Development and research of uninterruptible power supply system for networks with supply voltage up to 24 V

Abstract

Objectives. Due to the continuous rapid development of renewable energy sources, requirements for secondary power supply systems keep increasing from year to year. Productive uptime for end users is dependent on the efficiency and stability of the power supply system. Such systems should be able to distribute and store energy from renewable sources having various parameters and configurations. Therefore, the present work is aimed at developing technical solutions for efficient uninterruptible secondary power supply systems in low voltage DC networks.Methods. Advanced circuitry solutions are used for performing pulse conversions with high efficiency. The flexible hardware-software system is used for implementing the parameter control system.Results. An uninterruptible power supply for low-voltage DC networks is developed. The description of subsystems and calculations for all main elements including the power ones are given. Using a contemporary component base, the system prototype is assembled, configured, and measured by parameters. The presented solutions allow achieving the universality of the system in terms of the input and output voltage range. Support for the fast-charging Power Delivery protocol is integrated. As well as regulating the battery charging current and voltage, the Li+ battery charging controller permits changes in the number of chargeable cells. The monitoring and control unit monitors network parameters and controls the system automation. Using a microcontroller as the control device, it is possible to easily change control parameters by changing software settings. Dual redundancy of the module monitoring the built-in battery parameters is used to ensure the reliability and safety of system functioning. Support for the standardized I2C communication protocol with a separate power bus allows any necessary sensors to be connected for monitoring system parameters. External high-power devices controlled by a PWM signal may be added, if required. In the paper, the Li+ battery charging profile recommended by the manufacturer is provided.Conclusions. The designed system provides stable power supply to end users at a power consumption up to 40 W for at least 45 min. The automation demonstrates reliable operation.