High power shunt regulation of spacecraft solar arrays

The operation of the basic shunt system for solar arrays is considered. The system is analyzed for stability with a constant power load. The implications of using switching type shunt elements for high power outputs are investigated.

The input filter is shown to affect the closed loop design of the system, as well as its weight. Analysis and modeling techniques are developed for a sequential shunt unit. The analysis of bus impedance and loop gain is verified against measurements on hardware. The factors that affect the design are described. The effect of non-linearities in the system is shown to cause limit cycle operation.

For more effective use of the input filters, alternatives to the existing scheme are considered, where the on-off and fine control sections are kept distinct. The basic requirements of the scheme are shown to be the suppression of on-off section current, and the inclusion of hystcresis in the control loop.