Energy saving simulation test complex for spacecraft power supplies full-scale electrical tests

The aim of this paper is to describe an energy saving automatized simulation test complex used for spacecraft power supplies full-scale electrical ground-based tests.  The complex allows you to simulate the operation of solar array, lithium-ion-battery and spacecraft payload. The distinctive features of the test complex are a continuous and impulse control methods combination with  an improved dynamic accuracy, and recuperation of consumed energy into its internal DC network for the better energy efficiency. Test complex operational time from uninterruptible power supply accumulator batteries is significantly increased due to the recuperation of excess power into the test complex internal DC network. The results are experimentally proved.

The authors of the paper analyzed dynamic accuracy improvement and energy saving during ground-based spacecraft power system electrical tests. The process of ground-based spacecraft electrical testing includs the following tasks:

• the accurate simulation of static and dynamic characteristics of spacecraft power system energy sources and loads;
• the utilization of energy produced by power system under load and during spacecraft battery charge simulation.

The paper deals with the description of energy saving automatized simulation test complex (ESAST) including complex subsystems structure and experimental study of the test complex characteristics.

Commercially available simulation test complexes usually use continuous or impulse control methods. The continuous control methods decrease energy efficiency, as the most part of energy is dissipated on the regulator, which
requires massive heat sink, increasing weight and size. It makes difficult to produce high-power test complexes. The impulse control methods provide better energy efficiency, but limit dynamics and real devices fast response reproduction accuracy. The paper describes the combination of continuous and impulse control methods with the aim of taking the advantages of both.

The energy consumed by the test complex can be utilized either by the heat dissipation in the environment or by the recuperation into industrial AC grid. The heat dissipation reduces the energy efficiency, increases the testing room temperature (in case of high-power spacecraft power system) and an air conditioning system.  The recuperation into AC grid is free of specified disadvantages, but it requires the recuperated excess energy parameters matching with AC grid requirements through the network of grid-tied inverters, which leads to the increase of weight and size of the test complex. Moreover, the recuperation into AC grid is difficult during grid emergency shutdown, which can result in long test failure. The paper describes the method of excess energy recuperation into the complex internal DC network. The method significantly reduced test complex energy consumption, which in case of powering test complex from uninterruptible power supply (UPS) notably increase operating time from UPS accumulator batteries during AC grid emergency shutdown.

In conclusion the main advantages of ESAST are given:

• more than twice wattage reduction of test complex main power supply;
• the ability to work during AC grid emergency shutdown with increased operating time from UPS;
• the significant reducing of ESAST main parts weight and size.