Highly efficient isolated bidirectional DC/AC topologies
View Patent ↗Method and apparatus include a first stage converter configured to generate a half sine wave, and a second stage converter in electrical communication with the first stage converter and configured to transform the half sine wave into a power signal. The second stage converter may further supply the power signal to an electrical grid. In one example, the second stage converter may include an isolated, unregulated, resonant direct current/alternating current (DC/AC) converter.
1 . An apparatus comprising:
a bidirectional direct current (DC)/alternating current (AC) circuit having a 1.5 stage topology comprising:
a whole stage converter comprising a half bridge inverter configured to transform a DC voltage to an always positive half sine wave having a first voltage, wherein when operating in a soft switching mode, a switching speed of the half bridge inverter increases without degrading an efficiency of the half bridge inverter; and
a half stage converter in electrical communication with the whole stage converter, the half stage converter-having a fixed-gain, the half stage converter comprising a half bridge inverter configured to transform the always positive half sine wave having the first voltage to an always positive half sine wave having a second voltage that is higher than the first voltage, the half stage converter further comprising an unfolding bridge inverter configured to transform the always positive half sine wave having the second voltage into an AC power signal, and to supply the AC power signal to an electrical grid.
2 . The apparatus of claim 1 , wherein the whole stage converter is non-isolated.
3 . The apparatus of claim 1 , wherein the half stage converter is isolated.
4 . The apparatus of claim 1 , wherein the half stage converter is unregulated.
5 . The apparatus of claim 1 , wherein the whole stage converter is regulated.
6 . The apparatus of claim 1 , wherein the half stage converter is a direct current/alternating current (DC/AC) converter.
7 . The apparatus of claim 1 , wherein the AC power signal includes a full sine wave.
8 . The apparatus of claim 1 , wherein a voltage link is positioned in between the whole stage converter and the half stage converter.
9 . The apparatus of claim 1 , wherein the whole stage converter is one of a plurality of whole stage converters wired in parallel and in electrical communication with the half stage converter.
10 . The apparatus of claim 1 , wherein the half stage converter further comprises a transformer coupled between the half bridge inverter of the whole stage converter and the half bridge inverter of the half stage converter.
11 . The apparatus of claim 10 , wherein:
a primary winding of the transformer is coupled to the half bridge inverter of the whole stage converter; and
a secondary winding of the transformer is coupled to the half bridge inverter of the half stage converter.
12 . The apparatus of claim 1 , wherein:
the switching speed increases to greater to at least 1 MHz; and
the efficiency of the half bridge inverter is at least 99 percent.
13 . An apparatus comprising:
a bidirectional direct current (DC)/alternating current (AC) circuit having a 1.5 stage topology comprising:
a whole stage converter comprising a half bridge inverter configured to transform a DC voltage to an always positive half sine wave having a first voltage, wherein when operating in a soft switching mode, a switching speed of the half bridge inverter increases without degrading an efficiency of the half bridge inverter; and
an isolated, unregulated, resonant DC/AC half stage converter in electrical communication with the whole stage converter, the isolated, unregulated, resonant DC/AC half stage converter having a fixed-gain, the isolated, unregulated, resonant DC/AC half stage converter comprising a half bridge inverter configured to transform the always positive half sine wave having the first voltage into an always positive half sine wave having a second voltage that is higher than the first voltage, the isolated, unregulated, resonant DC/AC half stage converter further comprising an unfolding bridge inverter configured to transform the always positive half sine wave having the second voltage into a full sine wave.
14 . A method of manufacturing a circuit, the method comprising:
providing a whole stage converter of a bidirectional direct current (DC)/alternating current (AC) circuit having a 1.5 stage topology, the whole stage converter comprising a half bridge inverter configured to transform a DC voltage to an always positive half sine wave having a first voltage, wherein when operating in a soft switching mode, a switching speed of the half bridge inverter increases without degrading an efficiency of the half bridge inverter; and
providing a half stage converter of the bidirectional DC/AC circuit having the 1.5 stage topology, the half stage converter in electrical communication with the whole stage converter, the half stage converter having a fixed-gain, the half stage converter comprising a half bridge inverter configured to transform the always positive half sine wave having the first voltage to an always positive half sine wave having a second voltage that is higher than the first voltage, the half stage converter further comprising an unfolding bridge inverter configured to transform the always positive half sine wave having the second voltage into an AC power signal, and to supply the AC power signal to an electrical grid.
15 . The method of claim 14 , wherein the whole stage converter is non-isolated.
16 . The method of claim 14 , wherein the half stage converter is isolated.
17 . The method of claim 14 , wherein the half stage converter is unregulated.
18 . The method of claim 14 , positioning a voltage link in between the whole stage converter and the half stage converter.
19 . The method of claim 14 , further comprising a plurality of whole stage converters wired in parallel and in electrical communication with the half stage converter.