Publication Date


Document Type


Committee Members

Marian Kazimierczuk (Committee Member), Kuldip Rattan (Advisor), Xiaodong Zhang (Committee Member)

Degree Name

Master of Science in Engineering (MSEgr)


High power silicon controlled rectifiers (SCR) are used in the application of infrared radiation testing. A case study has been performed on a department of defense facility utilizing SCRs to transfer electrical energy to thermal energy. The facility is capable of generating up to 5000 °F across large cross-sectional areas, requiring tens of megawatts of power. The combination of high power, unbalanced loads, and SCR switching generate high harmonic disturbances that offer significant challenges for conventional linear control systems. In addition, unbalanced three-phase distribution systems are difficult to model, specifically during switching transients. Fuzzy logic is used to characterize the non-linear plant dynamics, control the system output, and reduce harmonics. Although the use of fuzzy logic for harmonic reduction has been used extensively in the power industry, most applications focus on compensating for harmonic disturbance rather than avoiding it. Harmonic compensation adds hardware in the system, which adds maintenance costs and inefficiency. This thesis introduces a technique to eliminate harmonic content in the control loop without adding additional hardware. A simulation of the system was created and fuzzy logic was used to characterize the behavior of the simulation. The simulation results demonstrated the non-linear control problem and identified key harmonic areas to avoid. A fuzzy proportional-integral controller along with a fuzzy harmonic reduction controller is implemented in this thesis to improve the control response while avoiding harmful harmonic interference. The fuzzy harmonic reduction controller yielded a hybrid pulse width modulation output that eliminated the most harmful harmonics while maintaining closed loop control.

Page Count


Department or Program

Department of Electrical Engineering

Year Degree Awarded