阅读说明：本技术 一种单级多输入并网逆变器的控制装置及系统 (Control device and system of single-stage multi-input grid-connected inverter ) 是由 曾汉超 邱琰辉 张达敏 张强 于 2020-05-29 设计创作，主要内容包括：本发明提供了一种单级多输入并网逆变器的控制装置及系统,通过MPPT控制器采集输入源的输入电流,生成最大功率点电流,发送至对应的运算节点和PI调节器生成对应的误差放大信号,DSP控制器接收每一调制电路的误差放大信号,并进行求和运算后发送至第一调制电路的第二运算节点,第一调制电路根据和值生成并网电流基准信号,电流调节器根据反馈信号及基准信号生成第一调制信号,多路第二调制电路直接将第二误差放大信号与电网电压正弦同步信号相乘得到第二调制信号,逻辑电路根据第一调制信号及第二调制信号生成控制信号发送至逆变器,实现了对并网电流的直接控制,保证了并网电流的波形质量,提高了逆变器的动态性能和抗干扰能力。(The invention provides a control device and a system of a single-stage multi-input grid-connected inverter, which collect input current of an input source through an MPPT controller to generate maximum power point current, send the maximum power point current to a corresponding operation node and a PI regulator to generate a corresponding error amplification signal, a DSP controller receives the error amplification signal of each modulation circuit, performs summation operation and then sends the error amplification signal to a second operation node of a first modulation circuit, the first modulation circuit generates a grid-connected current reference signal according to the sum, a current regulator generates a first modulation signal according to a feedback signal and the reference signal, a multi-path second modulation circuit directly multiplies the second error amplification signal by a grid voltage sine synchronous signal to obtain a second modulation signal, a logic circuit generates a control signal according to the first modulation signal and the second modulation signal and sends the control signal to the inverter, thereby realizing the direct control of the grid-connected current, the waveform quality of grid-connected current is ensured, and the dynamic performance and the anti-interference capability of the inverter are improved.)

1. A control device of a single-stage multi-input grid-connected inverter is characterized by comprising: first modulation circuit, multichannel second modulation circuit and logic circuit, wherein:

the first modulation circuit comprises a first MPPT controller, a first operation node, a first PI regulator, a second operation node, a third operation node, a fourth operation node and a current regulator which are connected in sequence;

the first MPPT controller is used for acquiring a first output current of a current input source and generating a first maximum power point current according to the first output current;

the first operation node is used for operating the first output current and the first maximum power point current and sending an operation result to the first PI regulator;

the first PI regulator is used for amplifying the operation result and generating a first error amplification signal;

the second operation node is configured to receive a plurality of second error amplified signals of the second modulation circuits, and send the first error amplified signal and the plurality of second error amplified signals to a third operation node;

the third operation node is used for receiving the first error amplification signal and the plurality of second error amplification signals and calculating to generate a reference signal of grid-connected current;

the fourth operation node is used for receiving a feedback signal of grid-connected current and a reference signal of the grid-connected current and sending the feedback signal and the reference signal to the current regulator;

the current regulator is used for generating a first modulation signal according to the feedback signal of the grid-connected current and the reference signal of the grid-connected current;

and the logic circuit is used for receiving the first modulation signal and a plurality of paths of second modulation signals generated by the second modulation circuit, generating a control signal and sending the control signal to the inverter.

2. The control device of a single-stage multi-input grid-connected inverter according to claim 1, wherein the first operation node is configured to operate the first output current and the first maximum power point current, and send an operation result to the first PI regulator, specifically:

and carrying out difference operation on the first maximum power point current and the first output current, and sending a difference value to the PI regulator.

3. The control device of a single-stage multi-input grid-connected inverter according to claim 1, wherein the third operation node is configured to receive the first error amplification signal and the plurality of second error amplification signals, and calculate to generate a reference signal of a grid-connected current, and specifically:

and the third operation node receives the sum of the first error amplification signal and the plurality of second error amplification signals, and multiplies the sum by the grid voltage sinusoidal synchronous signal to obtain the reference signal of the grid-connected current.

4. The control device of the single-stage multi-input grid-connected inverter according to claim 1, wherein the second modulation circuit comprises a second MPPT controller, a fifth operation node, a second PI regulator, and a sixth operation node, which are connected in sequence, wherein:

the second MPPT controller is used for receiving a second input current of a current input source and generating a second maximum power point current according to the second output current;

the fifth operation node is used for carrying out difference on the second output current and the second maximum power point current, and the difference value is sent to the second PI regulator;

the second PI regulator is used for amplifying the difference value to generate a second error amplification signal;

and the sixth operation node is used for receiving the power grid voltage sine synchronous signal and multiplying the second error amplification signal by the power grid voltage sine synchronous signal to obtain a second modulation signal.

5. A control system of a single-stage multi-input grid-connected inverter is characterized by comprising a DSP controller and a control device of the single-stage multi-input grid-connected inverter according to any one of claims 1 to 4, wherein the DSP controller is connected with the first modulation circuit and the second modulation circuit;

the DSP controller receives the first error amplification signal and the plurality of second error amplification signals, sums the first error amplification signal and the plurality of second error amplification signals, and sends the sum to the second operation node, and the DSP controller receives a feedback signal of grid-connected current and sends the feedback signal to the fourth operation node.

Technical Field

The invention relates to the field of power electronics, in particular to a control device and a control system of a single-stage multi-input grid-connected inverter.

Background

The single new energy power generation systems such as photovoltaic cells and wind power generators generally have the defects of unstable and discontinuous power supply, change along with weather conditions and the like, and the power generation quality and efficiency are seriously influenced. In order to improve the power generation quality and efficiency, a distributed power generation system adopting a plurality of new energy sources for combined power supply is required. The single-stage multi-input grid-connected inverter can directly convert energy of a plurality of same or different new energy sources into low-frequency alternating current to feed into an alternating current power grid, has the advantages of simple circuit structure, single-stage power conversion, high conversion efficiency and the like, and has important theoretical and application values in distributed power generation occasions of combined power supply of a plurality of new energy sources. The circuit structure of the single-stage multi-input grid-connected inverter is shown in fig. 1.

Currently, a single-stage multi-input grid-connected inverter generally adopts a maximum power output control method, as shown in fig. 2. The control idea is as follows: the 1 st, 2 nd, … th and n-th input sources all output to an alternating current power grid at the maximum power; when the voltage (current) of the n-path input source is fixed, the input power can be controlled as long as the current (voltage) is controlled, and therefore the grid-connected power is controlled.

The single-stage multi-input grid-connected inverter adopting the input power control method realizes the maximum power output of a plurality of new energy sources, but has an obvious defect that: because the grid-connected current iL or the filter inductor current iLf is not controlled (note: iL is iLf), the grid-connected current waveform quality is poor, and because the response speed of the MPPT loop is slow, when external conditions such as illumination intensity or wind speed and the like suddenly change, the fast response of the grid-connected current cannot be caused, so that the power is instantaneously unbalanced, the grid-connected current is distorted, and the inverter is damaged. Therefore, the single-stage multi-input grid-connected inverter adopting the control method has poor dynamic performance and weak anti-interference capability, and the practicability is greatly limited.

Disclosure of Invention

The invention discloses a control device and a control system of a single-stage multi-input grid-connected inverter, which aim to realize the direct control of grid-connected current, ensure the waveform quality of the grid-connected current and improve the dynamic performance and the anti-interference capability of the inverter.

A first embodiment of the present invention provides a control apparatus for a single-stage multiple-input grid-connected inverter, including: first modulation circuit, multichannel second modulation circuit and logic circuit, wherein:

the first modulation circuit comprises a first MPPT controller, a first operation node, a first PI regulator, a second operation node, a third operation node, a fourth operation node and a current regulator which are connected in sequence;

the first MPPT controller is used for acquiring a first output current of a current input source and generating a first maximum power point current according to the first output current;

the first operation node is used for operating the first output current and the first maximum power point current and sending an operation result to the first PI regulator;

the first PI regulator is used for amplifying the operation result and generating a first error amplification signal;

the second operation node is configured to receive a plurality of second error amplified signals of the second modulation circuits, and send the first error amplified signal and the plurality of second error amplified signals to a third operation node;

the third operation node is used for receiving the first error amplification signal and the plurality of second error amplification signals and calculating to generate a reference signal of grid-connected current;

the fourth operation node is used for receiving a feedback signal of grid-connected current and a reference signal of the grid-connected current and sending the feedback signal and the reference signal to the current regulator;

the current regulator is used for generating a first modulation signal according to the feedback signal of the grid-connected current and the reference signal of the grid-connected current;

and the logic circuit is used for receiving the first modulation signal and a plurality of paths of second modulation signals generated by the second modulation circuit, generating a control signal and sending the control signal to the inverter.

Preferably, the first operation node is configured to operate the first output current and the first maximum power point current, and send an operation result to the first PI regulator, specifically:

and carrying out difference operation on the first maximum power point current and the first output current, and sending a difference value to the PI regulator.

Preferably, the third operation node is configured to receive the first error amplified signal and the plurality of second error amplified signals, and calculate to generate a reference signal of the grid-connected current, specifically:

and the third operation node receives the sum of the first error amplification signal and the plurality of second error amplification signals, and multiplies the sum by the grid voltage sinusoidal synchronous signal to obtain the reference signal of the grid-connected current.

Preferably, the second modulation circuit includes a second MPPT controller, a fifth operation node, a second PI regulator, and a sixth operation node connected in sequence, wherein:

the second MPPT controller is used for receiving a second input current of a current input source and generating a second maximum power point current according to the second output current;

the fifth operation node is used for carrying out difference on the second output current and the second maximum power point current, and the difference value is sent to the second PI regulator;

the second PI regulator is used for amplifying the difference value to generate a second error amplification signal;

and the sixth operation node is used for receiving the power grid voltage sine synchronous signal and multiplying the second error amplification signal by the power grid voltage sine synchronous signal to obtain a second modulation signal.

The second embodiment of the invention provides a control system of a single-stage multi-input grid-connected inverter, which comprises a DSP controller and a control device of the single-stage multi-input grid-connected inverter, wherein the DSP controller is connected with the first modulation circuit and the second modulation circuit;

the DSP controller receives the first error amplification signal and the plurality of second error amplification signals, sums the first error amplification signal and the plurality of second error amplification signals, and sends the sum to the second operation node, and the DSP controller receives a feedback signal of grid-connected current and sends the feedback signal to the fourth operation node.

Based on the control device and the system of the single-stage multi-input grid-connected inverter provided by the invention, the MPPT controller is used for collecting the input current of each input source, generating the maximum power point current, sending the maximum power point current to the corresponding operation node and the PI regulator to generate the corresponding error amplification signal, the DSP controller is used for receiving the error amplification signal of each modulation circuit, carrying out summation operation and then sending the error amplification signal to the second operation node of the first modulation circuit, the first modulation circuit generates a grid-connected current reference signal according to the sum value, the DSP controller is used for sending the grid-connected current feedback signal to the fourth operation node, the current regulator generates a first modulation signal according to the feedback signal and the reference signal, a plurality of second modulation circuits directly multiply the second error amplification signal with the grid voltage sinusoidal synchronous signal to obtain a second modulation signal, the logic circuit generates a control signal according to the first modulation signal and the second modulation signal and sends the control signal to the inverter, the direct control of the grid-connected current is realized, the waveform quality of the grid-connected current is ensured, and the dynamic performance and the anti-interference capability of the inverter are improved.

Drawings

Fig. 1 is a schematic circuit structure diagram of a single-stage multi-input grid-connected inverter provided in the background art;

fig. 2 is a schematic diagram of a maximum power output control device of a single-stage multi-input grid-connected inverter provided in the background art;

fig. 3 is a schematic diagram of a control device of a single-stage multi-input grid-connected inverter provided by the invention;

fig. 4 is a waveform of grid-connected current when the grid-connected current is suddenly changed under the control device of the single-stage multi-input grid-connected inverter provided by the invention;

fig. 5 is an expanded waveform of grid-connected current when the grid-connected current suddenly changes under the control device of the single-stage multi-input grid-connected inverter provided by the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

For better understanding of the technical solutions of the present invention, the following detailed descriptions of the embodiments of the present invention are provided with reference to the accompanying drawings.

It should be understood that the described embodiments are only some embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrases "if determined" or "if detected (a stated condition or event)" may be interpreted as "when determined" or "in response to a determination" or "when detected (a stated condition or event)" or "in response to a detection (a stated condition or event)", depending on the context.