Seoho Choi

Loss Minimizing Control of PMSM with the Use of Polynomial Approximations

Normally, look-up table based methods are being utilized for loss minimizing control of permanent magnet synchronous motors (PMSMs). But, numerous repetitive experiments are required to make a look-up table, and the program size becomes bulky. In this work, analytic methods of finding the loss minimizing solution are studied. Since the solution lies either in the interior, or on the voltage limit boundary, two different cases are dealt separately. In both cases, fourth order polynomials are derived. To obtain approximate solutions, methods of order reduction and linear approximation are utilized. The accuracies are good enough for practical use. These approximate solutions are fused into a proposed loss minimizing algorithm (LMA), and implemented in an inverter DSP. Experiments were done with the real PMSM developed for a sport-utility fuel cell electric vehicle (FCEV). The analytically derived minima were justified by experimental evidences, and the dynamic performances over wide speed range were shown to be satisfactory.

Analysis and Control of Fuel Cell Hybrid Vehicle

In order to increase efficiency of the fuel cell vehicle, it can be hybridized by using batteries or ultra-capacitors. A fuel cell vehicle model is developed and validated by comparing the simulation results with real vehicle operating results from the Hyundai Tucson fuel cell hybrid vehicle. And various types of hybridization structure are compared by simulation and the effect of component sizing is also studied. In the vehicle model, the component and controller models were developed to have modularity and integrated to have forward facing characteristics. Thus, the hybrid controller is designed and optimized by using the simulation. This paper also presents the fuel economy of the developed fuel cell hybrid vehicle when it is operated on the chassis dynamometer.Copyright