阅读说明：本技术 电力变换装置、电力变换系统以及电力变换装置的运转方法 (Power conversion device, power conversion system, and method for operating power conversion device ) 是由 川井由宇 嘉藤贵洋 于 2018-02-16 设计创作，主要内容包括：在并联复用有多个电力变换单元的结构中，所述电力变换单元具备用于在电源与负载之间进行电力变换的电力变换器，多个电力变换单元中的至少一个电力变换单元具备管理电力变换器(11)的运转的运转管理部(13)，运转管理部(13)使输入作为目标电压和负载侧的电压的差的稳态偏差而进行比例控制的电压调整部(121)的比例增益变化，比较比例增益的变化和稳态偏差的变化，从而判定是否是除了自身的电力变换单元以外的其他电力变换单元未运转的单独运转。(In a configuration in which a plurality of power conversion units are multiplexed in parallel, the power conversion unit includes a power converter for performing power conversion between a power source and a load, at least one of the plurality of power conversion units includes an operation management unit (13) for managing the operation of the power converter (11), and the operation management unit (13) determines whether or not the power conversion unit is an independent operation in which the other power conversion units other than the power conversion unit itself are not operated by changing a proportional gain of a voltage adjustment unit (121) to which proportional control is performed by changing a steady-state deviation of a difference between a target voltage and a voltage on the load side, and comparing the change in the proportional gain with the change in the steady-state deviation.)

1. A power conversion device is configured to include a plurality of power conversion units, each of which is connected in parallel on a load side, the power conversion unit including: a power converter for performing power conversion between a power source and the load and having a direct current on a load side; and a voltage controller including a voltage adjustment unit that receives a steady-state deviation of a difference between a target voltage and the load-side voltage and performs proportional control so as to control the load-side voltage of the power converter to the target voltage,

at least one of the plurality of power conversion units includes an operation management unit that manages operation of the power conversion unit, and the operation management unit changes the proportional gain of the proportional control of the voltage adjustment unit, compares the change in the proportional gain with the change in the steady-state deviation, and determines whether or not the power conversion unit other than the power conversion unit itself is in an independent operation in which the other power conversion unit is not in operation.

2. The power conversion device according to claim 1,

the estimated resistance value or estimated power value of the load before and after the change of the proportional gain is obtained by using the voltage on the load side and the target current value as the output of the voltage adjustment unit, and the change of the proportional gain and the change of the steady-state deviation are compared.

3. The power conversion device according to claim 1 or 2,

the power conversion device includes a plurality of power conversion units having the operation management unit, the plurality of power conversion units having the operation management unit are each provided with an independent identification number, and the start timing of the process of changing the proportional gain of each power conversion unit for determining whether or not the power conversion unit is operated independently differs for each identification number.

4. The power conversion device according to any one of claims 1 to 3,

the operation management unit stops the power conversion operation of the power conversion unit when the power of the power conversion unit is equal to or less than a preset power threshold of the power conversion unit and when it is determined that the power conversion unit is not operated alone but is operated in parallel with other power conversion units.

5. The power conversion device according to claim 4,

the operation management unit starts the power conversion operation of the power conversion unit when the voltage on the load side becomes equal to or less than a reference value that is set in advance to a voltage lower than the target voltage after stopping the power conversion operation of the power conversion unit.

6. The power conversion device according to claim 4,

the operation management unit starts the power conversion operation of the power conversion unit when the voltage on the load side becomes equal to or higher than a reference value that is set in advance to a voltage higher than the target voltage after stopping the power conversion operation of the power conversion unit.

7. A power conversion system is characterized by comprising: the power conversion device according to claim 6; and a load connected to the power conversion device and including a power generation mechanism.

8. An operation method of a power conversion device configured to include a plurality of power conversion units, each of the power conversion units being connected in parallel on a load side, the power conversion unit comprising: a power converter connected between a power source and the load and having a direct current on a load side; and a voltage controller including a voltage adjustment unit that receives a steady-state deviation between a target voltage and a voltage on the load side and performs proportional control so as to control the voltage on the load side of the power converter to the target voltage, wherein the method for operating the power converter includes:

in at least one of the plurality of power conversion units, a proportional gain of the proportional control of the voltage adjustment unit is changed, and the change in the proportional gain and the change in the steady-state deviation are compared to determine whether or not the power conversion unit is a parallel operation in which the other power conversion units than the power conversion unit itself are operated; and

when the power supplied to the load by the power conversion unit of the self is less than the preset power threshold of.

9. The method of operating a power conversion apparatus according to claim 8,

the method for operating the power conversion device comprises the following steps: when the voltage on the load side becomes equal to or lower than a reference value that is set in advance to a voltage lower than the target voltage after the power conversion operation of the power conversion unit itself is stopped, the power conversion operation of the power conversion unit itself is started.

10. The method of operating a power conversion apparatus according to claim 8,

the method for operating the power conversion device comprises the following steps: when the voltage on the load side becomes equal to or higher than a reference value that is set in advance to a voltage higher than the target voltage after the power conversion operation of the power conversion unit itself is stopped, the power conversion operation of the power conversion unit itself is started.

Technical Field

The present invention relates to a power conversion device having a configuration in which power conversion units are multiplexed in parallel.

Background

The parallel multiplexing structure of the power conversion unit is receiving attention as a design relaxation technology that does not require a custom design corresponding to a required specification. In the case of controlling the voltage of the parallel connection terminals in a parallel system in which a control function is independently provided for each power conversion unit, a function of averaging electric power is required in order to avoid concentration of electric power to a specific power conversion unit (for example, patent document 1).

Disclosure of Invention

In patent document 1, the switching power supply corresponding to the power conversion unit has a droop characteristic, and therefore, the problem of power concentration to a specific individual when parallel multiplexing is performed can be alleviated. However, since it is impossible to detect whether or not the individual operation is performed, it is difficult to stop the power conversion operation of several units for improving efficiency in the continuous operation in the parallel multiplexing situation, and it is necessary to always send power from all the power conversion units.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a power converter using power conversion units that can be multiplexed in parallel, in which the power conversion units can determine whether or not they are operating alone without using information from the outside of the power conversion units themselves.

The power conversion device disclosed in the present application is configured to include a plurality of power conversion units, each of which is connected in parallel on a load side, the power conversion units including: a power converter for performing power conversion between a power source and the load and having a direct current on a load side; and a voltage controller including a voltage adjustment unit that receives a steady-state offset (steady-state offset) that is a difference between a target voltage and a voltage on a load side and performs proportional control so as to control the voltage on the load side of the power converter to the target voltage, wherein at least one of the plurality of power conversion units includes an operation management unit that manages operation of the power conversion unit, and the operation management unit determines whether or not the power conversion unit other than the power conversion unit itself is operating alone by changing a proportional gain of the proportional control of the voltage adjustment unit and comparing the change in the proportional gain with the change in the steady-state offset.

According to the power conversion device disclosed in the present application, one of the plurality of power conversion units whose output ends are connected in parallel can individually determine whether or not its own power conversion unit is operating alone without using information from the outside of its own power conversion unit.

Drawings

Fig. 1 is a block diagram showing a configuration of a power conversion system including a power conversion device according to embodiment 1.

Fig. 2 is a block diagram showing the configuration of a power conversion system including another power conversion device according to embodiment 1.

Fig. 3 is a circuit diagram showing a detailed configuration example of the power conversion unit of fig. 1.

Fig. 4 is a circuit diagram showing a detailed configuration example of the power conversion unit of fig. 2.

Fig. 5 is a diagram schematically showing a control block of a control system of a power conversion unit of the power conversion device according to embodiment 1.

Fig. 6 is a schematic diagram for explaining an operation in a case where the power conversion unit of the power conversion device according to embodiment 1 is operated alone.

Fig. 7 is a schematic diagram for explaining an operation in the case where the power conversion units of the power conversion device according to embodiment 1 are operated in parallel.

Fig. 8 is a schematic diagram for explaining another operation in the case where the power conversion units of the power conversion device according to embodiment 1 are operated in parallel.

Fig. 9 is a flowchart for explaining the operation of the power converter according to embodiment 1.

Fig. 10 is a flowchart for explaining the operation of the power converter according to embodiment 2.

Fig. 11 is a graph showing characteristics of a specific example of the power converter according to embodiment 2.

Fig. 12 is a graph for explaining the effects of the power converter according to embodiment 2.

Fig. 13 is a block diagram showing the configuration of a power conversion system including a power conversion device according to embodiment 3.

Fig. 14 is a block diagram showing an example of a hardware configuration of the voltage controller and the operation management unit of the power conversion device.

(symbol description)

10. 10-1, 10-2, 10-N: a power conversion unit; 11: a power converter; 12: a voltage controller; 13: an operation management unit; 15: a voltage sensor; 20-1, 20-2, 20-N: a direct current power supply; 21-1, 21-2, 21-N: an alternating current power supply; 30: a load; 31: a power consuming load; 32: a power generation mechanism; 121: and a voltage adjusting part.

Detailed Description