Abstract:The diode threelevel neutralpointclamped (3LNPC) converter with full power is a promising multilevel topology in the application of wind power generation system. In view of the 5MW directdrive wind power generator with permanent magnet

this paper investigated the control system

main loop parameters

stator flux estimation and discontinuous pulsewidth modulation (DPWM) of the fullpower 3LNPC converter. The gridside converter emploied the grid voltage oriented control and space voltage pulse width modulation (SVPWM) strategy

while the rotor field orientated vector control and DPWM strategy were adopted in the rotorside converter. In addition

lowpassfiltercompensationintegrator (LPFCI) based rotor flux position estimation control method is proposed. The result of thermal simulation indicates that when the switching frequency of the gridside converter is 1.55kHz

the junction temperature and temperature rise of IGBT conform with design regulation. Furthermore

the 25kw experimental prototype illustrates that based on the technique and stator flux estimation as mentioned in the paper

the harmonics content is quanlified with international standards，and the system has small rotor position estimation error

excellent steadystate performance and torque dynamic response meeting with systematic control requirements.