Parallel battery system
View Patent ↗Apparatus for power conversion. In one embodiment, the apparatus comprises a battery unit, coupled to a power line, comprising (a) a plurality of power cells, wherein each power cell of the plurality of power cells comprises a battery cell coupled to a pico-converter, wherein the pico-converter is a bidirectional power converter; and (b) a master controller, coupled to each power cell of the plurality of power cells, for dynamically and individually controlling both an operating state and a power conversion direction for each power cell in the plurality of power cells to generate a predetermined power output from the battery unit.
1. Apparatus for power conversion, comprising:
a battery unit, coupled to a power line, comprising:
a plurality of power cells coupled in parallel, wherein each power cell of the plurality of power cells comprises a battery cell coupled to a pico-converter, wherein the pico-converter is a bidirectional power converter; and
a master controller, coupled to each power cell of the plurality of power cells, for dynamically and individually controlling both an operating state and a power conversion direction for each power cell in the plurality of power cells to generate a predetermined power output from the battery unit, wherein each pico-converter of the plurality of power cells is a bidirectional DC-AC inverter, the power line is an AC power line, and the predetermined power output is an AC power output.
2. The apparatus of claim 1 , wherein each power cell of the plurality of power cells comprises (i) a first input, coupled to the master controller, for receiving an operating state control signal from the master controller indicating the operating state, (ii) a second input, coupled to the master controller, for receiving a power conversion direction control signal indicating the power conversion direction, and (iii) a feedback output, coupled to the master controller, for providing a feedback signal to the master controller.
3. The apparatus of claim 2 , wherein the master controller issues both the operating state control signal and the power conversion direction control signal in real-time for each power cell in the plurality of power cells based on the feedback signal received from each power cell in the plurality of power cells.
4. The apparatus of claim 1 , wherein the operating state is either active or inactive.
5. The apparatus of claim 1 , wherein the master controller controls each power cell in the plurality of power cells to spread current and thermal losses over the plurality of power cells.
6. The apparatus of claim 1 , wherein, for each power cell of the plurality of power cells, controlling the power conversion direction comprises controlling the pico-converter to either charge the battery cell or discharge the battery cell.
7. The apparatus of claim 1 , wherein the master controller controls at least one power cell of the plurality of power cells to fully charge the corresponding battery cell.
8. The apparatus of claim 1 , wherein the master controller controls each power cell in the plurality of power cells to synthesize a grid-compliant current waveform at the output of the battery unit.
9. The apparatus of claim 1 , wherein the master controller individually controls each active power cell in the plurality of power cells to generate a discrete amount of output power such that the sum of the output power from each active power cell in the plurality of power cells is equal to the AC power output.
10. The apparatus of claim 9 , wherein the discrete amount of the output power from each active power cell in the plurality of power cells is the same.
11. The apparatus of claim 9 , wherein the discrete amount of the output power from each active power cell in the plurality of power cells is not the same.
12. The apparatus of claim 2 , wherein the master controller issues both the operating state control signal and the power conversion direction control signal in real-time for each power cell in the plurality of power cells based on (i) the feedback signal received from each power cell in the plurality of power cells, and (ii) an AC line reference signal from the AC power line.
13. The apparatus claim 1 , wherein each pico-converter of the plurality of power cells is a single-phase DC-AC inverter.
14. The apparatus of claim 13 , wherein a first group of power cells of the plurality of power cells is coupled to a first conductor line of the power line, a second group of power cells of the plurality of power cells is coupled to a second conductor line of the power line, and the master controller controls the plurality of power cells to generate a split-phase AC output from the battery unit.
15. The apparatus of claim 13 , wherein a first group of power cells of the plurality of power cells is coupled to a first conductor line of the power line, a second group of power cells of the plurality of power cells is coupled to a second conductor line of the power line, a third group of power cells of the plurality of power cells is coupled to a third conductor line of the power line, and the master controller controls the plurality of power cells to generate a three-phase AC output from the battery unit.
16. The apparatus of claim 13 , wherein the pico-converter of the plurality of power cells is a resonant converter comprising a piezoelectric transformer.
17. The apparatus of claim 1 , wherein each pico-converter of the plurality of power cells processes on the order of 3 W of power.
18. The apparatus of claim 1 , wherein the master controller uses power line communications for communicating via the power line.