It is difficult for the traditional unified power quality controller（UPQC）to effectively solve the deep voltage sag problem and the control is relatively complicated due to existence of coupling between the series and parallel sides. Therefore

a kind of UPQC scheme based on parallel voltage source converter is proposed in this paper

which can overcome the shortcomings of traditional UPQC. The new UPQC topology consists of two independent parallel voltage source converters

which realize active power filter（APF）and dynamic voltage regulator（DVR）functions respectively. The switching strategy of APF unit and DVR unit is proposed. For the control of DVR unit

a segment-type control strategy based on DVR DC side voltage is proposed

and the calculation method of capacitor capacityof DVR DC side is given. A 50 k VA prototype is developed and tested by a third-party professional test institution. Both feasibility and effectiveness of the new UPQC scheme are verified by the test.