12-pulse Rectifier System Research Articles

Simulation Analysis of Overvoltage of Single Phase Grounding Fault in Paralleled 12-Pulse Rectifier System

In order to solve the problem of overvoltage of single phase grounding fault of paralleled 12-pulse rectifier system, firstly the common mode wave problem of monopole in DC side at fault is analyzed. Secondly, the transient overvoltage of the system at the AC side single phase fault is analyzed by simplifying the charging and discharging circuit of capacitances on DC side. Finally, the theory of frequency extinguishing arc is used to simulate the intermittent arc grounding overvoltage. It is proved that the capacitance on DC side also affects the AC overvoltage in the system that provides a basis for the better suppression of overvoltage in the project. The correctness of the conclusion is verified by PSCAD/EMTDC simulation software in the analysis process.

Influence of DC Grounding Mode on DC Fault Characteristics in Ship Medium Voltage Power System

At present, in the background of the multiphase rectifier system is widely used in medium voltage ship power system, the influence of DC grounding mode on the characteristics of DC monopole fault is analyzed for series 12-pulse uncontrolled rectifier system and paralleled 12-pulse uncontrolled rectifier system respectively. By establishing the electromagnetic transient model of the medium voltage power system under different topologies, fault voltage, recovery speed and fault current under different grounding modes are simulated and studied, and the fault mechanism is deeply analyzed, and the advantages and disadvantages of different grounding modes are compared. As a conclusion, for series 12-pulse rectifier system, the way of high impedance grounding through the middle point of the two series rectifier bridges is proposed. For paralleled 12-pulse rectifier system, high resistance grounding mode through the middle point of split capacitances on dc side is proposed, they are beneficial to improve the stability and transient performance of the system. That it is beneficial to improve the stability and transient performance of the system.

Effect of Voltage Transformation Ratio on the Kilovoltampere Rating of Delta-Connected Autotransformer for 12-Pulse Rectifier System

This paper presents the effect of voltage transformation ratio on the kilovoltampere rating of delta-connected autotransformer for 12-pulse rectifier system and gives an optimal configuration of the autotransformer with minimal kilovoltampere rating and the least windings. According to the phasor diagrams and the relation between the output voltage and input voltage of the autotransformer under different connection ways, the effect of voltage transformation ratio on current through windings is analyzed, and corresponding expressions and waveforms of the currents are also obtained. Consequently, a relation between the position parameter and output power is established, and based on the relation, the effect of winding configuration on the kilovoltampere rating of the autotransformer is analyzed, which can be used to obtain the optimal configuration. From the theoretical analysis, an autotransformer with optimal configuration and minimal equivalent kilovoltampere rating is designed. Some simulated and experimental results show the correctness of the theoretical analysis.

Interactions within heterogeneous systems of uncontrolled rectifiers for aircraft electrical power systems

There is an increase in the use of multi-pulse, rectifier-fed motor-drive equipment on board more-electric aircraft. Motor drives with feedback control appear as constant power loads to the rectifiers, which can cause instability of the DC filter capacitor voltage at the output of the rectifier. This problem can be exacerbated by interactions between rectifiers that share a common source impedance. In order that such a system can be analysed, there is a need for average, dynamic models of systems of rectifiers. In this study, an efficient, compact method for deriving the approximate, linear, large-signal, average models of two heterogeneous systems of rectifiers, which are fed from a common source impedance, is presented. The models give insight into significant interaction effects that occur between the converters, and that arise through the shared source impedance. First, a 6-pulse and doubly wound, transformer-fed, 12-pulse rectifier system is considered, followed by a 6-pulse and autotransformer-fed, 12-pulse rectifier system. The system models are validated against detailed simulations and laboratory prototypes, and key characteristics of the two system types are compared.

Comparative Evaluation of Three-Phase High-Power-Factor AC–DC Converter Concepts for Application in Future More Electric Aircraft

A passive 12-pulse rectifier system, a two-level, and a three-level active three-phase pulsewidth-modulation (PWM) rectifier system are analyzed for supplying the dc-voltage link of a 5-kW variable-speed hydraulic pump drive of an electro-hydrostatic actuator to be employed in future More Electric Aircraft. Weight, volume, and efficiency of the concepts are compared for an input phase voltage range of 98-132 V and an input frequency range of 400-800 Hz. The 12-pulse system shows advantages concerning volume, efficiency, and complexity but is characterized by a high system weight. Accordingly, the three-level PWM rectifier is identified as the most advantageous solution. Finally, a novel extension of the 12-pulse rectifier system by turn-off power semiconductors is proposed which allows a control of the output voltage and, therefore, eliminates the dependency on the mains and load condition which constitutes a main drawback of the passive concept.

A robust three-phase active power-factor-correction and harmonic reduction scheme for high power

This paper proposes a robust three-phase active power-factor-correction (PFC) and harmonic reduction scheme suitable for higher power applications. The proposed system is a unique combination of a low-kilovoltampere 12-pulse rectifier system with a single-phase boost PFC scheme to shape the input current to near sinusoidal waveshape. The voltampere rating of the active PFC converter is 0.05 pu and is not exposed to line transients under varying load conditions. The proposed system is suitable for utility interface of higher power rectifiers employed in power supplies and adjustable-speed drive systems which demand clean input power characteristics in the range of 1-500 kW. The proposed system is rugged and, in the event the active control were to fail, the system reverts to 12-pulse operation with fifth and seventh harmonic cancellation. Analysis and design of the system is examined in detail, and simulation and experimental results on a 10 kVA prototype are shown.