PWM control is one of the simplest methods available, especially when dealing with 48V or 96V systems. The open-circuit voltage of a solar panel can often exceed 200V DC, which makes reliability an important consideration. To ensure stable operation, it's necessary to provide a separate auxiliary power supply for both the CPU and the driver circuit. This system is designed to handle charging currents ranging from 50A to 100A. Since PWM is used, the power loss on the MOSFETs is minimal, so only a small heatsink is required to keep them cool.
Here is a physical image of the setup:
In reality, this PWM control method works by switching a group of MOSFETs, similar to how a relay operates. At night, these MOSFETs turn off to prevent the battery from discharging back into the solar panel. I used the TLP250 optocoupler to drive the MOSFETs. Notably, there’s no need for a fan because the heat sink is designed to conduct heat efficiently, eliminating the need for air cooling.
The switching frequency on the MOSFETs is very low, typically below 1kHz. The MCU generates a set of PWM pulses, and the battery voltage is sampled to perform a PI adjustment. This ensures accurate regulation. In fact, the duty cycle can go up to 100%, as the optocoupler is powered separately from the main supply. At 100% duty cycle, the MOSFET acts like a direct connection between the solar panel and the battery, allowing full power transfer without any losses.
With Push-in connection technology, you can connect conductors easily – both directly and without tools, insert forces reduced by 50%. it is suitable for various applications. Insert rigid conductors or conductors with ferrules from 0.25mm² into the conductor shaft.The contact spring opens automatically and provides the required pressure force against the current bar.
When installing smaller conductors from 0.14mm², use a standard screwdriver to push the orange button and actuate the contact spring.
Push-in Connection have test and passed various certificates. For example, Vibration resistance in accordance with railway standard DINEN50155,shock and corrosion resistance in accordance with current shipbuilding registers.
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