Three-level power electronic traction transformer of non-power frequency transformer

Abstract

The invention discloses a three-level power electronic traction transformer of a non-power frequency transformer. An input reactor L is connected with a traction network (V) to realize the vehicle-mounted power transformation, n identical function modules (M1-Mn) which are connected by input serial connection and output parallel connection are adopted, and each module is a power electronic device of an alternating current-direct current converter with a single-phase structure. The transformer is characterized in that a power electronic device consists of a single-phase diode inserting type three-level rectifying circuit and a half-bridge three-level bidirectional direct current-direct current converter. The transformer has the advantages that the structure is concise, and the requirement of the resonance is not necessary to meet ; the size of the system is greatly reduced, the working efficiency and electric energy quality are improved, the system is controllable, and the easiness in adverse effects, such as resonance, is avoided; the three-level output is realized, the current returning energy in the single switch cycle is reduced, and the energy transmission efficiency is greatly improved.

Description

technical field [0001] The invention relates to a power electronic traction transformer, in particular to a locomotive-mounted power electronic traction transformer without a power frequency transformer in the traction network. Background technique [0002] figure 1 Shown is the circuit structure of the transformer model of the traditional vehicle-mounted converter system. The figure includes AC traction network, three-winding power frequency transformer, single-phase pulse rectifier and traction inverter. The traction network is connected to the beginning of the primary winding of the three-winding power frequency transformer; the two secondary windings are respectively connected to two PWM pulse rectifiers, and the output side of the rectifier is connected in parallel and connected to the traction inverter. The traditional traction transformer traction chain is very heavy, the efficiency is relatively low, the power quality is not high, and additional harmonic compensati...

AI Technical Summary

Problems solved by technology

However, due to the withstand voltage limit of the switch tube IGBT, the voltage level of each module is low when the traction network is in normal operation, resulting in too many cascaded modules and reduced system reliability, which brings difficulties to control and implementation

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