Studies on a Wind Turbine Generating System that Employs a Thyristor Inverter

Abstract

SUMMARYA new wind turbine generating system that employs a current-source thyristor inverter is proposed, and the steady-state and dynamic performances for a practical system are discussed. The proposed system is essentially based on the shaft generator system that is widely used in large ships, and it has many features such as high reliability and generation of output power of high quality. It is shown that electric power with constant frequency and voltage with low distortion can be obtained by using this novel system despite the changes in the velocity of natural wind. A dynamic model of the system is also developed, and a good agreement between simulated and experimental performances is obtained, thereby confirming the validity of the model.

Studies on a Hybrid Wind Turbine Generating System Using a Current‐Source Thyristor Inverter

“…As in the figure, jumps or sags in the inverter output line voltage waveform appear with the commutation of the inverter thyristor, and the total harmonic distortion is THD = 7.93%, which is relatively large. Although this THD is greater than 5%, which is the maximum standard value of THD when a wind turbine generator is interconnected with the grid, THD = 3.57% is obtained for the output line voltage waveform of the system, which is sufficiently small, because of the function of the duplex reactor . Furthermore, while the inverter output current becomes rectangular as shown in the figure, since the inverter is of the current‐source type, the load current is nearly sinusoidal.…”

“…Although safe commutation of the inverter becomes difficult at higher wind velocities, careful selection of in Eq. , which can be adjusted by phase control of the thyristor rectifier, but is set constant here, makes stable operation possible .…”

“…This is because currents flow automatically in the damper windings of the SG so as to cancel the harmonic components of the flux linkages of the damper windings due to the inverter output current . As a result, the armature current waveform becomes that shown in the figure , . For this reason, we must allow for the tolerance for these harmonics in the design of the SG used for the system.…”

“…. This figure consists of the simulation block diagram presented in the previous paper and an added block, the (IV) block of , which shows the system output. The dynamic response of the system can be simulated on the basis of this block diagram when wind velocity data are input.…”

“…In this paper, a novel hybrid wind turbine generating system which can resolve these issues is proposed [5][6][7][8]. This system is based on a DC-link wind turbine generating system using a current-source thyristor inverter [9], and it has many attractive features such as high reliability and high quality of electric output.…”