Comparative Analysis of 18-Pulse Autotransformer Rectifier Unit Topologies with Intrinsic Harmonic Current Cancellation

Abstract

With the evolution of the More Electric Aircraft (MEA) concept, high pulse converters have gained the attention of researchers due to their higher power quality. Among the high pulse converters, 18-pulse autotransformer rectifier unit (ATRU) offers better power quality level with small size, weight and medium complexity. The conventional topologies of autotransformers that require the use of extra elements such as Inter Phase Transformers (IPT) or Zero Sequence Blocking Transformers (ZSBT), adding to the complexity, weight and size of the overall system, are not considered in the analysis. For 18-pulse rectification, only those topologies of autotransformers which have the intrinsic current harmonic cancellation capabilities are presented here for comparison. These topologies offer current harmonic levels within limits specified by IEEE 519 with reduced weight and size as compared to the conventional multi-pulse converters. A comparison of different differential delta/fork configured 18-pulse autotransformer rectifier units is presented so as to come up with the best among available topologies with respect to weight, size and power quality. Experimental prototypes of each topology were designed and their results are displayed along with the simulation results for comparison.

Wide Bandwidth Control for Multi-Parallel Grid-Connected Inverters with Harmonic Compensation

“…In this paper, the expected improved bandwidth frequency f B is 1250 Hz (25th order harmonic) which is the highest harmonic current frequency of a single HCGI system. According to references [10][11][12][13][14][15][16], if K O_d is greater than 0.5 at high frequency section, the performance of harmonic compensation is acceptable. Besides, according to references [17][18][19][20][21], if the system gain K O_d smaller than 0.2, the resonant peak can be effectively suppressed.…”

“…Over the past decades, with the rapid development of renewable energy generation technology, inverters have been widely used as grid-connected interfaces in renewable energy or energy storage systems [1][2][3][4][5][6][7][8][9]. Recently, the widespread applications of power electronic elements and non-linear loads make voltage and current distortion in distributed generation systems ever more serious [10,11]. Different from the traditional grid, which is equipped with active power filters to compensate the harmonic current, harmonic-compensation grid-connected inverters (HCGIs) having the function of harmonic-compensation while ensuring the power output are employed in distributed generation systems.…”

Design and Comparison of the Performance of 12-Pulse Rectifiers for Aerospace Applications

“…Compliance with existing international standards guarantees the adoption of power converters with acceptable values of total harmonic distortion (THD), power factor (PF), and DC output ripple, leading to increasingly reliable systems. High-harmonic components in currents and voltages and a high ripple rate in DC output voltages may result in resonances overvoltages and other problems of electromagnetic compatibility inside the onboard electrical systems [1].…”

“…Moreover, these components may suffer from detuning [3][4][5][6][7][8][9]. To improve the quality standards and reduce the overall size, AC-DC converters having a higher pulse number have been proposed [1][2][3]. Recently, several authors have investigated solutions based on the use of autotransformers, indicating their possible advantages and suggesting these solutions as alternatives to the use of CTUs [10][11][12][13][14].…”

A 36-Pulse Diode Rectifier with an Unconventional Interphase Reactor

“…Presently, the use of 6-pulse/12-pulse MPR-based phase-shift transformers in industrial applications exhibits high THD. Several MPRs with phase-shift transformers are proposed through various phase-shift transformer connections to increase the output number of the phase-shift transformer [6][7][8][9]. These MPR-based phase-shift transformers are of either isolated or non-isolated type with symmetric configurations.…”