Controller capable of achieving multi-variable controls through single-variable control unit

A controller for achieving multi-variable controls through a single-variable control unit, comprising:

• a control unit, which produces an output signal for a process according to a measured signal and a reference signal, wherein the measured signal is able to be changed;
• at least one DOF (Dynamic Offshoot Factor) unit, which receives a selection signal corresponding to a variable of the process that affects the measured signal or is affected by the control unit, and which produces a DOF signal according to short-time and long-time average values of the selection signal;
• and
• a compensation unit, which incorporates the DOF signal into one of the measured signal, the reference signal, and the output signal to obtain a respective compensation signal being sent back to the control unit, instead of the measured signal, the reference signal or the output signal, to facilitate controlling the process, wherein the DOF signal is related to an offset value between a measured value of the selection signal and an average value of the selection signal, wherein a short-time average value is obtained by taking one sample of the selection signal or by averaging S samples of the selection signal or by passing one sample of the selection signal through a first low-pass filter that has a settling time substantially the same as the time required for taking an average of the S samples of the selection signal;
• wherein a long-time average value is obtained by taking L samples of the selection signal or by passing the one sample of the selection signal through a second low-pass filter that has a settling time substantially the same as the time required for taking an average of the L samples of the selection signal;
• and wherein S is equal to or greater than 1, and L is greater than S.