# US 2017/0288407 A1 · Renewable energy power generation systems

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- Number: US 2017/0288407 A1
- Document ID: US20170288407A1
- Status: Published application
- Kind: A1
- Application number: 15/632,259
- Filed: 2017-06-23
- Published: 2017-10-05
- Earliest claimed: 2011-11-25
- Assignees: SolarCity Corporation
- Applicants: SolarCity Corporation
- Inventors: Paul Garrity; Aaron Michael Jungreis
- Web page: https://patentgrep.com/patent/US20170288407A1

## CPC

- H02J 3/381: {Dispersed generators}
- H02J 1/10: Parallel operation of DC sources
- H02J 3/16: by adjustment of reactive power
- H02J 3/38: Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel
- H02J 3/46: Controlling the sharing of generated power between the generators, sources or networks
- H02J 3/48: Controlling the sharing of active power
- H02J 3/50: Controlling the sharing of reactive power
- H02M 5/458: using semiconductor devices only
- H02M 7/48: using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M 7/493: the static converters being arranged for operation in parallel
- H02J 3/18: Arrangements for adjusting, eliminating or compensating reactive power in networks
- H02J 13/1335: {involving a local wireless network, e.g. Wi-Fi®, ZigBee® or Bluetooth®}
- H02J 2101/24: Photovoltaics
- H02M 1/007: {Plural converter units in cascade (push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826)}
- H02M 1/10: Arrangements incorporating converting means for enabling loads to be operated at will from different kinds of power supplies, e.g. from AC or DC
- H02M 1/4208: {Arrangements for improving power factor of AC input}
- H02M 1/4225: {using a non-isolated boost converter}
- H02M 7/53871: {with automatic control of output voltage or current}
- Y02B 70/10: Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
- Y02E 10/56: Power conversion systems, e.g. maximum power point trackers
- Y02E 40/30: Reactive power compensation
- Y02E 40/70: Smart grids as climate change mitigation technology in the energy generation sector
- Y02E 60/00: Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y04S 10/00: Systems supporting electrical power generation, transmission or distribution
- Y04S 10/12: Monitoring or controlling equipment for energy generation units, e.g. distributed energy generation [DER] or load-side generation
- Y04S 10/123: the energy generation units being or involving renewable energy sources
- Y04S 10/22: Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units
- Y04S 40/126: using wireless data transmission
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y04S: SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS

## Abstract

We describe a modular adjustable power factor renewable energy inverter system. The system comprises a plurality of inverter modules having a switched capacitor across its ac power output, a power measurement system coupled to a communication interface, and a power factor controller to control switching of the capacitor. A system controller receives power data from each inverter module, sums the net level of ac power from each inverter, determines a number of said capacitors to switch based on the sum, and sends control data to an appropriate number of the inverter modules to switch the determined number of capacitors into/out of said parallel connection across their respective ac power outputs.

## Claims

### Claim 1

A power conditioning system for supplying AC power to an AC grid comprising:
a plurality of inverters, each of the plurality of inverters including a DC input for receiving DC power from an DC source and an AC output for supplying AC power; and
a controller configured to:
determine an AC power supplied by each inverter of the plurality of inverters;
calculate a total power supplied by the power conditioning system as a percentage of a total power capability of the power conditioning system; and
control a displacement power factor of the power conditioning system based on the percentage.

### Claim 2 (depends on 1)

The power conditioning system of claim 1, wherein each inverter of the plurality of inverters includes an output capacitance that can be coupled in parallel with the AC output of each respective inverter.

### Claim 3 (depends on 2)

The power conditioning system of claim 2 wherein a plurality of switching devices, one switching device for each respective inverter, controls the coupling of each output capacitance in parallel with the AC output of each respective inverter.

### Claim 4 (depends on 3)

The power conditioning system of claim 3 wherein the plurality of switching devices comprise triacs.

### Claim 5 (depends on 3)

The power conditioning system of claim 3 wherein the displacement power factor of the power conditioning system is controlled by controlling the plurality of switching devices.

### Claim 6 (depends on 5)

The power conditioning system of claim 5 wherein the controller provides a variable degree of power factor compensation by controlling each of the plurality of switching devices for a portion of an AC cycle.

### Claim 7 (depends on 1)

The power conditioning system of claim 1 wherein the controller is further configured to recognize when an inverter is added or removed from the plurality of inverters and compensate accordingly to maintain control of the displacement power factor of the power conditioning system.

### Claim 8 (depends on 1)

The power conditioning system of claim 1 wherein the controller communicates with each inverter of the plurality of inverters through a wireless communication network.

### Claim 9 (depends on 1)

The power conditioning system of claim 1 wherein the controller applies a threshold to the percentage such that when the percentage is below the threshold no compensation is performed, and when the percentage is above the threshold power factor compensation is employed to control the displacement power factor.

### Claim 10 (depends on 1)

The power conditioning system of claim 1, wherein each inverter of the plurality of inverters includes an inductor that can be coupled in series with the AC output of each respective inverter.

### Claim 11

A system comprising:
a plurality of inverters, each inverter of the plurality of inverters including:
a DC input, a DC to AC converter, an AC output, and a displacement power factor adjustment circuit; and
a controller, communicatively coupled to each of the plurality of inverters, the controller configured to determine a total power supplied by the system at a moment in time, to compare that to a maximum potential power of the system, and to activate a displacement power adjustment circuit of one or more of the plurality of inverters based on the comparison.

### Claim 12 (depends on 11)

The system of claim 11, wherein the displacement power factor adjustment circuit includes an output capacitance that can be coupled in parallel with the AC output of each respective inverter of the plurality of inverters.

### Claim 13 (depends on 12)

The system of claim 12 wherein a plurality of switching devices, one switching device for each respective inverter, controls the coupling of each output capacitance in parallel with the AC output of each respective inverter.

### Claim 14 (depends on 13)

The system of claim 13 wherein the plurality of switching devices comprise triacs.

### Claim 15 (depends on 13)

The system of claim 13 wherein a displacement power factor of the system is controlled by controlling the plurality of switching devices.

### Claim 16 (depends on 15)

The system of claim 15 wherein the controller provides a variable degree of power factor compensation by controlling each of the plurality of switching devices for a portion of an AC cycle.

### Claim 17 (depends on 11)

The system of claim 11 wherein the controller is further configured to recognize when an inverter is added or removed from the plurality of inverters and compensate accordingly to maintain control of a displacement power factor of the system.

### Claim 18 (depends on 11)

The system of claim 11 wherein the controller communicates with each inverter of the plurality of inverters through a wireless communication network.

### Claim 19 (depends on 11)

The system of claim 11 wherein the controller applies a threshold to the total power supplied by the system such that when the total power supplied is below the threshold no displacement power adjustment circuits are activated, and when the total power supplied is above the threshold displacement power adjustment circuits of one or more of the plurality of inverters are activated to control a displacement power factor of the system.

### Claim 20 (depends on 11)

The system of claim 11, wherein each inverter of the plurality of inverters includes an inductor that can be coupled in series with the AC output of each respective inverter.