A controller achieving multi-variable control using a single-variable control unit

A controller achieving multi-variable control using a single-variable control unit includes a control unit, at least one variable, a Dynamic Offshoot Factor (DOF) unit and a compensation unit. The control unit calculates an output signal according to a measured signal and a reference signal, and the output signal is sent to a process to drive the measured signal towards the reference signal. The variable, which is measured in the process, affects the measured signal or is affected by the control unit. The DOF unit computes a DOF of the variable according to a short-term average and a long-term average of the variable. The compensation unit adds the DOF upon the measured signal, the reference signal or the output signal, and results in a compensated signal of the respective signal, which then replaces its respective signal to control the process.