Research On Distributed PMG Stabilized Power Supply Based On Speed-regulating Of Prime Mover

Compared with traditional mechanical drive,electric drive has been widely used because of its advantages of convenient control and fast response,as the main power or standby power supply,distributed power supply has been widely used in many fields,such as electric driven ship,aerospace,emergency rescue,field work and so on.The traditional distributed power supply mostly adopts the mode of diesel engine driving electric excitation synchronous generator,and directly outputs the power frequency alternating current to meet the load demand through the double closed-loop control of output voltage and prime mover speed.With the increasing load of frequency converter,the generator set is required to be able to output DC to meet the inverter or DC load demand,which is no longer limited to power frequency AC.In order to overcome the shortcomings of traditional distributed generation,such as low efficiency,complex structure and low power density,stabilized power supply based on speed-regulating of prime mover is proposed.The structure and control principle of the regulated power supply are described,and the influence of uncontrollable rectifier load on the output performance of permanent magnet generator is studied.The power balanced control strategy based on slave speed-regulating is proposed,which can realize the control purpose of output power distribution according to the capacity of each generator set,the main research contents are as follows:Firstly,the structure and operation principle of the distributed permanent magnet generator stabilized power supply based on speed-regulating of prime mover are studied.The stabilized power supply uses the prime mover to drive the permanent magnet generator,and its output three-phase alternating current is converted into direct current through uncontrolled rectification.When the load changes,the DC output voltage is kept constant at a given value by adjusting the speed of the prime mover.Due to the existence of rectifier,the limitation of power supply on frequency is eliminated,and prime mover and generator with higher speed can be used to improve the power density of generator set to meet the requirements of high efficiency,small volume and light weight.Secondly,the influence of pole pairs on the volume,cost and performance of the generator is studied,the influence of permanent magnet generator parameters on the q-axis inductance,d-axis inductance and salient pole ratio is analyzed.The influence of pole arc coefficient,eccentricity and slot size on the permanent magnet generator back EMF waveform distortion rate is studied.The influence of the magnetic separation bridge size,the permanent magnet slot chamfering and the permanent magnet segmentation on the stress of the rotor lamination of the permanent magnet generator are studied.Reasonable design can reduce the flux leakage coefficient of permanent magnet motor and improve the material utilization rate.Thirdly,the influence factors of voltage regulation rate of permanent magnet generator are studied,and the influence of load variation,salient pole ratio and speed variation on generator output voltage is analyzed,which provides theoretical basis for seeking a method to maintain generator output voltage constant.By using analytical method and field circuit coupling simulation method,the change law of output voltage of permanent magnet generator with load rate is studied,and the change law of generator speed with load rate when the output voltage of generator is kept constant is studied.The accuracy of the research content is verified by experiments.Fourthly,the influence mechanism of uncontrollable rectifier on the output voltage and current waveform of permanent magnet generator is studied.The influence of commutation overlap angle on output voltage and current waveform of permanent magnet generator is analyzed,and the effect of inductor and LC passive filter circuit on the output voltage and current waveform of generator is studied.The influence of uncontrolled rectifier load on waveform quality,voltage regulation rate,load capacity,torque ripple and loss of permanent magnet generator is studied,which has a guiding role for the reasonable selection and optimal design of the rated parameters of permanent magnet generator with uncontrolled rectifier load.Fifthly,the influence of synchronous inductance,RMS value of output voltage and phase difference of output voltage on load balance of DC stabilized power supply is analyzed.A power balanced control strategy based on slave speed-regulating is proposed.The generator set that starts first is used as the master to stabilize the voltage,By adjusting the speed of the slave,the effective value of the output voltage of the slave is changed,and then the ratio of the output power of the slave and the master is adjusted to realize the control purpose of the output power of each generating set according to the capacity.Finally,the accuracy of the control strategy is verified by the experiment of two generator sets operating in parallel.The distributed permanent magnet generator stabilized power supply based on speed-regulating of prime mover is proposed,and its control structure and operation principle are analyzed,and the new problems brought by the new stabilized power supply are studied,the effectiveness of the research method and content of the new stabilized power supply is verified by experiments.The new stabilized power supply can meet the needs of large capacity,high power density,high efficiency,small volume,light weight,and so on.The research in this paper can promote its further application and promotion,and provide a theoretical basis.