Three-phase active harmonic rectifier (AHR) to improve utility input current THD in telecommunication power distribution system

Abstract

Abstract-Modern telecommunication power supply systems have several parallel-connected switch-mode rectifiers to provide 48 Vdc. A typical switch-mode rectifier configuration includes a three-phase diode rectifier followed by a dc-dc converter. Such a system draws significant harmonic currents for the utility, resulting in poor input power factor and high total harmonic distortion. In this paper, a three-phase active harmonic rectifier (AHR) scheme is proposed. In the AHR scheme, a diode rectifier module is replaced by a six-insulated-gate-bipolar-transistor pulsewidth-modulation rectifier to supply load harmonics as well as its own active power. Each dc-dc converter module is connected to a shared 48-V dc link. The AHR module together with parallel-connected switch-mode rectifiers is controlled to achieve clean input power characteristics. The VA ratings of the AHR scheme is compared with an active power filter approach. The control design is based on the synchronous reference frame approach. Analysis, simulation, and experimental results show that the AHR offers several advantages such as lower VA rating, better current control response, efficient use of the AHR dc link, small size, and stable dc-link voltage control.Index Terms-Active harmonic rectifier (AHR), active power filter (APF), telecom rectifier, total harmonic distortion (THD).

A soft‐switching post‐regulator for multi‐outputs dual forward DC/DC converter with tight output voltage regulation

“…Furthermore, various requirements are imposed on power supplies for industry applications including multi‐outputs, tight voltage regulation, fast dynamic responses, high efficiency etc. [2, 3].…”

Reduced Switching-Frequency Active Harmonic Elimination for Multilevel Converters

“…This results in low switching losses, and because of several dc sources, the switches experience a lower dV /dt. As a result, the multilevel-converter technology is a promising technology for high-power electronic devices for utility applications [4], [5] such as flexible ac transmission devices. For these applications, the output voltage of the converters must meet maximum voltage and current total-harmonic-distortion (THD) limitations such as those specified in IEEE 519 [6].…”

“…Generally, different pulsewidth-modulation (PWM) methods such as sinusoidal-triangle PWM and space-vector PWM combined with different control technologies such as feedforward control are widely used [5]- [17]. But, they do not completely eliminate any number of high-order harmonics of the output voltage [18]- [23], and selective-harmonic-elimination method cannot guarantee THD required by applications [24]- [32].…”