A newer approach to optimizing the efficiency and reliability of solar systems is the use of micro-inverters connected to each solar panel. Equipped with a separate micro-inverter for each solar panel, the system can adapt to changing load and weather conditions, providing optimum conversion efficiency for a single panel and the entire system. The micro-inverter architecture also simplifies cabling, which means lower installation costs. By making the consumer's solar power generation system more efficient, the time it takes for the system to “retract†the initial investment in solar technology will be reduced. Power inverters are key electronic components of solar power systems. In commercial applications, these components connect photovoltaic (PV) panels, batteries that store electrical energy, and local power distribution systems or utility grids. Figure 1 shows a typical solar inverter that converts very low DC voltages from the PV array output into several voltages, such as battery DC voltage, AC line voltage, and distribution grid voltage. In a typical solar energy harvesting system, multiple solar panels are connected in parallel to an inverter that converts the variable DC output from multiple photovoltaic cells into a clean 50 Hz or 60 Hz sine wave inverter. In addition, it should also be noted that the microcontroller (MCU) module TMS320C2000 or MSP430 in Figure 1 typically includes key on-chip peripherals such as pulse width modulation (PWM) modules and A/D converters. Figure 1: The traditional power conversion architecture consists of a solar inverter that receives a low DC output voltage from the PV array and produces an AC line voltage. The main goal of the design is to maximize conversion efficiency. This is a complex and iterative process involving the Maximum Power Point Tracking Algorithm (MPPT) and a real-time controller that executes the associated algorithms. Maximize power conversion efficiency Inverters that do not use the MPPT algorithm simply connect the photovoltaic module directly to the battery, forcing the photovoltaic module to operate at the battery voltage. Almost without exception, battery voltage is not the ideal value for collecting the most available solar energy. Figure 2 illustrates the typical current/voltage characteristics of a typical 75W photovoltaic module at a 25°C battery temperature. The dotted line shows the ratio of voltage (PV VOLTS) to power (PV WATTS). The solid line indicates the ratio of voltage to current (PV AMPS). As shown in Figure 2, at 12V, the output power is approximately 53W. In other words, by forcing the photovoltaic module to operate at 12V, the output power is limited to approximately 53W. However, after using the MPPT algorithm, the situation has changed radically. In this example, the voltage at which the module can achieve maximum output power is 17V. Therefore, the MPPT algorithm's job is to make the module work at 17V, so that all 75W of power can be obtained from the module regardless of the battery voltage. A high efficiency DC/DC power converter converts the 17V voltage at the input of the controller to the battery voltage at the output. Since the DC/DC converter reduces the voltage from 17V to 12V, in this example, the battery charging current in the system supporting MPPT function is: (VMODULE/VBATTERY) × IMODULE, or (17V/12V) × 4.45A = 6.30A. Assuming that the conversion efficiency of the DC/DC converter is 100%, the charging current will increase by 1.85A (or 42%). Although this example assumes that the inverter processes energy from a single solar panel, conventional systems typically have one inverter connected to multiple panels. This topology has both advantages and disadvantages depending on the application. MPPT algorithm There are three main types of MPPT algorithms: disturbance-observation, conductance increment, and constant voltage. The first two methods are often referred to as “climbing†because they are based on the fact that on the left side of the MPP, the curve is on the rise (dP/dV>0), while on the right side of the MPP, the curve is down (dP/dV <0). ). The Disturbance-Observation (P&O) method is the most commonly used. The algorithm perturbs the operating voltage in a given direction and samples dP/dV. If dP/dV is positive, the algorithm "understands" that it was just adjusting the voltage towards the MPP. Then it will always adjust the voltage in this direction until dP/dV becomes negative. P&O algorithms are easy to implement, but in steady-state operation they sometimes oscillate around the MPP. And their response speed is slow, and even in rapidly changing weather conditions it is possible to reverse the direction. The Conductance Increment (INC) method uses the conductance increment dI/dV of the photovoltaic array to calculate the positive and negative of dP/dV. INC can track rapidly changing light exposures more accurately than P&O. But like P&O, it can also oscillate and be "deceived" by rapidly changing atmospheric conditions. Another disadvantage is that the added complexity increases computation time and reduces the sampling frequency. The third method "constant pressure method" is based on the fact that, in general, VMPP/VOC ≈ 0.76. The problem with this method stems from the fact that it is necessary to instantaneously adjust the current of the photovoltaic array to zero to measure the open circuit voltage of the array. Then, the operating voltage of the array is set to 76% of the measured value. However, during the disconnection of the array, the available energy is wasted. It has also been found that although 76% of the open circuit voltage is a good approximation, it is not always consistent with MPP. Since no MPPT algorithm can successfully meet all common usage environment requirements, many design engineers will let the system first evaluate the environmental conditions and then select the algorithm that best suits the current environmental conditions. In fact, there are many MPPT algorithms available, and it is not uncommon for solar panel manufacturers to provide their own algorithms. For inexpensive controllers, in addition to the normal control functions of the MCU, executing the MPPT algorithm is no easy task. The algorithm requires these controllers to have superior computing power. Advanced 32-bit real-time microcontrollers such as the Texas Instruments C2000 platform family are suitable for a variety of solar applications. Power inverter There are many benefits to using a single inverter, the most prominent of which is simplicity and low cost. The use of MPPT algorithms and other techniques has increased the efficiency of single inverter systems, but only to a certain extent. The disadvantages of a single inverter topology can vary depending on the application. The most prominent is the reliability problem: as long as the inverter fails, the energy generated by all the panels is wasted before the inverter is repaired or replaced. Even if the inverter is working properly, a single inverter topology can have a negative impact on system efficiency. In most cases, each solar panel has different control requirements for maximum efficiency. Factors that determine the efficiency of each panel are: differences in manufacturing of photovoltaic modules contained in the panel, different ambient temperatures, shadows, and azimuths of different light intensities (received solar energy). Compared to the use of an inverter in the entire system, the provision of a micro-inverter for each solar panel in the system will again increase the conversion efficiency of the entire system. The main benefit of the micro-inverter topology is that even if one of the inverters fails, the energy conversion can still take place. Other benefits of using a micro-inverter include the ability to adjust the conversion parameters of each solar panel using high resolution PWM. Since clouds, shadows, and shadys change the output of each panel, providing each panel with a unique micro-inverter allows the system to adapt to changing load conditions. This provides the best conversion efficiency for each panel and the entire system. The micro-inverter architecture requires each panel to have a dedicated MCU to manage energy conversion. However, these additional MCUs can also be used to improve system and panel monitoring. For example, large solar farms benefit from inter-panel communication to help maintain load balancing and allow system administrators to plan in advance how much energy is available and what to do with that energy. However, to take full advantage of the benefits of system monitoring, the MCU must integrate on-chip communication peripherals (CAN, SPI, UART, etc.) to simplify interfacing with other micro-inverters in the solar array. Square Push Button,Led Push Button Switch,Push Button Illuminated Switches,Game Machine Push Button Guangzhou Ruihong Electronic Technology CO.,Ltd , https://www.callegame.com