The invention discloses a 
current source type PWM (Pulse-Width Modulation) 
rectifier and a grid-connected control method based on a virtual 
resistor. A grid-connected 
rectifier consists of commercial power, an alternating-current filtering 
inductor, an alternating-current filtering 
capacitor, a three-phase 
current source type 
rectifier, a direct-current 
inductor, a direct-current 
capacitor and a digital controller. Sampled alternating-current filtering 
capacitance voltage is transmitted to a 
microprocessor to perform digital 
phase locking, and after 
phase locking is finished, the alternating-current filtering 
capacitance voltage and phase are transmitted to an alternating-current controller. The alternating-current controller consists of a coordinate converter, a 
virtual impedance regulator and a divider. The coordinate converter converts the three-phase alternating-current filtering 
capacitance voltage into the voltage under a two-phase static coordinate 
system, after the voltage is regulated by the virtual resistance 
regulator, current passing through a virtual 
resistor is obtained, control amount of the alternating-current side is obtained through the divider, the control amount is superposed on the control amount on the direct-current side, a driving 
signal obtained through a PWM generator is transmitted to a driving plate, and after the 
signal is amplified by the driving plate, the connection and disconnection of a three-phase 
current source type rectifying bridge switch are controlled. The 
control effect of the virtual resistance 
regulator in the alternating-current controller is equivalent to the 
control effect that a 
resistor is directly connected in parallel on an alternating-current 
capacitor, so that oscillation can be effectively damped, loss is not caused, and ultraharmonics in grid-connected current can be effectively inhibited. The rectifier is high in dynamic response speed, stable in dynamic response and high in 
power factor, the 
total harmonic distortion rate of the grid-connected current is low, and the method can be applied to an 
uninterruptible power supply.