Technologies for converter topologies
View Patent ↗In some embodiments of the disclosed inverter topologies, an inverter may include a full bridge LLC resonant converter, a first boost converter, and a second boost converter. In such embodiments, the first and second boost converters operate in an interleaved manner. In other disclosed embodiments, the inverter may include a half-bridge inverter circuit, a resonant circuit, a capacitor divider circuit, and a transformer.
1. An inverter for converting an input direct current (DC) waveform from a DC source to an output alternating current (AC) waveform for delivery to an AC grid, the inverter comprising:
an input converter electrically coupled to a DC power bus, wherein the input converter is configured to convert the input DC waveform to a bus waveform supplied to the DC power bus and comprises:
a full bridge resonant converter including (i) a first electrical switch and a second electrical switch electrically coupled to each other at a first electrical connection, and (ii) a third electrical switch and a fourth electrical switch electrically coupled to each other at a second electrical connection, and (iii) a resonant tank circuit electrically coupled to the first electrical connection;
a first boost converter that includes (i) a capacitor, (ii) the first electrical switch and the second electrical switch, and (iii) a first inductor having a first terminal to receive the input DC waveform and a second terminal electrically coupled to the first electrical connection; and
a second boost converter that includes (i) the capacitor, (ii) the third electrical switch and the fourth electrical switch, and (iii) a second inductor having a first terminal electrically coupled to the first terminal of the first inductor to receive the input DC waveform and a second terminal electrically coupled to the second electrical connection,
wherein the first electrical switch and the third electrical switch are electrically coupled to the capacitor at a third electrical connection; and
wherein the second electrical switch and the fourth electrical switch are electrically coupled to the capacitor at a fourth electrical connection.
2. The inverter of claim 1 , wherein the capacitor comprises (i) a first terminal electrically coupled to the first electrical switch and the third electrical switch at a fifth electrical connection and (ii) a second terminal electrically coupled to the second electrical switch and the fourth electrical switch at a sixth electrical connection.
3. The inverter of claim 1 , wherein the resonant tank circuit includes a resonant capacitor and a resonant inductor electrically coupled in series.
4. The inverter of claim 3 , wherein the full bridge resonant converter further comprises a transformer and the resonant inductor comprises a resonant inductance formed from at least one of a leakage inductance and a magnetizing inductance of the transformer.
5. The inverter of claim 3 , wherein the resonant capacitor resonates with the leakage inductance and energy is transferred from the capacitor across the transformer during resonance in response to one of (i) the first electrical switch and the third electrical switch being active or (ii) the second electrical switch and the fourth electrical switch being active.
6. The inverter of claim 1 , wherein each of the first boost converter and the second boost converter is configured to increase a magnitude of the input DC waveform to generate a boosted DC waveform.
7. The inverter of claim 6 , wherein:
the first and second electrical switches and the third and fourth electrical switches of the full bridge resonant converter are configured to receive the boosted DC waveform and to generate a square waveform; and
the resonant tank circuit is configured to receive the square waveform and to convert the square waveform to a resonant sinusoidal waveform.
8. The inverter of claim 1 , further comprising an inverter controller electrically coupled to the input converter and configured to control operation of the first and second electrical switches and the third and fourth electrical switches.
9. The inverter of claim 8 , wherein the inverter controller is configured to operate the first and second electrical switches with a phase shift relative to the third and fourth electrical switches for interleaved operation of the first and second boost converters.
10. The inverter of claim 8 , wherein at least one electrical switch of the first and second electrical switches or third and fourth electrical switches is controlled by the inverter controller using zero-voltage switching.
11. The inverter of claim 8 , wherein the inverter controller is configured to control operation of the first and second electrical switches and the third and fourth electrical switches using pulse width modulation and duty cycle modifications.
12. The inverter of claim 8 , wherein at least one of the first boost converter and the second boost converter is configured to operate at a fixed frequency; and
wherein the corresponding electrical switches are controlled via pulse-width modulation duty cycle control.
13. The inverter of claim 1 , wherein the full bridge resonant converter further comprises a transformer, and further comprising:
a rectifier circuit electrically coupled to a secondary winding of the transformer and to the DC power bus, wherein the rectifier circuit is configured to convert an input AC waveform received from the secondary winding of the transformer to the bus waveform supplied to the DC power bus.
14. The inverter of claim 1 , wherein the DC source is embodied as a photovoltaic power source.