阅读说明：本技术 四桥臂逆变器的电能质量控制方法及其内嵌式重复控制器 (Electric energy quality control method of four-bridge arm inverter and embedded repetitive controller thereof ) 是由 王金录 于 2019-12-23 设计创作，主要内容包括：本发明公开了一种内嵌式重复控制器,采用奇次谐波重复控制器或偶次谐波重复控制器进行重复控制。该内嵌式重复控制器能够有效地降低数据存储量和处理量,与现有PID控制器共同作用,不仅能够有效的抑制各次谐波的扰动,而且可以弥补重复控制本身动态响应能力不足的问题。本发明还提供一种四桥臂逆变器的电能质量控制方法。(The invention discloses an embedded repetitive controller, which adopts an odd harmonic repetitive controller or an even harmonic repetitive controller to carry out repetitive control. The embedded repetitive controller can effectively reduce data storage capacity and processing capacity, and not only can effectively inhibit disturbance of each harmonic wave but also can make up the problem of insufficient dynamic response capability of repetitive control under the combined action of the embedded repetitive controller and the existing PID controller. The invention also provides a power quality control method of the four-bridge arm inverter.)

1. An embedded repetitive controller is characterized in that an odd harmonic repetitive controller or an even harmonic repetitive controller is adopted for repetitive control, wherein

The mathematical internal model of the odd harmonic repetition controller in the discrete form is as follows:

the mathematical internal model of the odd harmonic repetition controller in the discrete form is as follows:

in the formulae (1) and (2),

2. The in-line repetition controller of claim 1, wherein the discrete transfer function of the odd harmonic repetition controller is as follows:

in the formula (3), the reaction mixture is,

3. The embedded repetitive controller of claim 2, wherein if an odd-harmonic repetitive controller is adopted, the output y (z) of the embedded repetitive controller and the reference r (z) satisfy the following formula:

（4）；

and the output quantity Y (z) and the disturbance quantity D (z) satisfy the following formula:

in the formulae (4) and (5),

the stability of the embedded repetitive controller needs to meet the following conditions:

condition 1: the embedded repetitive controller is a stable system under the condition of not considering the odd harmonic repetitive controller;

condition 2: the following formula is satisfied:

4. the in-line repetitive controller of claim 1, wherein the discrete transfer function of the even harmonic repetitive controller is as follows:

in the formula (4), the reaction mixture is,

5. The embedded repetitive controller of claim 4, wherein if an even harmonic repetitive controller is adopted, the output Y (z) of the embedded repetitive controller and the reference R (z) satisfy the following formula:

and the output quantity Y (z) and the disturbance quantity D (z) satisfy the following formula:

in the formulae (7) and (8),

the stability of the embedded repetitive controller needs to meet the following conditions:

condition 1: the embedded repetitive controller is a stable system under the condition of not considering the even harmonic repetitive controller;

condition 2: the following formula is satisfied:

6. the inline repetition controller of claim 3 or 5, further characterized in that the closed loop transfer function of the inline repetition controller without regard to repetition control is as follows:

（9）。

7. the electric energy quality repetitive control method of the four-bridge arm inverter is characterized in that under a synchronous rotation coordinate system dq0, a current-voltage double closed-loop control system is adopted to control a d-axis signal, a q-axis signal and a 0-axis signal output by the four-bridge arm inverter; the voltage outer ring of the d-axis decoupling and/or q-axis structure of the current-voltage double closed-loop control system adopts the embedded repetitive controller adopting the odd harmonic repetitive controller in any one of claims 1 to 3 and 6, and/or the voltage outer ring of the 0-axis decoupling of the current-voltage double closed-loop control system adopts the embedded repetitive controller adopting the even harmonic repetitive controller in any one of claims 1 and 4 to 6.

8. The repetitive power quality control method for the four-leg inverter according to claim 7, wherein the current-voltage double closed-loop control system comprises:

under the condition of not considering the action of the embedded repetitive controller, designing PID controller parameters in the current-voltage double closed-loop control system in a continuous time domain, and ensuring that the current-voltage double closed-loop control system has larger relative stability margin and good dynamic characteristics;

discretizing the system model designed in the previous step, introducing the discretized system model into the embedded repetitive controller, and designing parameters of the embedded repetitive controller on the premise of ensuring the stability of the current-voltage double closed-loop control system.

Technical Field

The invention relates to an inverter control technology, in particular to a power quality control method of a four-leg inverter and an embedded repetitive controller thereof.

Background

As an important carrier for the application of distributed power generation technology, micro-grid technology has received much attention. The three-phase inverter is used as a key interface circuit in the microgrid and plays a decisive role in the power quality of the microgrid. However, as the complexity of the load increases, the unbalanced load and the nonlinear load in the microgrid may adversely affect the waveform quality of the output voltage of the three-phase inverter, causing a three-phase voltage imbalance problem and a voltage distortion problem.

For a four-leg inverter under a synchronous rotating coordinate system, no matter unbalanced load or nonlinear load, disturbance which changes in a sine rule is generated in output voltage. In order to improve the voltage output characteristics of the four-leg inverter under the load condition, the four-leg inverter is required to be connected with a power supplyThe angle of the control system is taken into consideration, and the suppression capability of the four-bridge arm inverter on voltage disturbance caused by a load is improved. The traditional PID controller has poor inhibition effect on disturbance signals with sine regular change, while the existing repetitive controller has high-precision steady-state characteristic and can solve the problem that the periodic disturbance signals introduced by the load in a control system have insufficient inhibition capability, but the existing repetitive controller adopts a digital internal model

According to the amplitude-frequency characteristic, the gain of the existing repetitive controller at the fundamental frequency and all sub-multiples (below the Nyquist frequency) of an error signal is infinite, and the amplitude-frequency characteristic ensures that the existing repetitive controller can perform non-static tracking on all odd-even sub-harmonics below the Neissian frequency, but 2N data storage units in the repetitive controller are occupied, and a large amount of data storage and processing are occupied.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides an embedded repetitive controller which can effectively reduce data storage capacity and processing capacity, and can effectively inhibit the disturbance of each subharmonic and make up the problem of insufficient dynamic response capability of repetitive control under the combined action of the embedded repetitive controller and the existing PID controller.

The invention also provides a power quality control method of the four-bridge arm inverter.

The technical problem to be solved by the invention is realized by the following technical scheme:

an embedded repetitive controller adopts an odd harmonic repetitive controller or an even harmonic repetitive controller for repetitive control, wherein

The mathematical internal model of the odd harmonic repetition controller in the discrete form is as follows:

（1）；

the mathematical internal model of the odd harmonic repetition controller in the discrete form is as follows:

（2）；

in the formulae (1) and (2),is the frequency of the fundamental wave and is,

in order to be able to sample the frequency,

is the number of samples per fundamental period.

Further, the discrete transfer function of the odd harmonic repetition controller is as follows:

（3）；

in the formula (3), the reaction mixture is,

in order to repeatedly control the amount of gain,

in order to be a low-pass filtering model,

a phase lead compensation model.

Further, if an odd harmonic repetitive controller is adopted, the output y (z) of the embedded repetitive controller and the reference r (z) satisfy the following formula:

（4）；

and the output quantity Y (z) and the disturbance quantity D (z) satisfy the following formula:

（5）；

in the formulae (4) and (5),

in order to be a PID control model,

is a system model of the controlled object that,

a closed loop transfer function for the inline repetition controller without regard to the odd harmonic repetition controller;

the stability of the embedded repetitive controller needs to meet the following conditions:

condition 1: the embedded repetitive controller is a stable system under the condition of not considering the odd harmonic repetitive controller;

condition 2: the following formula is satisfied:

。

further, the discrete transfer function of the even harmonic repetition controller is as follows:

（6）；

in the formula (4), the reaction mixture is,

in order to repeatedly control the amount of gain,in order to be a low-pass filtering model,

a phase lead compensation model.

Further, if an even harmonic repetitive controller is adopted, the output y (z) of the embedded repetitive controller and the reference r (z) satisfy the following formula:

（7）；

and the output quantity Y (z) and the disturbance quantity D (z) satisfy the following formula:

（8）；

in the formulae (7) and (8),

in order to be a PID control model,

is a system model of the controlled object that,

a closed loop transfer function for the inline repetition controller without regard to the even harmonic repetition controller;

the stability of the embedded repetitive controller needs to meet the following conditions:

condition 1: the embedded repetitive controller is a stable system under the condition of not considering the even harmonic repetitive controller;

condition 2: the following formula is satisfied:

。

further, the closed loop transfer function of the embedded repetitive controller without considering the repetitive control is as follows:

（9）。

a method for repeatedly controlling the power quality of a four-bridge arm inverter is characterized in that under a synchronous rotation coordinate system dq0, as shown in fig. 3, a current-voltage double closed-loop control system is adopted to control a d-axis signal, a q-axis signal and a 0-axis signal output by the four-bridge arm inverter; the voltage outer ring of the d-axis decoupling and/or q-axis structure of the current-voltage double closed-loop control system adopts the embedded repetitive controller adopting the odd harmonic repetitive controller, and/or the voltage outer ring of the 0-axis decoupling of the current-voltage double closed-loop control system adopts the embedded repetitive controller adopting the even harmonic repetitive controller.

Further, the current-voltage double closed-loop control system comprises:

under the condition of not considering the action of the embedded repetitive controller, designing PID controller parameters in the current-voltage double closed-loop control system in a continuous time domain, and ensuring that the current-voltage double closed-loop control system has larger relative stability margin and good dynamic characteristics;

discretizing the system model designed in the previous step, introducing the discretized system model into the embedded repetitive controller, and designing parameters of the embedded repetitive controller on the premise of ensuring the stability of the current-voltage double closed-loop control system.

The invention has the following beneficial effects:

compared with the existing repetitive controller, the odd harmonic repetitive controller and the even harmonic repetitive controller only need to occupy half of the storage space of data amount in the implementation process of the algorithm, and the operation amount is also reduced by half, so that the data storage amount and the processing amount can be effectively reduced.

According to the scheme, the odd harmonic repetitive controller is adopted to control d-axis signals and q-axis signals of the four-bridge arm inverter, the even harmonic repetitive controller is adopted to control 0-axis signals of the four-bridge arm inverter, and the even harmonic repetitive controller and the existing PID controller act together, so that not only can disturbance of each harmonic be effectively inhibited, but also the problem of insufficient dynamic response capability of repetitive control can be solved.

Drawings

FIG. 1 is a diagram of an embedded repetitive controller of an odd harmonic repetitive controller according to the present invention;

FIG. 2 is a diagram of an embedded repetitive controller of an even harmonic repetitive controller according to the present invention;

fig. 3 is an architecture diagram of a power quality control system of a four-leg inverter according to the present invention.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and examples.