Renewable energy power generation systems

• US 10,056,759 B2
• Filed: 06/23/2017
• Issued: 08/21/2018
• Est. Priority Date: 11/25/2011
• Status: Active Grant

• Current Assignee: Tesla Inc.
• Original Assignee: Tesla Inc.
• Inventors: Garrity, Paul, Jungreis, Aaron Michael
• Primary Examiner(s): Tran, Nguyen
• Application Number:
  US15/632,259
• Publication Number:
  US 20170288407A1
• Time in Patent Office: 424 Days
• Field of Search: 363 65- 72, 307 82
• CPC Class Codes: H02J 1/10 Parallel operation of dc sources
• CPC Class Codes: H02J 13/00026 involving a local wireless network, e.g. Wi-Fi, ZigBee or Bluetooth
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/16 by adjustment of reactive power
• CPC Class Codes: H02J 3/18 Arrangements for adjusting, eliminating or compensating reactive power in networks for adjustment of voltage H02J3/16
• CPC Class Codes: H02J 3/38 Arrangements for parallely feeding a single network by two or more generators, converters or transformers
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: H02J 3/48 Controlling the sharing of the in-phase component
• CPC Class Codes: H02J 3/50 Controlling the sharing of the out-of-phase component
• CPC Class Codes: 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
• CPC Class Codes: 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
• CPC Class Codes: H02M 1/4208 Arrangements for improving power factor of AC input
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 5/458 using semiconductor devices only
• CPC Class Codes: H02M 7/48 using discharge tubes with control electrode or semiconductor devices with control electrode
• CPC Class Codes: H02M 7/493 the static converters being arranged for operation in parallel
• CPC Class Codes: H02M 7/53871 with automatic control of output voltage or current
• CPC Class Codes: 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
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 40/30 : Reactive power compensation
• CPC Class Codes: Y02E 40/70 : Smart grids as climate change mitigation technology in the energy generation sector
• CPC Class Codes: Y02E 60/00 : Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/00 : Systems supporting electrical power generation, transmission or distribution
• CPC Class Codes: Y04S 10/12 : Monitoring or controlling equipment for energy generation units, e.g. distributed energy generation [DER] or load-side generation
• CPC Class Codes: Y04S 10/123 : the energy generation units being or involving renewable energy sources
• CPC Class Codes: Y04S 10/22 : Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units
• CPC Class Codes: Y04S 40/126 : using wireless data transmission

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

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.

2. 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.

3. 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.

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

5. 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.

6. 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.

7. 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.

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

9. 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.

10. 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.