A twelve-pulse voltage-type reversible rectifier and its control method

Abstract

The invention discloses a twelve-pulse voltage type reversible rectification device and a control method thereof. The reversible rectification device includes a main circuit unit and a control unit, and the main circuit unit includes a Y-△ phase-shifting transformer with two secondary windings and a rectification inverter bridge. I and the rectification inverter bridge II, the output terminals of the two windings on the secondary side of the two-winding Y-△ phase-shifting transformer are respectively connected with the rectification inverter bridge I and the rectification inverter bridge II, and the rectification inverter bridge I and the rectification inverter bridge II are two Arranged in series; the control method includes the working mode of constant voltage and current limitation, internal data unitization, PLL phase calculation, DC filtering, setting and feedback difference dead zone limit, working condition judgment, digital discrete PI processing and superposition, The output amplitude is limited and the pulse generates the thyristor control pulse signal of the rectification inverter bridge I and the rectification inverter bridge II. The thyristor of the invention can withstand high voltage levels, can effectively reduce system ripple and total harmonic distortion, and has the advantages of wide application range, low cost and simplified modules.

Description

Technical field [0001] The invention relates to a reversible rectification technology, in particular to a twelve-pulse voltage type reversible rectification device and a control method thereof. Background technique [0002] The industrial high-power rectifier adopts the circuit form of uncontrollable diode and phase-controlled thyristor rectification. The diode rectification has the defects of non-adjustable and irreversible DC voltage. Phase-controlled rectifiers are susceptible to voltage distortion caused by thyristor triggering and turn-on. Phase detection fluctuations and oscillations, low system dynamic performance, and difficult to achieve reversible rectification control; six-pulse full-controlled bridges or half-controlled bridges have low power factors and harmonics The distortion is large; it is easy to lose control during inverter, and it is not suitable for high-power applications. Conventional high-power rectifiers in the form of diode and thyristor rectification, ...

AI Technical Summary

Problems solved by technology

Phase-controlled rectifiers are susceptible to voltage distortion caused by thyristor triggering and conducting phase detection fluctuations and oscillations, low dynamic performance of the system, and difficult to achieve reversible rectification control; six-pulse full-controlled bridge or half-controlled bridge has low power factor and harmonics Large distortion; it is very easy to get out of control when inverting, so it is not suitable for high-power applications

Conventionally, the form of high-power rectifier with diode and thyristor rectification is limited by the reasons and structure of the device itself, such as uncontrollable diode rectification and soft load characteristics; although the rectification form of phase-controlled thyristor is controllable, the six-pulse wave and The following pulse rectification methods will lead to low system power factor (PF), high harmonic content (THD), large voltage fluctuations and low power utilization; twelve-pulse thyristor rectifiers are susceptible to grid distortion during the commutation process of the main circuit In many cases, it will cause phase mismeasurement and oscillation, which will eventually lead to false triggering of thyristors, and the system's anti-interference ability is low

In addition, the thyristor rectification scheme needs to simultaneously collect three-phase AC voltage and current signals, and DC voltage (and current) signals to form a closed control loop. The use of Hall devices on the AC side also requires additional power supply, resulting in more system components, increased costs, and reduced reliability.

For a thyristor rectifier system without inverter function, if the system is operated with an inverter under certain circumstances, the system cannot operate normally when the energy is fed back to the DC bus, causing the DC voltage to rise and cannot be fed back to the grid.

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