator of claim 1 , wherein H-bridge synchronization is accomplished through rectifier diodes sinking charge from one leg of a bridge circuit to an opposite leg of a bridge.
5. The synchronized array bridge power oscillator of claim 1 , wherein the bridge synchronization is accomplished through resistors sourcing charge from a voltage supply.
6. The synchronized array bridge power oscillator of claim 1 , wherein an inductance of the energy replenishment inductor is greater than an inductance of each of the plurality of the induction heater coils.
7. The synchronized array bridge power oscillator of claim 1 , wherein an inductance of the energy replenishment inductor is more than twice an inductance value of each of the plurality of the induction heater coils.
8. The synchronized array bridge power oscillator of claim 1 , wherein the H-bridge circuit and energy replenishment inductor are configured to provide current to the first end of the tank circuit inductor during a first half of sine wave and provide current to the second end of the tank circuit during a second half of the sine wave, the first and second sine waves being defined by the sine wave polarity.
9. The synchronized array bridge power oscillator of claim 1 , wherein the tank circuit inductor and a tank circuit capacitor are connected in parallel to each other.
10. The synchronized array bridge power oscillator of claim 1 , wherein the tank circuit inductor is a single coil and wherein each coil of the plurality of induction heater coils are single coils, each coil being configured to provide induction heating for a corresponding fuel injector.