Novel isolated multi-pulse rectifiers with low current distortion using three-phase half-controlled boost converters

Abstract

Since the AC-DC conversion is widely spread in power sources, this work proposes a novel strategy of multi-pu[se topologies, associated to the ha[f-controlled boost-based rectifier, which has the follows main advantages: [ow Total Harmonic Distortion of the line current (THDi), below 2%; Power Factor (PF) close to unit; simple gate drive circuit, since all active switches are connected to the same reference; robustness given that the DCM operation results the peaks of the current naturally follow the voltage waveform. The control circuit becomes very simplified because all the switches are synchronized and only one basic voltage loop should be used to regulate the DC output, without current sensors. In addition, the commutation process occurs after the current in the diode becomes zero (DCM), without losses and current stresses due to the diode reverse recovery. The simulation analysis shows a significant improvement of PF once the THDi is lower than 2% while the conventional 12-pu[se topologies have about 14%. Each conventional three-phase bridge rectifier is replaced by a three-phase ha[f-controlled boost based topology, also called of bridge[ess rectifiers. A 2.5 kW prototype is being built and its feature is a strong candidate for More Electric Aircraft (MEA) and Adjustab[e Speed Drive (ASD) applications.

12-Pulse Rectifier with Two DCM Boost-Type Half-Controlled Bridges for Variable- Input-Frequency Applications

“…10 along with the grid line voltage v ST . It is important to note that although the phase supply voltage (V i ) is equal to 84V, because the configuration employed (Wye step-down), the rms value of the line voltage (V L ) in the secondary will respect (11).…”

“…The 12-pulse converter with two embedded HCC, shown in Fig. 1, presented in computational analysis a THD i of 1.73%, significantly below the 14% reported by the one without the active switches, which allows concluding that the incorporation of HCC can be an alternative to increase the order of pulses, resulting in harmonic content reduction, without incurring a significant increase in the weight, volume and complexity of the final structure [11]. In general, the operation in DCM has the dealing with higher values of peak current in the switches as a downside [12], [13].…”

“…This paper aims to continue the research proposed by [11], by implementing a small-scale prototype and pushing the state of art further, adding the analysis of the impact of power supply frequency variations (30Hz -120Hz) in the input current waveform. The possibility of working in a wider range of power supply frequencies combined with its structural advantages make the 12-pulse HCC-embedded converter more attractive for applications with higher requirements for input current harmonic content, meeting, for example, the THD i criteria established in MIL-STD-704F (for aircraft) [14], [18].…”

“…The incorporation of the HCC operating in the DCM to the traditional 12-pulse rectifier allows taking advantage of the angular displacement, canceling the most significant harmonic components presented by the structure (5 th and 7 th ) in this mode of conduction [9], as well as to reduce the complexity of the control circuit, making possible the operation even in an open-loop, commanding all active switches by the same control signal [11].…”

Verification of Lossless ZVS Condition for Three-Phase AC-DC CIHRC

“…Thus, in order to avoid the harmonic pollution of the utility system, several standards such as the IEEE Std. 519 have been developed and were being enforced on the harmonic content of the current and voltage drawn by power electronic converters [1], [15], [17]. To solve this problem, other options such as power factor correction (PFC) converters and active power filter technique to compensate for the harmonic current generated by the diode rectifiers have been developed extensively [14].…”