High-voltage inverter sharing direct current (DC) bus

Abstract

The invention relates to a high-voltage inverter sharing a direct current (DC) bus. The high-voltage inverter sharing the DC bus comprises a charging circuit, a phase-shifting transformer, three-phase diode rectifier bridges, a high voltage DC bus and an inverter based on multi-media card (MMC) topology. The primary side of the phase-shifting transformer is connected with a power grid through the charging circuit, each subsidiary side output winding of the phase-shifting transformer is connected with the three-phase diode rectifier bridge, the output capacitors of each diode rectifier are connected in series to form the high voltage DC bus, the high voltage DC bus is connected with the public DC end of one inverter or multiple inverters based on MMC topology, and the output ends of the inverters are connected the electric motor to be detected, and the mixed frequency test and the frequency control function of the electric motor is achieved. The topologic scheme of the high-voltage inverter sharing the DC bus meets the requirements of the electric motor test station of a weak grid end, multiple-unit output of the phase-shifting transformer with multiple windings is used, the DC bus formed by the series connection of the diode rectifying capacitors is used to store the energy extracted and fed back when the electric motor mixed frequency test is carried out, the energy is no longer loaded by the power grid, and therefore the pollution to the power grid caused by the electric motor test is eliminated.

Description

technical field [0001] The invention relates to a common DC bus high-voltage frequency converter, in particular to a high-voltage frequency converter used for motor temperature rise experiment and motor speed regulation. Background technique [0002] Nowadays, more and more high-voltage frequency converters are used in the temperature rise experiments of asynchronous motors for overlapping experiments. It can be seen from the principle of the motor that during the frequency superposition experiment, the frequency converter simultaneously sends out the voltage U1 of the main frequency F1 and the voltage U2 of the sub-frequency F2. At this time, the tested motor periodically works in the motoring and generating states. When a conventional four-quadrant high-voltage inverter is used for frequency superposition experiments, a fully-controlled rectifier bridge is used to balance the DC voltage of each unit. When the motor under test is working in a motor state, the inverter extra...

AI Technical Summary

Problems solved by technology

[0003] When the motor test station at the weak end of the industrial power grid (10kV power grid, 7MW power grid capacity) needs to perform high-power motor superposition experiments, the grid voltage is destroyed due to the excessive energy extracted or fed back by the four-quadrant high-voltage inverter to the grid side Stable, causing other electrical equipment to fail to work

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