Multi-circuit floating voltage suppression method and system

Abstract

The invention relates to a multi-circuit suspension voltage suppression method and system. The multi-circuit suspension voltage suppression method and system are applied to a power supply circuit, wherein in the power supply circuit, a plurality of input branch circuits are mutually independent; and a capacitor is arranged between each phase of each input branch circuit. The multi-circuit suspension voltage suppression method includes the steps: for a suspension branch circuit in the input branch circuits, determining whether a voltage between phases greater than a set first threshold exists; and if so, discharging the capacitor corresponding to the voltage between phases until achieving the preset discharge end condition. The multi-circuit suspension voltage suppression method and system can transfer the suspension energy to positive and negative busbar capacitors while eliminating the residual voltage, can suppress imbalance of neutral point potential, can eliminate imbalance of positive and negative busbar voltages so as to reduce the stress requirement of a switch tube, and can reduce the electric shock risk.

Description

technical field [0001] The invention relates to the technical field of photovoltaic power generation, in particular to a multi-circuit suspension voltage suppression method and system. Background technique [0002] At present, the charging modules widely used in mobile charging vehicles are basically based on the three-phase Vienna structure. Compared with the traditional one-shaped three-level PWM rectifier, the power devices required by the Vienna structure are only half, which reduces the switching loss and Complexity, thus improving reliability, so it has been widely used in high-power PFC circuits. [0003] In some high-power occasions, two Vienna rectifier circuits are often used in parallel. Typical circuits such as figure 1 As shown, its input can be two independent three-phase AC power sources; it can be two diesel engines; or one diesel engine and one power grid. Make sure that when any one input is powered off, the other can also supply power in time. Because o...

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Problems solved by technology

[0007] In order to solve the above-mentioned problems in the prior art, that is, in order to solve the problem of how to transfer the levitation energy to the positive and negative bus capacitors while eliminating the residual voltage, and suppress the imbalance of the midpoint potential, so as to realize the optimization of the two indicators, The present invention provides a multi-circuit suspension voltage suppression method, which is applied to a power supply circuit in which multiple input branches are independent of each other, and capacitors are respectively arranged between phases of each input branch. The method includes:

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