Sequential Switching Shunt Regulator Parallel Power Processing Control for High Capacitance Solar Arrays

Abstract

This paper presents a new control strategy for reducing the switching losses produced by the use of high parasitic capacitance solar arrays in the sequential switching shunt regulator. Instead of dividing the solar array into equal sections, the proposed strategy is based on two different sections types, low-capacitance and high-capacitance ones. In order to reduce the switching losses and to maintain the original closed-loop response, a novel parallel power processing control strategy is implemented. With this new technique the low-capacitance sections are the only ones that switch at high frequency to regulate the bus while the high-capacitance sections are only connected or disconnected under high load power changes. In addition, the control closed loop delay associated to the time needed to charge the parasitic capacitance has been modelled and a controller modification is proposed to reduce AC performance degradation.

Predicting Spacecraft Telemetry Data by Using Grey–Markov Model with Sliding Window and Particle Swarm Optimization

“…Te solar array and batteries provide all of the power the spaceship needs. A widely-utilized solar array subsystem is a shunt regulator because of its superior efciency's small mass, simplicity, and high reliability [36]. Te shunt regulator (SR) can be considered as the heart for delivering the spacecraft's power system; it works when sunshine is available to provide the mandatory energy for the bus through solar arrays and shunts unnecessary current produced via solar arrays to ground [37].…”

Power Bus Management Techniques for Space Missions in Low Earth Orbit

“…Each of them is also equipped with a shunt switch that can be tripped on in order to block power transfer to the bus (Figure 1). In order to reach a power balance between solar array generation and load absorption, the active solar array sections are set according to a pre-ordered sequence [4]: when the required solar array generation G SA is smaller than the power supplied by M solar array sections, but larger than the power supplied by M − 1 of them, rough regulation is provided by keeping M − 1 sections permanently enabled and the other N-(M − 1) permanently disabled. Fine regulation is achieved by hysteretic control of the duty cycle on the shunt switch of a single solar array section.…”

“…The trade-off between MPPT and S 3 R has been widely debated in the space power community [4,11], as both provide specific advantages. This led to several proposals to combine the specific advantages of both techniques [23,24], also developing techniques tailored for specific applications [26,27].…”

“…The challenge of merging MPPT functionality into S 3 R systems with no reduction in reliability and a negligible increase in complexity was first faced in [24]. The proposed approach was to enslave the bus voltage in S 3 R to an MPP tracker [4]. This can be done by minimal modifications to the classical S 3 R circuitry and has a main drawback, related to the wide variations of the bus voltage (tens of volts) arising from V MP variations.…”

“…Since the 1970s the most widely used approach for spacecraft power conditioning has been Sequential Switching Shunt Regulation (S 3 R) [2], because of its high power density, modularity, simplicity, and inherently high reliability. Such shunt regulators also provide high power-path efficiency [3,4], as a solar array is split into sections that can be either directly connected-to or disconnected-from the power bus, as happens in the other regulation schemes belonging to the wider family of Direct Energy Transfer (DET) regulators: the Sequential Switching Shunt Series Regulator (S 4 R) [5], the Astrobus™ [6], the shunt module developed for the Galileo Power Conversion and Distribution Unit (PCDU) [7], and the Sequential Switching Shunt Maximum Power Point Regulator (S3MPPR) [8].…”