下面这段代码是dsp控制永磁同步电机中的PID控制，能否详细讲解一下里面的代码含义

Question

        Speed_Error=Speed_Ref - Speed_Fdb;

        Speed_Up=_IQmpy(Speed_Kp,Speed_Error);
        Speed_Ui=Speed_Ui + _IQmpy(Speed_Ki,Speed_Up) + _IQmpy(Speed_Ki,Speed_SatError);

        Speed_OutPreSat=Speed_Up+Speed_Ui;

        if(Speed_OutPreSat>Speed_OutMax)
            Speed_Out=Speed_OutMax;
        else if(Speed_OutPreSat<Speed_OutMin)
             Speed_Out=Speed_OutMin;
        else 
            Speed_Out=Speed_OutPreSat;  

        Speed_SatError=Speed_Out-Speed_OutPreSat;  

        IQ_Given=Speed_Out; 
        Speed_run=1;
    } 
    else 
    {
         SpeedLoopCount++;
    }
    if(Speed_run==1)
    {
    ialfa=ia;
    ibeta=_IQmpy(ia,_IQ(0.57735026918963))+_IQmpy(ib,_IQ(1.15470053837926));  
    //0.577=
    id = _IQmpy(ialfa,Cosine) +_IQmpy(ibeta,Sine);
    iq = _IQmpy(ibeta,Cosine)- _IQmpy(ialfa,Sine) ;



    IQ_Error=IQ_Ref-IQ_Fdb;

    IQ_Up=_IQmpy(IQ_Kp,IQ_Error);
    IQ_Ui=IQ_Ui + _IQmpy(IQ_Ki,IQ_Up) + _IQmpy(IQ_Ki,IQ_SatError);

    IQ_OutPreSat=IQ_Up+IQ_Ui;

    if(IQ_OutPreSat>IQ_OutMax)
        IQ_Out=IQ_OutMax;
    else if(IQ_OutPreSat<IQ_OutMin)
         IQ_Out=IQ_OutMin;
    else 
        IQ_Out=IQ_OutPreSat;  

    IQ_SatError=IQ_Out-IQ_OutPreSat;
    Uq=IQ_Out;


    ID_Error=ID_Ref-ID_Fdb;

    ID_Up=_IQmpy(ID_Kp,ID_Error);    
    ID_Ui=ID_Ui+_IQmpy(ID_Ki,ID_Up)+_IQmpy(ID_Ki,ID_SatError);   

    ID_OutPreSat=ID_Up+ID_Ui;    

    if(ID_OutPreSat>ID_OutMax)   
        ID_Out=ID_OutMax;
    else if(ID_OutPreSat<ID_OutMin)
         ID_Out=ID_OutMin;
    else 
        ID_Out=ID_OutPreSat;  

    ID_SatError=ID_Out-ID_OutPreSat;     
    Ud=ID_Out;

Answer 1

Speed_Error = Speed_Ref - Speed_Fdb;  //计算设定速度和反馈速度的差值

Speed_Up = _IQmpy(Speed_Kp, Speed_Error);//IQmpy是IQ lib里的乘法运算，这一步用来计算速度环比例增益和误差的乘积，即PID比例环节的结果
Speed_Ui = Speed_Ui + _IQmpy(Speed_Ki, Speed_Up) + _IQmpy(Speed_Ki, Speed_SatError);//这一步则计算积分环节的结果

Speed_OutPreSat = Speed_Up + Speed_Ui;//将比例环节和积分环节相加，获得PID的输出

if (Speed_OutPreSat > Speed_OutMax)//限幅判断，如果Speed_OutPreSat大于幅值，则Speed_Out=幅值，即Speed_OutMax
Speed_Out = Speed_OutMax;
else if (Speed_OutPreSat < Speed_OutMin)//限幅判断，如果Speed_OutPreSat小于幅值，则Speed_Out=幅值，即Speed_OutMin
    Speed_Out = Speed_OutMin;
else//如果没有超过两侧的幅度，则Speed_Out = Speed_OutPreSat
Speed_Out = Speed_OutPreSat;

Speed_SatError = Speed_Out - Speed_OutPreSat;//更新Speed_SatError以用于下一周期的积分计算

IQ_Given = Speed_Out;//将速度环的输出值设定为电机Q轴电流目标值
Speed_run = 1;//Speed_run是一个运行标志，当其非0时进行电流环计算
    }
    else
    {
    SpeedLoopCount++;//速度环计数
    }
    if (Speed_run == 1)//Speed_run是一个运行标志，当其非0时进行电流环计算
    {
        //Clark变换，把ABC三相电流转换为 α β两相电流
        ialfa = ia;
        ibeta = _IQmpy(ia, _IQ(0.57735026918963)) + _IQmpy(ib, _IQ(1.15470053837926));
        //Park变换，把α β两相电流变为dq轴电流
        id = _IQmpy(ialfa, Cosine) + _IQmpy(ibeta, Sine);
        iq = _IQmpy(ibeta, Cosine) - _IQmpy(ialfa, Sine);



        IQ_Error = IQ_Ref - IQ_Fdb;//计算Q轴电流误差

        IQ_Up = _IQmpy(IQ_Kp, IQ_Error);//电流环Q轴PID比例环节
        IQ_Ui = IQ_Ui + _IQmpy(IQ_Ki, IQ_Up) + _IQmpy(IQ_Ki, IQ_SatError);//电流环Q轴PID积分环节

        IQ_OutPreSat = IQ_Up + IQ_Ui;//电流环Q轴输出

        if (IQ_OutPreSat > IQ_OutMax)//电流环Q轴限幅判断，道理同速度环限幅
            IQ_Out = IQ_OutMax;
        else if (IQ_OutPreSat < IQ_OutMin)
            IQ_Out = IQ_OutMin;
        else
            IQ_Out = IQ_OutPreSat;

        IQ_SatError = IQ_Out - IQ_OutPreSat;//更新IQ_SatError以用于下一轮电流环积分环节计算
        Uq = IQ_Out;//更新要输出的q轴电压


        ID_Error = ID_Ref - ID_Fdb;//计算d轴电流误差

        ID_Up = _IQmpy(ID_Kp, ID_Error);//电流环d轴PID比例环节
        ID_Ui = ID_Ui + _IQmpy(ID_Ki, ID_Up) + _IQmpy(ID_Ki, ID_SatError);//电流环d轴PID积分环节

        ID_OutPreSat = ID_Up + ID_Ui;////电流环d轴PID输出

        if (ID_OutPreSat > ID_OutMax)//限幅判断
            ID_Out = ID_OutMax;
        else if (ID_OutPreSat < ID_OutMin)
            ID_Out = ID_OutMin;
        else
            ID_Out = ID_OutPreSat;

        ID_SatError = ID_Out - ID_OutPreSat;
        Ud = ID_Out;