In this post, we provide an overview of Electrical Power Systems (EPS) and share details of various products on the global market - if you’re familiar with this technology and would like to skip over the introductory material to get straight to the product listings, please click here.
The primary role of the Electrical Power System (EPS) is to supply other systems in the satellite with the necessary electrical power to operate effectively.
The source of the power is the energy collected from the solar panels which are exposed to direct solar radiation or to indirect radiation from albedo.
Batteries are installed alongside the solar panels to store energy which can then be used when the satellite regularly passes through the shadow of the Earth. Batteries can also help to provide sufficient power during periods of peak demand by the payload on-board the satellite.
The collected and stored power must then be distributed to other systems throughout the satellite as needed by the EPS.
The satellite itself may need multiple voltage levels for different sensors and sub-systems. Managing these levels is another function of the system; the EPS houses a power conditioning unit which is able to deliver the required amount of electrical power at several voltages.
It also plays an important role in monitoring spacecraft status.
Assessing satellite status
The health of the satellite needs to be checked regularly to make sure that there are no major problems in any sub-system during its operations in orbit.
Collecting routine information from various sub-systems and sensors is also a core function of the EPS. This involves measuring various important voltages, currents, and temperatures which are called the “Housekeeping Parameters.”
These are communicated back to the ground as a part of the telemetry of the satellite for operators to keep track of the overall health of their system and guard against potential faults or poor performance.
The high levels of radiation in space can cause ”single event latch-up” in the semiconductor devices on the satellite.
This can damage some of the components on the satellite if the power is not turned off quickly enough, so the EPS is also required to protect the satellite and its sub-systems against over-currents.
Electrical CubeSat requirements
There are certain electrical requirements that are recommended for the standard CubeSat form factor which EPSs should adhere to:
- If the satellite features a rechargeable battery it should be fully discharged or deactivated for the launch.
- In order to avoid RF or electrical interference of primary payloads, or the launch vehicle itself, no CubeSat electronics should be active during launch.
- For each CubeSat at least one deployment switch is required, although two are recommended. These should be located at clearly designated points.
- If developers wish to perform testing and battery charging after integration they must provide ground support equipment (GSE) that connects to the CubeSat through designated data ports.
- A remove before flight (RBF) pin is usually required in order to deactivate the CubeSat during integration outside the P-POD or alternative launch separation system. This pin will then be removed once the CubeSats are placed inside the P-POD, and it must fit within the designated data port.
More information on these recommendations can be found in this paper on CubeSat Design Specifications [PDF].
Electrical Power Systems on the global market
In this section, you can explore Electrical Power Systems available on the global market. These listings will be updated when new EPS products are added to the global marketplace for space at satsearch.co - so please check back for more or sign up for our mailing list to get all the updates.
We have also put together an overview of CubeSat solar panels if you need additional power components to complete your satellite and an overview of on-board computers should you require ancillary control systems.
You can click on any of the links or images below to find out more about each of the products. You can also submit a request for information (RFI) on the product pages or send us a general query using our RFI tool to discuss your specific needs, and we will use our global networks of suppliers to find a system to meet your specifications.
Please note that this overview primarily includes integrated EPS products which typically contain the following:
- Solar panels to generate power,
- Power regulation systems for solar generation, such as Maximum Power Point Trackers (MPPTs),
- Batteries to store energy until needed, and
- A Power Control Unit (PCU) to manage energy output from the EPS to the satellite.
We will go into more detail on those components and modules that are commercially available in future overview articles.
The PCDU-P3 and MPPT-P3 Electrical Power Systems by Space Inventor
PCDU-P3 - a 12-channel power unit in a rugged, compact and modular enclosure. The system features 6 independent and customizable step-down converters and a boost converter that can be connected to output channels as required. The PCDU-P3 architecture allows designers to allocate one sub-system per connector, whereby many of the EMI issues experienced on shared power busses are eliminated. This makes the PCDU-P3 very suitable for missions with demanding payloads and sensitive receivers.
MPPT-P3 - a 7-channel maximum power point tracker and battery charger module. Designed for durable, simple and robust satellite integration, it consists of 7 variable frequency DC-DC converters that ensure optimal operating voltage for each solar cell array across all operating radiation levels and temperatures.
Electrical Power Systems by EnduroSat
EnduroSat manufactures a range of EPS products to meet different smallsat requirements. The portfolio consists of:
EPS – Power Module (Incl. Battery Pack) - A versatile EPS that is fully compliant with the CubeSat standard and features a very high efficiency. The module has flight heritage including meeting ISS-level requirements.
EPS – Power Module I PLUS (incl. 2X Battery packs) - featuring very high power efficiency and supporting a wide range of outputs. The system has expanded battery capacity, has flight heritage (including meeting ISS-level requirements) and is fully compliant with the CubeSat standard.
Power Module Type II incl Battery Pack - built to support payloads with high power requirements. It supports multiple outputs, has a high power efficiency and is fully compliant with the CubeSat standard.
This power conditioning and distribution unit is designed to meet a wide variety of customer requirements and features up to 96% MPPT and output converter efficiency. It is compatible with different sized and configuration solar panels without additional hardware as it is equipped with four MPPT converters featuring eight solar panel input channels. These have a wide range of input voltages (2.6 – 18 V) for reliable and flexible power distribution.
Each MPPT converter is integrated with Maximum Power Point Tracking capability for high, constant and efficient energy harvesting. The integrated ideal diodes minimize the voltage drop to 20 mV, hence increasing the circuit efficiency and removing the need of Schottky diodes on the solar panels.
Designed to offer simple, energy-saving, and low-cost EPS performance. The PC104 standard device weighs 130g and has a supply voltage of 3.3V/5V. The power supply is based on the CubeSat Kit Bus standard and has a storage level of 3350mAh(BOL).
The EPS portfolio of Terma
Terma manufactures a wide array of EPS systems and associated products to meet different mission and application needs. The portfolio consists of various modules and ancillary sub-systems to deal with different aspects of the EPS function - a selection of products are detailed below and you can see the fuller portfolio here:
The Modular Medium Power Unit - A power unit designed for observation, navigation, science or low power communication spacecrafts. The design concept was qualified by it first application in Rosetta and has been reused in Mars Express, Venus Express, Galileo and Small Geo.
The Array Power Regulation Module - The APR module consists of a power regulator function supported by a Maximum Power Point Tracker capability. The design is targeted at any type of solar array technology.
The Battery C/D Regulation Module - the BCDR module consists of two power regulators, a Battery Charge Regulator (BCR) and a Battery Discharge Regulator (BDR). The design is targeted at Li-Ion battery systems, for systems requiring a regulated 28V power bus.
The Battery Discharge Regulator Module - For systems requiring a regulated 50 volt power bus a unique Battery Discharge Regulator (BDR) module can be provided. The BDR module consists of a power regulator and a cell balancing function. The design is targeted at Li-Ion battery systems. On demand the BDR provides a regulated discharge power to the bus until the battery End Of Discharge (EOD) voltage is reached.
The Equipment Power Distribution Module - For distribution of bus power to spacecraft equipment an Equipment Power Distribution (EPD) Module is available. The module provides sixteen Latching Current Limiters (LCL) that can be configured to individual load current classes. Each switch function can be commanded on / off via a dual command and monitoring bus, distributed by a backplane interface.
The EPS portfolio of AAC Clyde Space
Starbuck Mini - a modular microsatellite PCDU (Power Conditioning and Distribution Unit) concept with focus on high reliability, resiliency and performance. The Starbuck Mini is scalable depending on the features and interface requirements of the specific mission. It provides high power 28V output and redundancy for power distribution as well as command and control via CAN or RS485.
Starbuck Nano - powerful electrical power systems that support platform sizes from 1U up to 12U, optimized for Low Earth Orbit (LEO). Each of the power systems are specialized for platform and solar panel size. The Starbuck-Nano range can support both body mounted as well as deployable solar panel configurations and supports Lithium Polymer Battery configurations.
Starbuck Micro - initially developed under a Swedish national mission and tailored to the requirements of the LEO microsatellite bus InnoSat. This is a state-of-the-art spacecraft architecture designed for innovative low cost research missions. The flexible and modular PCDU is designed for mission life of up to five years in LEO and implements both power conditioning and distribution of the regulated 28V battery bus as well an auxiliary isolated 5V bus.
The iEPS Electrical Power System and Modular Electrical Power System by Innovative Solutions In Space B.V. (ISIS)
The iEPS Electrical Power System is an off-the-shelf Electrical Power System available in three standard configurations (Type A/B/C), ideal for powering 1U – 3U Cubesats. It leverages wide bandgap semiconductor technologies, implementing GaN-FETs to improve solar power conversion efficiency and performance. The product is also equipped with an integrated heater, hardware-based Maximum Power Point Tracking (MPPT) and hardware voltage and over-current protection.
The Modular Electrical Power System is designed as a flexible EPS targeting larger nano-satellites and microsatellites from 3U upwards. Using recent high-performance technology, the EPS provides improved efficiency over the previous version while minimizing EMI. The modular architecture allows the EPS to be tailored to the needs of the platform without needing customization.
The Nova PCDU by Bradford Space
Bradford Space / Deep Space Industries Nova PCDU is a power conditioning and distribution unit that has been specifically designed for spacecraft travelling beyond earth orbit. It is characterized by a high specific performance with 2 independent 100W regulated lines, a 5—50V bus, solar array MPPT and battery management. The product also features 10 fully protected and telemetered output channels operating at up to 150W each that enable high-power sub-systems such as electrical propulsion or rover drive systems.
The Nova PCDU is just 300g and fits in a 0.4U package. Due to the system’s modular and stackable connector it can be expanded to add new features and is scalable to increase performance according to the need of spacecraft. If needed, modules may also be duplicated to provide full dual-string redundancy - all without additional NRE.
The SatRevolution EPS module is responsible for performing energy harvesting, energy storage and energy distribution to other modules under controlled conditions to provide safety and proper operation of whole satellite.
The system can support a wide range of solar panel configurations and includes the cooperation with up to two 3S Li-ion battery packs. It also includes a battery supervisory circuit and features system redundancy, autonomous fault handling and recovery.
The NART EPS is designed to provide excellent life cycle, depth of discharge, efficiency and reliability. Super capacitors provide high life cycle and robust thermal operating envelopes when compared to some alternative battery options.
The is user-friendly and has different options for development and flight models, allowing users to conveniently develop and launch their satellite on a cost- and time-effective manner. The system’s components used on the system are selected from previous missions and/or thoroughly tested on TVAC to ensure best performance and high reliability on orbit.
Ibeos’ 150 Watt SmallSat Electric Power Subsystem (EPS) is designed to be a radiation-tolerant, flexible peak power tracking solution that is capable of efficient solar array power conversion and battery charging. The EPS card provides regulated 3.3V, 5V, and 12V power, as well as unregulated battery power through switched and un-switched, current-limited outputs. The system accepts commands and provides telemetry via SPI and I2C interfaces. It also includes battery under/over-voltage and over-current protection in addition to a configurable watchdog timer for spacecraft loads.
The Aphelion Cubesat Bus Module is an integrated electrical power system and on-board computer (OBC) solution designed for mission-critical, volume-constrained environments. By consolidating both the OBC and the EPS into a single integrated unit the system aims to offer mass and volume savings while simplifying system design.
A comprehensive EPS designed to offer efficient charging capabilities in combination with integrated three-level FDIR policy. It includes an Analogue Maximum Power Point Tracking algorithm designed for reliability, performance under dynamic conditions and high efficiency.
It also features a cutting-edge analogue battery balancing unit designed to achieve optimum battery charging in order to significantly extend the batteries’ life-time. The NANOeps provides fully controlled and monitored regulated power rails to the satellite sub-systems. The integrated data handling provides system-level FDIR and full control via the hot redundant CAN interface and the Direct Command Interface.
The OrbiCraft-Pro power supply system uses the Sputnix power supply unit SXC-PSU-03 module for power control in assistance with SXC-BAT-03 battery unit for energy storage, and up to 14 solar panels as the electrical energy source.
An external battery charging rail is presented on a PC/104 connector and is typically traced to a USB connector on the front of satellite service panel. Battery module data exchange uses a dedicated interface and the OrbiCraft-Pro battery unit SXC-BAT-03 provides electrical power storage with basic protections and sensors. Power storage consists of two series Li-Ion cells with 10 Ah capacity and the board is equipped with balancing circuit.
Tailored for the needs of CubeSats, the German Orbital Systems EPS includes an autonomous lithium-ion battery charging regulator as well as a power distribution unit designed for efficient management of a satellite’s resources.
If no special requirements for computing power or redundancy are made, the system can substitute an OBC and help to reduce the overall mission costs. The system is powered by up to six solar arrays and is compatible with the CubeSat Kit specifications.
The 3u cPCI Power Supply EPS can produce a power of 77 Watts regulated output at an efficiency of greater than 80%. The device has a redesigned input filter for improved fundamental and Common Mode rejection to meet MIL-STD 461E conducted EMI.
A power supply module designed for micro/nano/Cube satellite platforms. The EPS derives its input power from two solar panels and consists of a solar panel interface, battery interface, battery charge/discharge regulator, voltage regulators and distribution electronics. The EPS generates power by means of solar cells and stores the energy in batteries, regulates the battery voltage and distributes it to the load.
The main function of the EPS is to keep the satellite powered during the eclipse period and maintain the battery in charged condition during the sunlit period. It manages the load along with the Power Distribution Module (PDM) by powering ON/OFF the on-board electronic systems to avoid unnecessary power consumption during the satellite’s normal operation.
The linear EPS provides regulated +5V and +3.3V power and unregulated battery power (6 - 8.2Vdc) to modules compatible with the CubeSat Kit Bus from two (normal-capacity configuration) or four (high-capacity configuration) 3.7V Li-Po cells.
Each cell is a standard 1st- and 2nd-generation iPodÆ battery. Each battery consists of two cells, operated in series when discharging (i.e. supplying power to the CubeSat Kit bus) and in parallel when charging. Up to two batteries can be operated in parallel and non-latching relays are used to switch the cells between the series and parallel configurations. Two independent battery chargers each charge one cell (normal-capacity configuration) or two parallel-connected cells (high-capacity configuration) when operating in the charging mode.
The P1U “Vasik” by Crystalspace
The Crystalspace P1U power supply is a very small EPS system designed to offer high performance. It suits densely packed 1U and 2U CubeSats and uses fast maximum power point tracking boost converters to charge the integrated doubled battery pack. Battery output is fed through duplicated converters that can provide 3.3V, 5V, or 12V.
The VPCDU-1 by Vectronic Aerospace GmbH
A highly integrated device to control the power supply of a small satellite’s sub-systems. The VPCDU incorporates interfaces to solar arrays and batteries, and power outlets to the satellite’s sub-systems. It also features functionalities for separation detection micro switches, under voltage lookout, battery handling and power conditioning.
The power outlets that connect to the satellite’s sub-systems are equipped with resettable electronic fuses to prevent the system from damage in case of an overload or the malfunction of external devices. Most of the internal functions are controlled by a microprocessor unit in redundant configuration.
Magellan has developed power supplies for more than 120 sub-orbital payloads since the early 1970s. The modular “by the slice” architecture of Magellan PCUs allows customers to select the mission-specific functionality and level of redundancy (single- or dual-string) required. This enables the optimization of mass, power, and volume. Magellan offers flexible and high-reliability PCU solutions for many different mission requirements, from government flagship-class spacecraft to commercial megaconstellations.
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