Design PID Controllers for Three-Phase Rectifier using Closed-Loop PID Autotuner Block

此示例使用：

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This example shows how to use the Closed-Loop PID Autotuner block to tune the DC-link voltage, DQ axis current, and voltage neutral controllers for a Vienna-rectifier-based power factor corrector.

Power Factor Correction Model

该示例使用所描述的功率因数校正电路维也纳整流器控制(Simscape Electrical)。功率因数校正预压器校正负载功率因数，从而提高了分配系统的能效。当非线性阻抗（例如开关模式电源）连接到AC电网时，该校正是有用的。

该模型使用维也纳整流器和开关模式电源来将三相120V的AC电源转换为调节的400V直流电源。为确保设备在电阻被正确表示，半导体元件使用MOSFET而不是理想的开关进行建模。模型仿真配置为使用分区求解器在加速器模式下运行。

Open_System（'PWM_Rectifier_Vienna_SC')

DQ轴电流控制

对于此示例，维也纳整流器的DQ轴控制器如下图所示建模。

在DQ轴控制中，使用投影将时间相关的三相电流转换为时间不变的双坐标向量。这些变换是Clarke转换，公园变换及其各自的逆变换。这些变换在测量子系统内实现为块。为了保持接近1的功率因数，从网格中汲取的无功功率应接近零。因此，命令从控制器的零Q轴电流允许功率因数接近1。

在该模型中，控制器具有以下增益：

DC-link voltage PI controller: P = 2 and I = 20
Both DQ-axis current PI controllers: P = 5 and I = 500
Voltage neutral P controller: P = 0.001

The controller gains are stored in a Data Store Memory block and provided externally to each PID block. When the tuning process for a controller is complete, the new tuned gains are written to the Data Store Memory block. This configuration allows you to update your controller gains in real-time during the simulation.

对于此示例，您使用闭环PID自动箱块重新定位这些控制器。

闭环PID自动箱块

闭环PID自动箱块允许您一次调整一个PID控制器。它在植物输入中注射了正弦扰动信号，并在闭环实验期间测量所得到的植物输出。当实验停止时，块基于在近期所需带宽附近的少量点估计的工厂频率响应来计算PID增益。对于该维也纳整流器模型，闭环PID自动箱块可用于每个控制器，如下面的DC链路电压环所示。

当您使用闭环PID AutoTuner块具有初始控制器时，此工作流程适用。这种方法的好处是：

If there is an unexpected disturbance during the experiment, it is rejected by the existing controller to ensure safe operation.
通过抑制扰动信号，现有控制器将工厂保持在其标称操作点附近运行。

使用闭环PID自动箱块进行模拟和实时应用程序：

The plant must be either asymptotically stable (all the poles are strictly stable) or integrating. The autotuner block does not work with an unstable plant.
具有现有控制器的反馈循环必须稳定。
为了实时准确地估计植物频率响应，在实验期间最小化维也纳整流器模型中的任何干扰的发生。AutoTuner块希望工厂输出仅响应注入的扰动信号。
Because the feedback loop is closed during the experiment, the existing controller suppresses the injected perturbation signals as well, which reduces the accuracy of frequency response estimation when your target bandwidth is far away from the current bandwidth.

调整Cascaded Feedback Loops

由于闭环PID AutoTuner块一次仅调整一个PID控制器，因此必须在模型中单独调整四个控制器。因此，您首先调整内部电流控制器，然后是DC-Link电压控制器，然后是电压中性控制器。

During the model simulation:

The D-axis current controller is tuned between 0.65 and 0.75 sec.
The Q-axis current controller is tuned between 0.8 and 0.9 sec.
DC-Link电压控制器在0.95和1.45秒之间进行调谐。
The voltage neutral controller is tuned between 1.7 and 1.72 sec.

After tuning each of the controllers, the controller gains are updated through the Data Store Memory block.

Configure Autotuner Block

使用工厂和PID块连接闭环PID自动箱块后，为每个设备配置调谐和实验设置。在这一点调整tab, there are two main tuning settings:

目标带宽- 确定您希望控制器响应的速度快。在此示例中，为电流控制的3000 rad / sec选择3000 rad / sec，用于DC-Link电压控制，20000 RAD / S，用于电压中性控制。

目标阶段保证金- 确定您希望控制器的强大程度如何。在此示例中，为所有控制器选择60度。

在这一点实验tab, there are three main experiment settings:

植物类型- Specifies whether the plant is asymptotically stable or integrating. In this example, the Vienna rectifier model is stable.
Plant Sign- Specifies whether the plant has a positive or negative sign. The plant sign is positive if a positive change in the plant input at the nominal operating point results in a positive change in the plant output when the plant reaches a new steady state. Otherwise, the plant sign is negative. If a plant is stable, the plant sign is equivalent to the sign of its DC gain. If a plant is integrating, the plant sign is positive (or negative) if the plant output keeps increasing (or decreasing). In this example, the Vienna rectifier model has a positive plant sign.
Sine Amplitudes- 指定注入的正弦波的幅度。在这个例子中，为了确保工厂在饱和度限制内恰当兴奋，请选择0.6for the D-axis controller,0.19for the Q-axis controller,1对于DC-Link电压控制器，和0.01对于电压中性控制器。如果激励幅度要么太大或太小，则会产生这些实验的不准确的频率响应估计结果。

在Accelerator模式下模拟AutoTuner块

在此示例中，维也纳整流器模型在加速器模式下运行，并且在一次模拟中调整所有四个控制器。由于电力电子控制器的示例时间小，模型的仿真通常需要几分钟。

To tune the controllers, simulate the model.

sim('PWM_Rectifier_Vienna_SC')

ans = 金宝appsimulink.simulationOutput：logsout：[1x1 simulink.simulationData.dataset] tout：[4000001x1双]仿真metaData：[1x1 simulink.simulationmetadata] errormessage：[0x0 char]

The graph below shows the DC-link voltage profile during the current and voltage controller tuning from 0.65 to 1.45 seconds. It also shows the introduction of an unbalanced load at 1.5 seconds and the subsequent voltage neutral controller tuning at 1.7 seconds.

Open_System（'pwm_rectifier_vienna_sc / scopes / scope')

四个控制器用新的收益调整。

DC-link voltage PI controller: P = 0.7386 and I = 135.6
D轴电流PI控制器：P = 8.407和i = 1127
Q轴电流PI控制器：P = 11.91和i = 3706
Voltage neutral P controller: P = 6.628

The graph below shows the DC-link voltage response in comparison to the reference before and after tuning the controllers. The original controller (red) is unable to maintain the DC-link voltage after the introduction of unbalanced loads at 0.7 and 1.1 seconds. On the other hand, the autotuned controller decreases the rise time with minimal overshoot and a good settling time to the steady-state value.