Electric power conversion apparatus

• US 9,401,665 B2
• Filed: 09/15/2014
• Issued: 07/26/2016
• Est. Priority Date: 09/17/2013
• Status: Active Grant

• Current Assignee: LSIS Co. Ltd. (LS Corporation), Seoul National University R&DB Foundation (Seoul National University)
• Original Assignee: LSIS Co. Ltd. (LS Corporation), Seoul National University R&DB Foundation (Seoul National University)
• Inventors: Shin, Ho Joon, Hyung, Kwon Yub, Yoo, Anno, Ha, Jung Ik
• Primary Examiner(s): Dole, Timothy J
• Assistant Examiner(s): JAMALI, ISHRAT F
• Application Number:
  US14/486,568
• Publication Number:
  US 20150078049A1
• Time in Patent Office: 680 Days
• US Class Current: 1/1
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2300/26 involving maximum power point tracking control for photovoltaic sources maximum power point systems in particular G05F1/67
• 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: H02M 1/0025 Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
• CPC Class Codes: H02M 1/0048 Circuits or arrangements for reducing losses using snubbers H02M1/34
• CPC Class Codes: H02M 1/0054 Transistor switching losses periodically suspending operation of switching converter in low power mode H02M1/0035
• 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 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 7/48 using discharge tubes with control electrode or semiconductor devices with control electrode
• CPC Class Codes: H02M 7/4807 having a high frequency intermediate AC stage
• CPC Class Codes: H02M 7/4826 operating from a resonant DC source, i.e. the DC input voltage varies periodically, e.g. resonant DC-link inverters
• CPC Class Codes: H02M 7/53871 with automatic control of output voltage or current
• CPC Class Codes: Y02B 10/10 Photovoltaic [PV]
• 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

Abstract

The disclosure relates to an electric power conversion apparatus, and capable of determining a minimum output voltage of a boost converter based on a voltage of the grid, and comparing the minimum output voltage of the converter with an input voltage of the converter, and controlling the operation of the converter based on the comparison result, thereby reducing the unnecessary operation and switching loss of the converter, the electric power conversion apparatus according to the invention comprises a converter; and a control unit configured to detect a grid voltage to determine a minimum output voltage of the converter based on the grid voltage, and control the operation of the converter based on an input voltage of the converter and the determined minimum output voltage.

Claims

1. An electric power conversion apparatus, comprising:

a converter;

a control unit configured to detect a grid voltage so that the control unit determines a minimum output voltage of the converter based on the grid voltage, and control the operation of the converter based on an input voltage of the converter and the determined minimum output voltage;

an inverter linked to an output stage of the converter; and

an LC filter between the inverter and a grid,

wherein the inverter is configured with a DC/AC inverter linked to the grid to convert a DC voltage output from the converter into a commercial AC voltage that can be used in the grid,

wherein the control unit comprises;

a first controller configured to detect an input voltage of the converter; and

a second controller configured to detect an input/output voltage of the inverter,

wherein the first controller and the second controller are further configured to transmit and receive voltage information detected therebetween,

wherein the first controller is further configured to detect an input voltage of the converter so that the first controller compares the input voltage with the determined minimum output voltage information transmitted from the second controller, and controls the switching operation of the converter based on the comparison result, and

the second controller is further configured to detect a voltage of the grid so that the second controller determines a minimum output voltage of the converter based on the grid voltage and transmits the determined minimum output voltage information to the first controller.

2. The electric power conversion apparatus of claim 1, wherein the converter comprises a DC/DC boost converter for boosting the DC voltage to a predetermined voltage.

3. The electric power conversion apparatus of claim 1, wherein the minimum output voltage of the converter is configured with a minimum voltage capable of delivering maximum electric power to the grid.

4. The electric power conversion apparatus of claim 1, wherein the control unit is further configured to compare a size of the input voltage of the converter with a size of the determined minimum output voltage to control the operation of the converter to be stopped when the input voltage of the converter is equal to or greater than the determined minimum output voltage.

5. The electric power conversion apparatus of claim 1, wherein the first controller is further configured to control the switch of the converter so that the switch is open so as to stop the operation of the converter when the input voltage of the converter is higher than the determined minimum output voltage.

6. The electric power conversion apparatus of claim 1, further comprising:

a plurality of converters linked to a plurality of generators, respectively,

wherein the control unit is further configured to detect input voltages of the plurality of converters, respectively, and control the operation of the converter so that the highest voltage among input voltages of the plurality of converters and the determined minimum output voltage to be an output voltage of the converter.

7. An electric power conversion apparatus, comprising:

a converter;

a control unit configured to detect a grid voltage so that the control unit determines a minimum output voltage of the converter based on the grid voltage, and control the operation of the converter based on an input voltage of the converter and the determined minimum output voltage;

an inverter linked to an output stage of the converter; and

an LC filter between the inverter and a grid,

wherein the inverter is configured with a DC/AC inverter linked to the grid to convert a DC voltage output from the converter into a commercial AC voltage that can be used in the grid,

wherein the control unit comprises;

a first controller configured to detect an input voltage of the converter; and

a second controller configured to detect an input/output voltage of the inverter,

wherein the first controller and the second controller are further configured to transmit and receive voltage information detected therebetween,

wherein the first controller is further configured to detect the input voltage of the converter so that the first controller transmits the input voltage information of the converter to the second controller, and

wherein the second controller is further configured to detect a voltage of the grid so that the second controller determines a minimum output voltage of the converter based on the grid voltage, and compares the minimum output voltage with the input voltage information of the converter transmitted from the first controller, and controls the boosting operation of the converter based on the comparison result.

8. The electric power conversion apparatus of claim 7, wherein when the input voltage of the converter is higher than the minimum output voltage, the second controller is further configured to control the output voltage of the converter to be set to the same as the input voltage of the converter so as to stop the boosting operation of the converter.