Optimum Design of 48-Pulse Rectifier Using Unconventional Interphase Reactor

Abstract

In order to simultaneously reduce the harmonics of input line current and ripple of load voltage in multipulse rectifier, this paper proposes a 48-pulse rectifier using the unconventional interphase reactor (IPR) with an auxiliary single-phase diode-bridge rectifier at the dc link. The primary winding of the unconventional IPR is triple-tapped, and the secondary winding is connected with a single-phase diodebridge rectifier. The operation mode of the unconventional IPR is analyzed, and the optimal tap ratio and turn ratio are designed. With the optimal parameters of the IPR and the optimal conduction time sequence of power devices, the proposed rectifier extends the conventional 36-pulse rectifier operation to a 48-pulse operation and draws near sinusoidal input line currents, the total harmonic distortion (THD) of which is about 3.81%. The proposed 48-pulse rectifier is easy and simple to implement, and it is more suitable for high-voltage and large-current application. Some simulation and experiments are provided to validate the theoretical analysis. INDEX TERMS Multipulse rectifier (MPR), interphase reactor (IPR), single-phase diode-bridge rectifier, harmonic reduction. II. PROPOSED RECTIFIER WITH UNCONVENTIONAL IPR AND ITS OPERATION MODE A. CIRCUIT CONFIGURATION

Comparative analysis of two different interphase reactors applied in 36‐pulse diode rectifier

“…Substituting (18) into (17), the expression of input line current i a is calculated as (19) shows. Because the input line current is symmetrical, the time interval of (19) is selected to be [0, π/2].…”

“…The output current i d2as of the REC II lags behind i d1as , and the lagged phase angle is π/6. Furthermore, from (17), the input line current i aas can be calculated as follows: By substituting the optimal parameters into (47) and (48), we can obtain the waveform of currents i m , i n , i p , i q i d1as , i d2as and i aas , as shown in Fig. 15.…”

“…Essentially, the passive auxiliary circuit can superimpose a voltage on the output voltage and generate circulating current to reduce the harmonics [15]. Using a passive auxiliary circuit can reduce design complexity and kVA rating of phase-shift transformer, and increase the pulse number of output voltage and step number of input current to improve harmonic reduction ability in an economical way [17].…”