INTRODUCTION OF POWER ELECTRONICS TO ELECTRIC MACHINES LAB Swakshar Ray, Seungwon An, Thomas W. Gedra School of Electrical & Computer Engineering, Oklahoma State University, Stillwater OK, 74078 ABSTRACT This paper presents a proposal for a new upgrade that will incorpo- rate power electronics experiments in the electric machines lab at Oklahoma State University (both Stillwater and Tulsa campuses). We will introduce a general lab setup which includes digital data acquisition (DAQ) and virtual instrumentation. The application of 3 inverters will be discussed with our lab setup. The installation of flexible AC transmission system (FACTS) devices in our 3-bus power system will be presented. In addition, a modelling of uni- fied power flow controller (UPFC) for the use of optimal power flow (OPF) will be described. 1. INTRODUCTION Well-established power system labs have been introduced in sev- eral educational institutes [1, 2]. However, they are used for demon- stration purposes for undergraduate students, and student’s involve- ment is limited due to safety concerns and complicated system configurations [1]. In addition, since the installation of the power system lab is costly and requires large space, most engineering schools are not capable of implementing a power system lab [3]. As an alternative, a simulation and virtual learning system were presented in [3]. Even though they give a good insight to stu- dents on power systems, their applications are strictly limited since all possible dynamics of power systems can not be expressed. As a solution to the above problems, we have started the mod- ification of the electric machines lab at OSU-Stillwater in the sum- mer 1996, and completed the first-phase of the prototype lab in 1997 [4, 5, 6]. As a key feature, we introduced a digital data acquisition (DAQ), data processing and graphical interface using LabVIEW virtual instrumentation. Since then, energy conversion and power system operation experiments were unified in a single laboratory. Even though power electronics is a part of power sys- tems, due to the unavailability of the required setup, it is difficult to perform experiments relating power electronics to power sys- tems and energy conversions. In modern facilities of energy con- version and power systems, use of power electronics devices is becoming inevitable. They make control of power flow easier and faster, which allows a better use of existing facilities such as power plants and transmission lines. Noticing this problem, we have de- vised a proposal to incorporate modern power electronics devices in the second-phase lab design. This paper proposes new power electronics experiments that can be conducted with our unique lab setup. 2. GENERAL LAB SETUP There are four benches in Stillwater, and two nearly completed in Tulsa. Each bench consists of front panels, a prime mover/dynamoter with a motor mount, and a computer as shown in figure 1. The benches are 71” wide and 37” high from the benchtop so that stu- dents can easily access all the equipment. Each bench can be used - + CD DRIVE 52Xmx Figure 1: Front View of Experimental Bench. independently for an energy conversion lab, a power electronics lab, or interconnected for power system operations. Figure 1 also shows the enlarged view of the power electronics panel, which will be used for AC-DC converters, 3 inverters and FACTS devices. We use fractional-horsepower machines with wiring jacks lo- cated on machine front panel. To perform various experiments and measure torque, power and speed, the rotating machines can be coupled with Lab-Volt Prime Mover/Dynamometer (Model 8960- 10). All four Stillwater and the two Tulsa experimental benches are equipped with a DAQ and signal conditioning systems, as shown in figure 2, and the system inside the dotted lines is under de- velopment for new power electronics experiments. Tulsa has 7 voltage and 7 current channels, and the data acquired by those channels are fed to the LabVIEW, while Stillwater has only 4 each (to be upgraded to 7). We use LabVIEW virtual instrumentation, which is a powerful and flexible tool for data acquisition, process- ing, graphical interface, and control of external processes in real time. LabVIEW can also communicate with GPIB instruments such that the powerful processing and display capabilities of Lab- VIEW can combine with the special capabilities of GPIB instru- ments. For pulse width modulation (PWM) inverters with high fre- quency switching applications, we will use the GPIB oscilloscope