Design Of Stabilized-voltage Stabilized-frequency System For Fishing Boat Shaft Generator Power Grid

The fishing boat shaft generator is used as the fishing boat power supply device driven by main diesel engine,which has the advantage of saving energy and does not need to be equipped with additional diesel engine compared with the diesel generator,and it has been widely used in the use of fishing boat power supply equipment.However,due to the complexity of the stabilized-voltage stabilized-frequency system of the conventional shaft generator,the large running loss,the difficulty of maintenance,and the difficulty of longterm grid-connected operation with the fishing boat power grid have become obstacles to the promotion of the shaft generator system.Aiming at the redundancy of the stabilized-voltage stabilized-frequency system equipped with the traditional shaft generator,this paper proposes a light stabilized-voltage stabilized-frequency system for the fishing boat shaft generator based on BOOST module,which includes uncontrolled rectifier-BOOST-inverter.Firstly,the uncontrolled rectifier circuit is controlled for the rectification link,which improves the power factor of the rectification link.Then for the boosting link,the system makes full use of the BOOST circuit boosting characteristics,and introduces the closed-loop PID control system to optimize the BOOST circuit function,so that the BOOST circuit has a boost function and a voltage stabilization function.In addition,the article compares the SVPWM control technology,SPWM modulation technology and SHEPWM control technology in the inverter link of the stabilized-voltage stabilized-frequency system,and concludes that the SHEPWM control technology has good harmonic suppression on the voltage output waveform.For the nonlinear transcendental equations of the fundamental amplitude and the amplitude of the harmonics to be eliminated,the 1/4 cycle symmetry is limited in the output waveform modeling process,so that some harmonic components can cancel each other,and finally Newton iteration The method linearizes the switching angle sequence of the SHEPWM waveform and outputs the voltage of the corresponding amplitude and frequency.Because the Newton iteration method is more strict on the initial value requirements,this paper also analyzes the advantages and disadvantages of the empirical formula method to solve the initial value and the SPWM method to solve the initial value.It is concluded that the initial value solved by the SPWM method is more likely to converge to the SHEPWM control switch angle optimal solution.