Discrete-time Binary Controller using Variable-order Delta-Sigma Modulator

As a method for constructing a discrete-time binary control system, we propose a method using a variable-order delta-sigma modulator. By making the order of the modulator variable, the weaknesses of the conventional delta-sigma modulator approach can be overcome, but the dynamic switching of the order causes the modulator to become unstable. Therefore, we specified the cause of instability and showed how to overcome it. The method was applied to temperature control by zero cross-switching of AC voltage in an electric furnace with a resistant heater, and the effectiveness of the proposed method was shown.