Power conversion apparatus

• US 10,644,504 B2
• Filed: 06/22/2017
• Issued: 05/05/2020
• Est. Priority Date: 09/16/2016
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Kawai, Yu
• Primary Examiner(s): Deberadinis, Robert L
• Application Number:
  US16/310,269
• Publication Number:
  US 20190334346A1
• Time in Patent Office: 1,048 Days
• CPC Class Codes: H02J 1/10 Parallel operation of dc sources
• 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 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• 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: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

In an electrical power conversion apparatus including DC power sources, electric power converter units, and an electric power sharing regulator for regulating electric power on a basis of individual electric power converter units, when the plurality of electric power converter units connects thereto a plurality of DC power sources on their input sides, and is connected in parallel with one another on their output sides, three threshold values of rated electric power, electric power of the highest efficiency, and electric power of allowable efficiency receive attention from an efficiency characteristic of each of the electric power converter units, and the adjustment of electric power shared by each of the electric power converter units is performed by the electric power sharing regulator so that better efficiency is achieved when the apparatus is viewed in its entirety.

Claims

1. An electrical power conversion apparatus, comprising:

a plurality of electric power converter units being connected in parallel with one another, and each possessing electric power information indicating a relationship between a value of electric power and efficiency, and attribute information including information of a degree of operating priority being an operating order; and

an electric power sharing regulator for regulating, by responding to demanded electric power, electric power shared by each of the electric power converter units, wherein

the electric power sharing regulator supervises go/no-go determination of electrical power conversion operations of the electric power converter units with reference to the attribute information taken in possession from each of the electric power converter units, and regulates electric power in which each of the electric power converter units shares by utilizing a first electric-power threshold value corresponding to rated efficiency of each of the plurality of electric power converter units, a second electric-power threshold value corresponding to a highest efficiency of each of the plurality of electric power converter units, and a third electric-power threshold value corresponding to allowable efficiency being efficiency to become a reference of each of the plurality of electric power converter units, where the electric-power threshold values are pieces of information related to electric power information in the attribute information.

2. The electrical power conversion apparatus as set forth in claim 1, wherein

the attribute information includes information on parallel connection configurations at input ends of the plurality of electric power converter units and at output ends thereof;

and

the electric power sharing regulator sets a degree of operating priority of each of the electric power converter units by using the attribute information.

3. The electrical power conversion apparatus as set forth in claim 2, wherein the electric power sharing regulator selects, by responding to the demanded electric power, one operation mode from three types of operation modes of a first operation mode in which electric power adjustment of the electric power converter units is performed in a range from the first electric-power threshold value to the second electric-power threshold value and an output from an unwanted electric power converter unit is set at zero, a second operation mode in which electric power adjustment of the electric power converter units is performed in a range between the second electric-power threshold value and the third electric-power threshold value and an output from an unwanted electric power converter unit is set at zero, and a third operation mode in which electric power adjustment of the electric power converter units is performed in a range of the third electric-power threshold value or less and an output from an unwanted electric power converter unit is set at zero, whereby electric power in which each of the electric power converter units shares with one another is regulated by means of the electric power sharing regulator.

4. The electrical power conversion apparatus as set forth in claim 3, wherein

the first operation mode undertakes that charge-discharge electric-power of the electric power converter units other than an adjusting one of the electric power converter units is set at the first electric-power threshold value, the second electric-power threshold value or zero, when the demanded electric power is not less than a sum of the second electric-power threshold values of two or more of the electric power converter units, and that

charge-discharge electric-power of the electric power converter units other than an adjusting one of the electric power converter units is set at zero, when the demanded electric power is not less than the second electric-power threshold value of one of the electric power converter units;

the second operation mode undertakes that charge-discharge electric-power of the electric power converter units other than an adjusting one of the electric power converter units is set at the second electric-power threshold value, the third electric-power threshold value or zero, when there does not exist a case of electric power sharing which satisfies the first operation mode and when the demanded electric power is not less than a sum of the third electric-power threshold values of two or more of the electric power converter units, and that

charge-discharge electric-power of the electric power converter units other than an adjusting one of the electric power converter units is set at zero, when the demanded electric power is not less than the third electric-power threshold value of one of the electric power converter units; and

the third operation mode undertakes that charge-discharge electric-power of the electric power converter units other than an adjusting one of the electric power converter units is set at zero, when there does not exist a case of electric power sharing which satisfies the first operation mode or the second operation mode.

5. The electrical power conversion apparatus as set forth in claim 3, wherein

the first operation mode undertakes that charge-discharge electric-power of each of the electric power converter units is set so that efficiency thereof becomes highest by using said first efficiency characteristic in which efficiency of an electric power section between the approximated by using the rated efficiency and the highest efficiency, when the demanded electric power is not less than a sum of the second electric-power threshold values of at least one or more of the electric power converter units;

the second operation mode undertakes that charge-discharge electric-power of each of the electric power converter units is set so that efficiency thereof becomes highest by using a second efficiency characteristic in which efficiency of an electric power section between the second electric-power threshold value and the third electric-power threshold value is linearly approximated by using the highest efficiency and the allowable efficiency, when there does not exist a case of electric power sharing which satisfies the first operation mode and when the demanded electric power is not less than a sum of the third electric-power threshold values of at least one or more of the electric power converter units; and

the third operation mode undertakes that charge-discharge electric-power of the electric power converter units other than an adjusting one of the electric power converter units is set at zero, when there does not exist a case of electric power sharing which satisfies the first operation mode or the second operation mode.

6. The electrical power conversion apparatus as set forth in claim 3, wherein,

in a configuration in which a DC power source connected to an electric power converter unit has a device for supervising or monitoring the DC power source which can acquire any piece of information of go/no-go determination of electric charging, go/no-go determination of electric discharging, an upper limit of electric charging power and an upper limit of electric discharging power by means of the device for supervising or monitoring the DC power source,

the electric power converter unit performs limitation on a charging operation or discharging operation by responding to information of the device for supervising or monitoring the DC power source;

and

the electric power sharing regulator detects limitation on the charging operation or discharging operation, and limits electric power in which the electric power converter unit share with one another.

7. The electrical power conversion apparatus as set forth in claim 3, wherein, in a configuration in which a DC power source connected to an electric power converter unit is a power source of a mobile body, the electric power sharing regulator removes the electric power converter unit to which the mobile body is connected from an object of the first operation mode through the third operation mode, and preferentially charges with electricity into the DC power source.

8. The electrical power conversion apparatus as set forth in claim 2, wherein the electric power sharing regulator can input thereinto the first electric-power threshold value, and acquires, by using two pieces of information defined in advance which are a first ratio expressed from zero to one corresponding to the second electric-power threshold value and a second ratio expressed from zero to one corresponding to the third electric-power threshold value, the second electric-power threshold value with reference to a product of the first electric-power threshold value and the first ratio, and the third electric-power threshold value with reference to a product of the first electric-power threshold value and the second ratio.

9. The electrical power conversion apparatus as set forth in claim 2, wherein the electric power sharing regulator acquires the first electric-power threshold value through the third electric-power threshold value, when the first electric-power threshold value through the third electric-power threshold value are set in advance in the electric power converter units each.

10. The electrical power conversion apparatus as set forth in claim 2, wherein the electric power sharing regulator acquires the attribute information, when the first electric-power threshold value of the plurality of electric power converter units through the third electric-power threshold value thereof are set in advance in the electric power sharing regulator.

11. The electrical power conversion apparatus as set forth in claim 2, wherein the electric power sharing regulator acquires electric power information corresponding to the first electric-power threshold value through the third electric-power threshold value, and determines a degree of operating priority of each of the electric power converter units based on the electric power information.

12. The electrical power conversion apparatus as set forth in claim 2, wherein the electric power sharing regulator acquires attribute information of an electric power converter unit, and determines a degree of operating priority of the electric power converter unit based on the attribute information.

13. The electrical power conversion apparatus as set forth in claim 2, wherein the degree of operating priority is set in decreasing order of the first electric-power threshold value other than a case in which the degree of operating priority is modified through information related to a degree of operating priority given in advance.

14. The electrical power conversion apparatus as set forth in claim 2, wherein the electric power sharing regulator generates, by using information of the rated efficiency, that of the highest efficiency and that of allowable efficiency, a first efficiency characteristic in which efficiency of an electric power section between the first electric-power threshold value and the second electric-power threshold value is linearly approximated by using the rated efficiency and the highest efficiency, and generates thereby a second efficiency characteristic in which efficiency of an electric power section between the second electric-power threshold value and the third electric-power threshold value is linearly approximated by using the highest efficiency and the allowable efficiency.

15. The electrical power conversion apparatus as set forth in claim 2, wherein values of the first electric-power threshold value through the third electric-power threshold value are modified, with respect to an input voltage and an output voltage of an electric power converter unit, by responding to either one or both of their voltage'"'"'s magnitudes.