Power Tip Optimize Power Consumption in Satellites

Modern satellites require increasingly powerful power supply systems to support both satellite subsystems and carried payloads. Optimizing size, weight, and power consumption is indispensable for several reasons. How SWaP optimization works.

In satellite technology, the growing demands for data rate, resolution, and sensitivity play a primary role. This is accompanied by the demand for the smallest and lightest possible satellites.

After all, the costs for a satellite launch can range between several thousand and several tens of thousands of US dollars per kilogram, depending on the intended orbit. Additionally, satellites obtain their electrical energy from solar panels, which also cannot be arbitrarily large or heavy. Overall, a so-called SWaP optimization (Size, Weight, and Power) ensures that satellites operate more efficiently in space, improving performance and extending their operational lifespan.

Apart from the demand for maximum efficiency, the power supply system is also required to be suitable for different voltages and currents, as many different topologies are used (Image 1). Image 2 provides an overview of the components and functions of a typical satellite power supply.

In addition to the mentioned solar panels, a battery is present to store electrical energy. It powers the satellite when no sunlight reaches the panels or when not enough electrical energy can be generated from sunlight.

The Power Conditioning Unit (PCU) processes the electricity from the solar panel or battery so that the satellite's systems are supplied with stable and consistent voltage and current.

The Power Distribution Unit (PDU) is responsible for distributing electrical energy from the solar panels and the battery to the various subsystems and payloads. The auxiliary power supply comes into play in the event of a main power supply failure and maintains essential functions until the main power supply is restored.

Develop power supply for satellites with GaN FETs

For the development of satellite power supplies, radiation-hardened GaN FET gate drivers such as the types TPS7H6003-SP (200 V), TPS7H6013-SP (60 V), TPS7H6023-SP (22 V) (each 100 krad TID, SEL-immune up to 75 MeV⋅cm²/mg) and the radiation-tolerant components TPS7H6005-SEP (200 V), TPS7H6015-SEP (60 V), TPS7H6025-SEP (22 V) (each 50 krad TID, SEL-immune up to 43 MeV⋅cm²/mg) are suitable. Additionally, there are PWM controllers like the radiation-hardened TPS7H5001-SP and the radiation-tolerant TPS7H5005-SEP.

As an aid in designing with these components, Texas Instruments offers various reference designs. A non-isolated synchronous buck converter implemented with the aforementioned components, featuring a power output of 300 W, an input voltage range of 50 to 150 V, and an output voltage of 28 V, is optimized for the highly fluctuating output voltage of 100-V solar panels.

An isolated full-bridge converter with a power output of 100 W, an input voltage range of 22 to 36 V, and an output voltage of 5 V features a power stage equipped with GaN FETs. This architecture enables numerous implementations with various output voltages.

Another reference design is available for a non-isolated multiphase buck converter for high currents, equipped with a PWM controller and gate drivers. Input voltages between 11 and 14 V are converted into an output voltage of 0.8 V. Here too, GaN FETs are used in the power stage.

The two-phase implementation delivers currents of up to 80 A, but the design can be expanded with additional phases if necessary to provide higher output currents of 100 A and more, and to generate low output voltages below 0.8 V for modern FPGAs, ASICs, and multicore processors. (kr)

According to documents from Texas Instruments.