Design and Development of Electronic Power Conditioner for Rubidium Atomic Frequency Standard

This paper describes the design and development of a 70W Electronics Power Conditioner (EPC) using novel antiphase master-slave dual DC-DC converter technique. The outputs are selected as per the power requirements of rubidium atomic frequency standard (RAFS) for navigation payloads of Indian Space Research organization (ISRO). The master converter with four outputs, is designed with forward topology using resonant reset technique. Direct feedback with voltage mode control and type-3 compensator has been adopted for regulation purpose. Slave converter with 43W pulsating load (1.37KHz) is designed around forward topology and cascaded output filters. It is operated in anti-phase with master converter with the help of auxiliary gate drive. Independent multi-stage input filters are designed and implemented on both converters to meet MIL-STD-461E EMI standard. Low dropout regulators are used on all five output lines for post regulation and better dynamic response. Short circuit protection is provided through primary current sensing of both the converters. The EPC is designed to meet very stringent specifications for regulation & Periodic and Random Deviations (PARD), for space environment; as defined by radiation, thermal and EMI limits.