What is PWM and what is MPPT chargers
Solar Charge Controllers explained – PWM VS. MPPT
What are those shortenings in solar language? And what do they mean in our everyday language?
What do those two different Solar Charge Controllers do? And what do they do differently?
So many questions and just few answers.
In order to explain all of this and understand, we are gonna need to describe those two principals much closer. Right now I can only tell you that both of them have their benefits and minor flops. Only one of them is able to take a larger Home Solar Power System on the long run. Take a look our Complete Solar Power Systems
What is PWM solar charger controller?
PWM stands for Pulse-width modulation and is a modulation technique used to encode a message into a pulsing signal. Although this modulation technique can be used to encode information for transmission, its main use is to allow the control of the power supplied to electrical devices, especially to inertial loads such as motors. In addition, PWM is one of the two principal algorithms used in photovoltaic solar battery chargers, the other being maximum power point tracking.
The PWM switching frequency has to be much higher than what would affect the load – the device that uses the power, which is to say that the resultant waveform perceived by the load must be as smooth as possible. The rate, or frequency, at which the power supply must switch can vary greatly depending on load and application.
The main advantage of PWM is that power loss in the switching devices is very low. When a switch is off there is practically no current, and when it is on and power is being transferred to the load, there is almost no voltage drop across the switch. Power loss, being the product of voltage and current, is thus in both cases close to zero. PWM also works well with digital controls, which, because of their on/off nature, can easily set the needed duty cycle.
Some machines (such as a sewing machine motor) require partial or variable power. In the past, control (such as in a sewing machine’s foot pedal) was implemented by use of a rheostat connected in series with the motor to adjust the amount of current flowing through the motor. It was an inefficient scheme, as this also wasted power as heat in the resistor element of the rheostat, but tolerable because the total power was low. While the rheostat was one of several methods of controlling power (see autotransformers and Variac for more info), a low cost and efficient power switching/adjustment method was needed. This mechanism also needed to be able to drive motors for fans, pumps and robotic servos, and needed to be compact enough to interface with lamp dimmers. PWM emerged as a solution for this complex problem.
One early application of PWM was in the Sinclair X10, a 10 W audio amplifier available in kit form in the 1960s. At around the same time PWM started to be used in AC motor control.
Of note, for about a century, some variable-speed electric motors have had decent efficiency, but they were somewhat more complex than constant-speed motors, and sometimes required bulky external electrical apparatus, such as a bank of variable power resistors or rotating converters such as the Ward Leonard drive. (Source: Wikipedia)
The PWM Solar Charge Controller suites itself very well in smaller installations and in fact more suited for installations in camper cars and boats, since the power consumption vary so much and often. The PWN Solar Charge Controller or PWN Solar Power System Regulator costs often much less and proves itself efficient for many years to come. Make sure to buy the right one for your needs. Click on the picture and take a closer look at this Solar Charge Controller with automated PWM.
What is MPPT solar charger controller?
MPPT stands for Maximum Power Point Tracking and is a technique used commonly with wind turbines and photovoltaic (PV) solar systems to maximize power extraction under all conditions. PV solar systems exist in many different configurations with regard to their relationship to inverter systems, external grids, battery banks, or other electrical loads. Regardless of the ultimate destination of the solar power, though, the central problem addressed by MPPT is that the efficiency of power transfer from the solar cell depends on both the amount of sunlight falling on the solar panels and the electrical characteristics of the load. As the amount of sunlight varies, the load characteristic that gives the highest power transfer efficiency changes, so that the efficiency of the system is optimized when the load characteristic changes to keep the power transfer at highest efficiency. This load characteristic is called the maximum power point and MPPT is the process of finding this point and keeping the load characteristic there. Electrical circuits can be designed to present arbitrary loads to the photovoltaic cells and then convert the voltage, current, or frequency to suit other devices or systems, and MPPT solves the problem of choosing the best load to be presented to the cells in order to get the most usable power out.
Solar cells have a complex relationship between temperature and total resistance that produces a non-linear output efficiency which can be analyzed based on the I-V curve. It is the purpose of the MPPT system to sample the output of the PV cells and apply the proper resistance (load) to obtain maximum power for any given environmental conditions. MPPT devices are typically integrated into an electric power converter system that provides voltage or current conversion, filtering, and regulation for driving various loads, including power grids, batteries, or motors. (Source: Wikipedia)
Since the power consumption in bigger Solar Power installations requires far more consistency to fulfill the needs of the consumer, the system has to work differently in order to deliver this kind of power. An MPPT Solar Charge Controller making sure that every possible amount of power is extracted and delivered to the end station. Solar Power System Regulator which is running on MPPT, costs more than PWM solar controller and mostly used regulating power extraction at Solar Power Systems in private homes and bigger installations.
A MPPT Solar Charge Controller getting sun energy from behind the clouds far more efficient than a PWM Solar Controller.
If you are looking for a solar charger controller for your car or boat or some other vehicle of your choice – buy a PWM Solar Charge Controller. If you are thinking to go off grid, less off grid or just to save some money running your own Solar Power System at home – you will need an MPPT Solar Charge Controller.
Now you may have an idea of What is PWM and what is MPPT chargers controllers and where is the difference between them.
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What is PWM and what is MPPT chargers