Maximum Power Tracking Solar Charge Controller using Microcontroller

At present, the demand of energy resources is increasing and it is very important to come up with innovative ideas to save and reduce the energy usage. There are various renewable energy sources are available like solar, wind, biomass, ocean thermal to generate an electricity for daily needs. The sun’s energy is the best option to generate an electricity and it is available everywhere in the world. Electricity from the sun can be produced through the SPV modules.

MPPT Solar Charge Controller1
MPPT Solar Charge Controller

These modules come in numerous power o/ps to meet the load requirement. Extension of power from an SPV module is of special interest as the efficiency of this module is very low. A max power tracking solar charge controller using microcontroller is used for removing the maximum power from the SPV module. A microcontroller is used to control the Maximum power point tracking algorithm which is used in PV systems to maximize the photovoltaic array o/p power.

Microcontroller based Maximum Power Tracking Solar Charge Controller

The block diagram of microcontroller based maximum power tracking solar charge controller is shown below. The block diagram is built with a PV panel, inverter, battery and charge controller. The charge controller comprises of DC-DC converter, that matches the photovoltaic module voltage to battery voltage. The current voltage and current sensors are used to sense the voltage & current to give them to a pre programmed microcontroller. This microcontroller operates at max power point by using two methods such as a perturb & observe method. The data from the pre programmed microcontroller can be diffused to the remote location via RS485 interface. This process helps to monitor and logging the data from remote area.

Solar Charge Controller using Microcontroller Block Diagram
Solar Charge Controller using Microcontroller Block Diagram

Solar Panel

A solar panel is comprised of PV cells which is used to generate & supply electrical energy for various applications such as residential, commercial, etc. There are different kinds of solar panels are available. But, in present days there are two most popular technologies are used, silicon and thin film. These two are first generation and second generation technologies.

Solar Panel
Solar Panel

Sensors

The operation of sensors in the charge controller was most important to get the desired function of the system. These sensors are used in the system for monitoring and communicating in the microcontroller.

Sensors
Sensors

DC-to-DC Converter

The DC voltage from the solar panel differs based on the intensity of the light, time and temperature of the panel. This converter is used to increase or decrease the voltage of the i/p panel to the necessary battery level. Boost converter is a powerful converter, where the DC i/p voltage of this converter is less than the DC o/p voltage. That means the PV i/p voltage is less than the battery voltage in the system. Buck converter is a powerful converter, where the DC i/p voltage is greater than the DC o/p voltage. That means the PV i/p voltage is greater than the voltage of the battery in the system.

DC-to-DC Converter
DC-to-DC Converter

Microcontroller

The microcontroller is used to process the input and output of the entire PV system. The tasks of the microcontroller include battery charging controlling, reading sensor values, system performance monitoring. The microcontroller is programmed in such a way that, it always functions at the maximum power point.

Microcontroller
Microcontroller

Battery

The battery is used to store the energy in PV MPPT charge controller to give the power when the sun’s energy not available. The battery runs with 12V, delivers a large o/p current to handle high power loads.

Battery
Battery

Inverter

The inverter is used to convert direct current to alternating current This is the final stage in the above system. By using this device, there is an opportunity for the user to access the power which is stored in the battery.

Inverter
Inverter

RS485 Interface

The RS485 serial communication is used to communicate with the sensor and performance values to a remote computer over cables. The main advantage of RS485 is, that supports for long distance communications and several receivers may be connected to a linear network with multi drop configuration.

RS485 Interface
RS485 Interface

Working of a Maximum Power Tracking Solar Charge Controller

The PV module is the main part of the above system. Every solar panel has I-V characteristics or I-V curve. The area under this curve is almost the maximum power that a solar panel would generate if it would work at open circuit voltage or maximum voltage and short circuit current or maximum current.

MPPT is a secondary method of exploiting the efficiency at which the solar panels supply electricity in an on-grid/ off-grid scenario like charging a battery. The current, voltage, temperature levels are detected by the sensors. The DC-to-DC converter is responsible for improving the o/p voltage of the solar panel to match the necessary voltage level of the battery.

A Buck Boost converter is used as a DC-to DC converter because if the battery needs a low voltage from the solar panel, then this converter reduces the voltage. If the battery needs more voltage, then this converter increases the voltage.

Thus the use of maximum power from the solar panel is done effectively. The voltage, current and temperature of the panel & the voltage and current from the DC-to-DC converter are identified by the sensors and these are given to the pre programmed microcontroller. By using perturb and observe the methods microcontroller gives maximum output. The battery is used to charge at maximum power and that is connected to the inverter where alternating current to direct current takes place.

The AC power is used for household applications and RS485 is interfaced to the microcontroller, that helps to monitor and logging the data from the remote area.

Therefore, this is all about maximum power tracking solar charge controller using microcontroller. The MPPT solar charge controllers can be used to consume maximum power out of solar panels instead of investing in a number of panels. The RS485 interface is used to monitor the data and data logging from a remote area. Further, the proposed system can be enhanced by including wireless technology so that we can transmit the data wirelessly. Furthermore, any queries regarding MPPT solar charge controller circuit diagram, please give your feedback by commenting in the comment section below. Here is a question for you, what are the applications of MPPT technology?

Photo Credits:

2 Comments

  1. shubham chaudhary says:

    what if i want a input solar panel of max power of 3300 watt and had to charge a battery of around 2750 watt via mppt technique.
    the above prescribed method can only give a theoritical knowledge for high power handling mppt.
    kindly help me out on practical basis for such high power rating if possible.

    1. Tarun Agarwal says:

      Hi Shubham Chaudhary,
      Actually this is student level project and so we did not explain in detail or in real time.
      For customization of projects please email us on team@elprocus.com

Add Comment