Characteristics and Current Harmonic Control of N* Three-Phase PMSG for HVDC Transmission Based on MMC

Abstract

The permanent magnet synchronous generator (PMSG) is widely used in high voltage DC transmission technology of wind power systems due to its high-power density, high reliability and simple maintenance. To meet the increasing rated power of the generator (≥10 MW), the multi-converter parallel connection is usually used, which significantly increases the complexity and cost of the system. Therefore, a new modular N* three-phase PMSG is proposed in this paper. Based on the structure and working principle of the generator, the finite element model is established, and the electromagnetic properties are obtained by finite element analysis. Aiming at the unique winding structure and characteristics of modular N* three-phase PMSG, a generator side current converter harmonic control algorithm, combining a resonant controller with the proportional-integral regulator, is proposed. The suppression of stator current harmonics at different speeds could be achieved by the proposed algorithm, and the efficiency of the wind power generation system can be improved. Finally, the feasibility of the novel generator and the effectiveness of the proposed algorithm are verified by simulation and experiment.

Predictive Power Control of Novel N*3-phase PM Energy Storage Motor for Urban Rail Transit

“…Figure 4 shows torque curve of 3*3-phase PM energy storage motor. The characteristics of 6*3-phase PM energy storage motor are as follow [10]:…”

“…According to the characteristics analysis of the N*3-phase PM energy storage motor, the d-and q-axis voltage equations of N*3-phase PM energy storage motor can be obtained as follows [10,16]:…”

“…The structural diagram of the 6*3-phase PM energy storage motor system with PPC strategy is shown in Figure 8. According to Figure 8, the operating principle of the 6*3-phase PM energy storage motor drive system is as follows: According to (10) and (12), the predicted values of stator flux and torque at the (k + 1)T s moment can be calculated. Then, the switching signal of the VSI can be obtained by substituting the predicted values and the response values into the cost function (8).…”

“…The structural diagram of the 6*3-phase PM energy storage motor system with PPC strategy is shown in Figure 8. According to Figure 8, the operating principle of the 6*3-phase PM energy storage motor drive system is as follows: According to (10) and 12…”

“…Second, the short-circuit and open circuit faults of the multi-phase PM motor drive system can be collectively referred to as motor phase failure through fault isolation [8,9]. The multi-phase PM motor can run smoothly under the phase failure and has strong fault tolerance and reliability [10]. Therefore, in the field of urban rail transit with higher and stricter reliability requirements, the novel N*3-phase PM energy storage motor with strong fault tolerance and high reliability has more advantages than the conventional three-phase PM motor.…”