Prospect of new pumped-storage power station

In this paper, a new type of pumped-storage power station with faster response speed, wider regulation range, and better stability is proposed. The operational flexible of the traditional pumped-storage power station can be improved with variable-speed pumped-storage tech no logy. Combined with chemical en ergy storage, the failure to achieve sec on d-order response speed and the insufficient safety and reliability of pumped-storage power units could be solved. With the better solar en ergy and site resources, the in teg rated performance can be improved by an optical storage system in stalled in future pumped-storage stations. Through the characteristics analysis of the new type of pumped-storage power station, three types of optimal station locations are proposed, namely, the load concentration area, new energy concentration area, and ultrahigh- voltage direct current receiver area. Taking the new pumped-storage power station as an example, the advantages of multi-energy cooperation and joint operation are analyzed. It can be predicted that the frequency and load regulation of the power grid will be more flexible, and the service capacity to the main power grid will be much stronger in the future.

A sensorless efficiency test system for a high-speed permanent magnet synchronous motor

We present a sensorless efficiency test system with energy recovery for a high-speed permanent magnet synchronous motor(PMSM). In the system, two identical high-speed PMSMs are used as the motor under test(MUT)and the load machine(LM),respectively.A new sensorless vector control(VC) method based on a hypothetical reference frame is presented to control both the MUT and the LM.Also,a regenerating unit is used to implement energy circulation to save energy.Experiments were carried out on a prototype, with a digital controller based on the TMS320 F28335, to verify the adequacy of the sensorless VC method.As a result,the efficiency test system achieves the load test at the speed of 21000 r/min without any reduction equipment. During the test, the energy regenerated by the LM could be fed back to the MUT by the regenerating unit, and 81.31% electrical power was saved.In addition, with the proposed sensorless VC method,both the MUT and the LM can work at i_d = 0 without a position sensor.