No-signal interconnection online type UPS parallel control method

Abstract

The invention discloses a no-signal interconnection online type UPS parallel control method comprising active power and reactive power calculation, phase lock adjustment, self-adaptive virtual resistor adjustment and output voltage control. In the adaptive virtual resistor adjustment, output impedance of a UPS inverter is adjusted to be resistivity. Benchmark amplitude is adjusted by using active power, benchmark angular frequency is adjusted by using reactive power and a benchmark phase is adjusted by using phase lock so that benchmark voltage is co-determined. An absolute value of the reactive power modulates a virtual resistance value so that a self-adaptive characteristic is realized. UPS output current or filtering induction current is multiplied by the virtual resistance value and then negatively fed back to the benchmark voltage so that reference voltage is obtained and the reference voltage is tracked. Closed loop feedback output quantity is modulated via pulse width so that the UPS inverter is controlled. Influence of frequency disturbance on power equalization caused by the phase lock can be effectively reduced so that accurate phase lock of UPS output voltage and commercial power voltage, UPS parallel operation high current sharing and great dynamic characteristic can be realized.

Description

technical field [0001] The invention belongs to the technical field of power supply equipment control, in particular to an on-line UPS parallel control method without signal interconnection. Background technique [0002] With the development of society and the progress of science and technology, UPS (uninterruptible power supply) has been more and more widely used as the power supply of key equipment in important occasions. With the continuous improvement of users' requirements for the reliability and power level of UPS power supply systems, a single UPS has gradually shown its limitations. Modular N+X parallel redundancy technology can greatly improve the reliability, flexibility and capacity of UPS power supply systems , can also effectively reduce the system cost. [0003] The control methods for inverter parallel connection can be divided into wired parallel connection and wireless parallel connection according to whether there are internal signal interconnection lines ...

AI Technical Summary

Problems solved by technology

Both power sharing and phase-locking adjustments need to adjust the output frequency. However, due to different adjustment goals, conflicts are likely to occur, and as a result, the parallel system cannot work stably, and even the parallel connection fails.

Therefore, the wireless parallel technology of the inverter based on PQ droop control cannot be directly applied to the online UPS parallel system.

[0005] The Chinese patent with the publication number CN1581628 discloses a wireless parallel control method and system, which is based on the inductive UPS output impedance and uses the simulated P-ω and Q-V slope droop curves to realize the wireless parallel connection and automatic phase-locking of the inverter and current sharing, but this technology does not take control measures for the adverse effects of the inverter output voltage and the mains phase-locking link on parallel current sharing, and it is difficult to achieve effective phase locking and stable current sharing at the same time

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