DEVICE FOR CONTROLLING PARAMETERS OF ACCUMULATOR BATTERIES AND THE CORRESPONDING DIRECT CURRENT NETWORK

Abstract

Mobile devices for information, control and telemetry systems are powered by mobile generators through AC to DC converters, by batteries or, if possible, directly by solar panels. Solar panels typically work in a system that involves the usage of batteries to keep the systems running when the solar panels are not working or not providing enough power. The batteries can be recharged from the panels themselves if the solar panels have sufficient power or from an external direct current source. Also, for some mobile devices, power systems are used only with batteries, which are recharged from generators or, if possible, from standard electrical networks. All these options of power supply systems for mobile devices require operational control of battery parameters and corresponding direct current networks. The paper proposes a device for monitoring the following parameters: voltage of the direct current network from which the mobile device is powered or the batteries are charged; battery charge current control; control of insulation resistance of direct current circuits; control of the voltage of chargers; monitoring the status of chargers; protection of batteries from deep discharge; control of the state of switching nodes. The device is implemented as a two-processor system based on STM32F103 microcontrollers. A non-contact sensor of the LEM LA 100-P type is used to measure the direct current, which generates an analog signal proportional to the value of the direct current. This signal is passed to a 16- bit analog-to-digital converter. Given that these microcontrollers have integrated 12-bit analog-to- digital converters, an external 16-bit analog-to-digital converter of the ADS1115 type is used to ensure the necessary accuracy of direct current and voltage measurement, which transmits information to the basic processor via the I2C interface. The basic processor implements the main operating modes of the device, and the local processor provides information exchange with the general mobile power supply system through the RS-485 interface. The device is equipped with an indication system based on an LCD indicator of the VS1602A type and functionally programmable single LED indicators, a local keyboard for selecting control modes, a USB port for connecting additional modules and a SWD port for programming the Flash memory of microcontrollers and debugging programs in real time. During operation, parameters of non-standard events are stored in the device's non-volatile memory. The software of the basic and local processors has been developed, which ensures the functioning of the device in basic modes and performs periodic self-diagnosis of the device. The obtained results can be used in scientific research and in the design of real automated power systems for mobile information systems. Keywords: power systems of mobile information systems, batteries, battery charging, microcontroller, LCD indicator, I2C interface, USB interface, RS-485 interface, SWD interface.