The invention provides a multi-port back-to-back suture-ring-free power conversion device and method, and belongs to the field of low-
voltage power distribution network closed-loop power conversion, and the device is specifically characterized in that a series
voltage compensator is connected with a parallel converter through a DC
coupling capacitor; the two ends of the compensation side of the series
voltage compensator are connected with a
loop closing switch and a multi-port
circuit breaker respectively; the other side of the
loop closing switch is connected with the other multi-port
circuit breaker; the number of ports of the multi-port
circuit breaker is equal to that of the power supplies; the parallel
voltage converter is used for maintaining the voltage of the common direct-current
bus to be constant and performing
harmonic compensation on load current; the
alternating current side is connected to a load through an
electricity-taking circuit breaker to take
electricity; the series voltage compensator is used for providing compensation voltage and adjusting the amplitude and phase of the voltage at the output end of the
loop closing switch; and the multi-port circuit breaker provides a plurality of transfer power supply lines for each power supply area. According to the invention, the cost is greatly reduced, the closed-loop power conversion device is simplified, the closed-loop
impact current can be eliminated, and the power supply reliability is improved.