阅读说明：本技术 一种光伏多端口系统能量流动控制方法及协调控制器 (Photovoltaic multi-port system energy flow control method and coordination controller ) 是由 王瑞 杜智亮 刘毓聪 秦健峰 张宏阳 肖飞 黄辉 魏亚龙 于 2021-09-23 设计创作，主要内容包括：本发明提供了一种光伏多端口系统能量流动控制方法及协调控制器,包括：协调控制器收集当前各端口的运行信息,判断各端口运行状态并进行功率协调；直流母线电压检测及范围判断,光伏端口对直流母线电压进行检测并进行电压范围判断；光伏分级控制,针对直流母线电压所处的不同范围,光伏端口分级采用不同的控制方式。本发明根据实际工况划分直流母线电压范围,光伏端口针对各个工况采取不同控制方式,可优化系统控制效果,同时可快速有效平抑多端口直流母线电压过冲。(The invention provides a photovoltaic multi-port system energy flow control method and a coordination controller, comprising the following steps: the coordination controller collects the current running information of each port, judges the running state of each port and coordinates the power; detecting and judging the range of the voltage of the direct current bus, and detecting the voltage of the direct current bus and judging the voltage range by the photovoltaic port; and photovoltaic hierarchical control, wherein different control modes are adopted by photovoltaic ports in a hierarchical manner aiming at different ranges of the voltage of the direct current bus. According to the invention, the direct current bus voltage range is divided according to the actual working conditions, and the photovoltaic port adopts different control modes aiming at each working condition, so that the system control effect can be optimized, and meanwhile, the multi-port direct current bus voltage overshoot can be quickly and effectively stabilized.)

1. A photovoltaic multi-port system energy flow control method is characterized in that converters of different types are connected to a direct current bus of a multi-port system, and the multi-port system comprises a coordination controller, a photovoltaic port and a load consumption port; the method is characterized in that the coordination controller collects the current operation information of each port and performs hierarchical control on the photovoltaic ports:

if the DC bus voltage U_DCAt the upper bus voltage deviation set value U_{DC_up}And the lower bus voltage deviation set value U_{DC_down}In between, the photovoltaic port tracks the maximum power P of the photovoltaic cell panel_MPPOutputting or outputting a specified power;

if the DC bus voltage U_DCLess than (100-x)% U_{DC_down}Or greater than x% U_{DC_up}The photovoltaic port works in a direct current bus voltage deviation control state;

if the DC bus voltage U_DCLess than (100-y)% U_{DC_down}Or higher than y% U_{DC_up}The photovoltaic port works in a fixed duty ratio control state; y is more than x;

if the DC bus voltage U_DCLess than 90% U_{DC_down}Or greater than 10% U_{DC_up}And the photovoltaic port seals the pulse, and the voltage conversion and the active power output are not carried out any more.

2. The photovoltaic multiport system energy flow control method in claim 1, characterized in that x is 1, 2, 3, 4 or 5 and y is 6, 7, 8, 9 or 10.

3. The photovoltaic multiport system energy flow control method according to claim 1 or 2, characterized in that the bus bar voltage deviation control state comprises: if the DC bus voltage U_DCLess than (100-x)% U_{DC_down}The photovoltaic port then stabilizes the DC bus voltage at (100-x)% U_{DC_down}(ii) a If the DC bus voltage U_DCHigher than x% U_{DC_up}Then the photovoltaic port stabilizes the dc bus voltage at x% U_{DC_up}。

4. The photovoltaic multiport system energy flow control method according to claim 1 or 2, characterized in that the fixed duty cycle D' calculation comprises:

U_ocis the open circuit voltage at the input side of the photovoltaic port.

5. A photovoltaic multi-port system coordination controller is characterized in that different types of converters are connected to a direct current bus of a multi-port system, and the multi-port system comprises a coordination controller, a photovoltaic access port and a load consumption port; the coordination controller is characterized by comprising an acquisition module, a judgment module and a communication module;

the acquisition module collects the current operation information of each port;

the judging module is used for judging whether the direct current bus voltage U is greater than the direct current bus voltage U_DCAt the upper bus voltage deviation set value U_{DC_up}And the lower bus voltage deviation set value U_{DC_down}Starting the power control function of the photovoltaic port to realize the maximum power P of the photovoltaic cell panel_MPPOutputting or outputting a specified power;

if the DC bus voltage U_DCLess than (100-x)% U_{DC_down}Or greater than x% U_{DC_up}If so, starting a bus voltage deviation control function of the photovoltaic port, and controlling the photovoltaic port to work in a direct current bus voltage deviation control state;

if the DC bus voltage U_DCLess than (100-y)% U_{DC_down}Or higher than y% U_{DC_up}If so, starting a fixed duty ratio control function of the photovoltaic port, and controlling the photovoltaic port to work at a fixed duty ratio; y is more than x;

if the DC bus voltage U_DCLess than 90% U_{DC_down}Or greater than 10% U_{DC_up}And then, the photovoltaic port is subjected to pulse sealing control, and the photovoltaic port is controlled not to perform voltage conversion and actively output power any more.

And the communication module transmits the photovoltaic port function obtained by the coordination controller through the judgment module to the photovoltaic converter.

6. The photovoltaic multi-port system coordinating controller of claim 5, wherein x is 1, 2, 3, 4 or 5 and y is 6, 7, 8, 9 or 10.

7. The photovoltaic multi-port system coordinated controller according to claim 5 or 6, wherein the busbar bias control function comprises: if the DC bus voltage U_DCLess than (100-x)% U_{DC_down}The photovoltaic port then stabilizes the DC bus voltage at (100-x)% U_{DC_down}(ii) a If the DC bus voltage U_DCHigher than x% U_{DC_up}Then the photovoltaic port stabilizes the dc bus voltage at x% U_{DC_up}。

8. The photovoltaic multi-port system coordinated controller according to claim 5 or 6, wherein the fixed duty cycle function comprises a fixed duty cycle D' calculation:

U_ocis the open circuit voltage at the input side of the photovoltaic port.

Technical Field

The invention relates to the technical field of power electronics, in particular to a photovoltaic multi-port system energy flow control method and a coordination controller.

Background

With the continuous development of new energy and the continuous development of new energy technology, the power generation mode is changing from the original traditional single centralized power generation to the distributed and centralized concurrent power generation mode. However, due to the characteristics of randomness, intermittence, dispersity and the like of new energy, when a single new energy is connected into a power grid, the situation of insufficient power transmission is easily caused, the generated multi-port system can realize input, output, conversion and storage of different energy carriers, interconnection and complementation of different energy forms, organic communication of production and consumption links and fusion of energy source flows with different characteristics.

At present, research work on multiple ports comprises framework construction of a multi-port system and access and coordination control of multiple energy sources, energy can flow in multiple directions through reasonable coordination control, and alternating current and direct current interfaces, voltage regulation functions and the like are provided. When a photovoltaic access multi-port system is mostly operated in a Maximum Power Point Tracking (MPPT) mode, for example, a chinese patent with a publication number of CN110867897A, the purpose of system energy flow is achieved through functions of other ports. However, the multi-port system has various compositions, and the photovoltaic port in each system does not need to realize maximum power tracking, when other energy ports in the multi-port system are stopped due to a fault, the photovoltaic port working in the MPPT mode continuously inputs power to the common direct current bus, and the bus voltage is raised, or even other port devices are damaged. When other energy source ports in the multi-port system do not have the off-grid starting function, the photovoltaic port serving as a power generation source needs to bear the initial bus voltage establishment to provide starting conditions for the other ports and the like. It is therefore essential that the control scheme for the photovoltaic ports in a multi-port system be complete.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a photovoltaic multi-port system energy flow control method and a coordination controller, which can improve the utilization efficiency of a photovoltaic port and optimize the control effect of a photovoltaic multi-port-based system.

In order to achieve the aim, the invention provides a photovoltaic multi-port system energy flow control method, wherein different types of converters are connected to a direct current bus of a multi-port system, and the multi-port system comprises a coordination controller, a photovoltaic port and a load consumption port; the coordination controller collects the current operation information of each port and performs hierarchical control on the photovoltaic ports:

if the DC bus voltage U_DCAt the upper bus voltage deviation set value U_{DC_up}And the lower bus voltage deviation set value U_{DC_down}In between, the photovoltaic port tracks the maximum power P of the photovoltaic cell panel_MPPOutputting or outputting a specified power;

if the DC bus voltage U_DCLess than (100-x)% U_{DC_down}Or greater than x% U_{DC_up}The photovoltaic port works in a direct current bus voltage deviation control state;

if the DC bus voltage U_DCLess than (100-y)% U_{DC_down}Or higher than y% U_{DC_up}The photovoltaic port works in a fixed duty ratio control state; y is more than x;

if the DC bus voltage U_DCLess than 90% U_{DC_down}Or greater than 10% U_{DC_up}And the photovoltaic port seals the pulse, and the voltage conversion and the active power output are not carried out any more.

Further, x is 1, 2, 3, 4 or 5, and y is 6, 7, 8, 9 or 10.

Further, the bus voltage deviation control state comprises: if the DC bus voltage U_DCLess than (100-x)% U_{DC_down}The photovoltaic port then stabilizes the DC bus voltage at (100-x)% U_{DC_down}(ii) a If the DC bus voltage U_DCHigher than x% U_{DC_up}The photovoltaic port stabilizes the dc bus voltage at x% U_{DC_up}。

Further, the fixed duty cycle D' calculation includes:

U_ocis the open circuit voltage at the input side of the photovoltaic port.

On the other hand, a photovoltaic multi-port system coordination controller is provided, wherein different types of converters are connected to a direct current bus of a multi-port system, the multi-port system comprises a coordination controller, a photovoltaic access port and a load consumption port, and the coordination controller comprises an acquisition module, a judgment module and a communication module;

the acquisition module collects the current operation information of each port;

the judging module is used for judging whether the direct current bus voltage U is greater than the direct current bus voltage U_DCAt the upper bus voltage deviation set value U_{DC_up}And the lower bus voltage deviation set value U_{DC_down}Starting the power control function of the photovoltaic port to realize the maximum power P of the photovoltaic cell panel_MPPOutputting or outputting a specified power;

if the DC bus voltage U_DCLess than (100-x)% U_{DC_down}Or greater than x% U_{DC_up}If so, starting a bus voltage deviation control function of the photovoltaic port, and controlling the photovoltaic port to work in a direct current bus voltage deviation control state;

if the DC bus voltage U_DCLess than (100-y)% U_{DC_down}Or higher than y% U_{DC_up}If so, starting a fixed duty ratio control function of the photovoltaic port, and controlling the photovoltaic port to work at a fixed duty ratio; y is more than x;

if the DC bus voltage U_DCLess than 90% U_{DC_down}Or greater than 10% U_{DC_up}Then, the photovoltaic port is subjected to pulse sealing control and controlThe photovoltaic port no longer performs voltage conversion and active power output.

And the communication module transmits the photovoltaic port function obtained by the coordination controller through the judgment module to the photovoltaic converter.

Further, x is 1, 2, 3, 4 or 5, and y is 6, 7, 8, 9 or 10.

Further, the bus bar deviation control function includes: if the DC bus voltage U_DCLess than (100-x)% U_{DC_down}The photovoltaic port then stabilizes the DC bus voltage at (100-x)% U_{DC_down}(ii) a If the DC bus voltage U_DCHigher than x% U_{DC_up}Then the photovoltaic port stabilizes the dc bus voltage at x% U_{DC_up}。

Further, the fixed duty cycle function includes a fixed duty cycle D' calculation:

U_ocis the open circuit voltage at the input side of the photovoltaic port.

The technical scheme of the invention has the following beneficial technical effects:

(1) according to the invention, the voltage range of the direct current bus is divided according to the actual working conditions, and the photovoltaic port adopts different control modes aiming at each working condition, so that the control effect of the system is optimized. The control method can still enable the system to stably operate after other ports in the multi-port system are abnormal, thereby realizing the response of various emergency working conditions and improving the stability and reliability of the system.

(2) The control method can quickly and effectively stabilize voltage overshoot of the multi-port direct current bus.

(3) The photovoltaic multi-port system energy flow control method and the coordination controller can be suitable for various multi-port systems with photovoltaic ports.

Drawings

FIG. 1 is a flow chart of a photovoltaic multiport system energy flow control method;

FIG. 2 is a block diagram of a common DC bus multiport system;

fig. 3 is a schematic diagram of a photovoltaic port grading strategy.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

The following description will be made with reference to the four-port system as an example, and with reference to the accompanying drawings:

FIG. 2 is a diagram of a four port system configuration defining a common DC bus voltage as U_DCThe upper bus voltage deviation set value is U_{DC_up}The deviation set value of the lower bus voltage is U_{DC_down}The input side voltage of the photovoltaic port is U_PVAnd the two DC/DC port sides are respectively connected with a load and an energy storage battery, and the DC/AC port is connected with a mains supply.

Referring to fig. 1, in the method for controlling energy flow of a photovoltaic multi-port system, a coordination controller acquires operation information of each port to perform hierarchical control. The method comprises the following steps:

(1) judging the running state of each port, including:

if at least one of the DC/AC converter connected with the mains supply and the DC/DC converter connected with the energy storage normally operates, the coordination controller regulates and controls the power flow of the photovoltaic port and the energy storage port (if the energy storage port normally operates) according to the power consumed by the current load, and at the moment, the photovoltaic port works in an MPPT mode or a power scheduling mode according to the command of the coordination controller.

If the DC/AC converter connected with the commercial power and the DC/DC converter connected with the stored energy are not operated, for example, fault shutdown and normal shutdown occur, a control command capable of being classified is sent to the photovoltaic port.

Referring to table 1, the photovoltaic port detects the dc bus voltage, and determines the range of the dc bus voltage, which is specifically listed in a table form.

TABLE 1

(2) The photovoltaic hierarchical control strategy, as shown in fig. 3, includes:

the working condition I is as follows: if the DC bus voltage U_DCAt the upper bus voltage deviation set value U_{DC_up}And the lower bus voltage deviation set value U_{DC_down}According to the instruction issued by the coordination controller, the photovoltaic port is kept in the MPPT working mode or the power limiting working mode, and the maximum output power P of the photovoltaic cell panel is tracked_MPPOr output a specified power.

Working conditions are as follows: if the DC bus voltage U_DCLess than (100-x)% U_{DC_down}Or greater than x% U_{DC_up}And taking x as 5, and enabling the photovoltaic port to work in a direct current bus voltage deviation control state.

If the DC bus voltage U_DCLess than (100-x)% U_{DC_down}The photovoltaic port then stabilizes the DC bus voltage at (100-x)% U_{DC_down}(ii) a If the DC bus voltage U_DCHigher than x% U_{DC_up}Then the photovoltaic port stabilizes the dc bus voltage at x% U_{DC_up}。

Working conditions are as follows: if the DC bus voltage U_DCLess than (100-y)% U_{DC_down}Or higher than y% U_{DC_up}Here, taking y as 10, the photovoltaic port operates in a fixed duty cycle control state, where the fixed duty cycle D' can be derived from the following equation:

U_ocis the open circuit voltage at the input side of the photovoltaic port.

Working conditions are as follows: if the DC bus voltage U_DCLess than 90% U_{DC_down}Or greater than 10% U_{DC_up}The photovoltaic port is sealed for pulse processing, and the photovoltaic port does not perform voltage conversion and active outputAnd (6) outputting power.

And under the first working condition, at least one working condition of normal operation is provided for the corresponding DC/AC converter of the mains supply and the DC/DC converter connected with the energy storage. The working conditions II, III and IV correspond to abnormal working conditions.

Another aspect provides a photovoltaic multi-port system coordination controller, wherein different types of converters are connected to a direct current bus of the multi-port system, and the multi-port system comprises a coordination controller, a photovoltaic access port and a load consumption port.

The coordination controller comprises an acquisition module, a judgment module and a communication module;

the acquisition module collects the current operation information of each port.

The judging module is used for judging whether the direct current bus voltage U is greater than the direct current bus voltage U_DCAt the upper bus voltage deviation set value U_{DC_up}And the lower bus voltage deviation set value U_{DC_down}Starting the power control function of the photovoltaic port to realize the maximum power P of the photovoltaic cell panel_MPPOutputting or outputting the specified power.

If the DC bus voltage U_DCLess than (100-x)% U_{DC_down}Or greater than x% U_{DC_up}And then starting a bus voltage deviation control function of the photovoltaic port to control the photovoltaic port to work in a direct current bus voltage deviation control state. x is 1, 2, 3, 4 or 5.

Further, the bus deviation control function is that if the DC bus voltage U is detected_DCLess than (100-x)% U_{DC_down}The photovoltaic port then stabilizes the DC bus voltage at (100-x)% U_{DC_down}(ii) a If the DC bus voltage U_DCHigher than x% U_{DC_up}Then the photovoltaic port stabilizes the dc bus voltage at x% U_{DC_up}。

If the DC bus voltage U_DCLess than (100-y)% U_{DC_down}Or higher than y% U_{DC_up}And then starting a fixed duty ratio control function of the photovoltaic port to control the photovoltaic port to work at a fixed duty ratio. y is 6, 7, 8, 9 or 10.

The fixed duty cycle D' calculation includes:

U_ocis the open circuit voltage at the input side of the photovoltaic port.

If the DC bus voltage U_DCLess than 90% U_{DC_down}Or greater than 10% U_{DC_up}And then, the photovoltaic port is subjected to pulse sealing control, and the photovoltaic port is controlled not to perform voltage conversion and actively output power any more.

And the communication module issues the photovoltaic port function obtained by the coordination controller through the judgment module to the photovoltaic converter so as to complete the realization of the related function.

In summary, the present invention provides a method for controlling energy flow of a photovoltaic multi-port system and a coordination controller, including: the coordination controller collects the current running information of each port, judges the running state of each port and coordinates the power; detecting and judging the range of the voltage of the direct current bus, and detecting the voltage of the direct current bus and judging the voltage range by the photovoltaic port; and photovoltaic hierarchical control, wherein different control modes are adopted by photovoltaic ports in a hierarchical manner aiming at different ranges of the voltage of the direct current bus. According to the invention, the direct current bus voltage range is divided according to the actual working conditions, and the photovoltaic port adopts different control modes aiming at each working condition, so that the system control effect can be optimized, and meanwhile, the multi-port direct current bus voltage overshoot can be quickly and effectively stabilized.

It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.