How To Define a Solar Inverter by waveform?
Mar 11,2023 | Daxtromn power
There are various ways to classify photovoltaic inverters. According to different waveform modulation methods, they can be divided into square wave inverters, step wave inverters, sine wave inverters, and combined three-phase inverters.
Square wave inverters output a square wave voltage waveform. Their circuits are simple, inexpensive, and easy to implement. However, the square wave voltage contains a large amount of high-order harmonic components, which can produce additional losses in the load and cause significant interference to communication and other equipment. Square wave inverters are mostly used in small-capacity inverters with design power not exceeding a few hundred watts in the early stage.
Step wave inverters output a voltage waveform with steps, and the output waveform is close to sine wave, with a significant improvement compared to square wave and a reduced content of high-order harmonics when the number of steps reaches more than 16. However, this type of inverter often requires multiple sets of DC power supplies, and the required power switches are also numerous, which is inconvenient for photovoltaic and battery grouping. In addition, square wave inverters are prone to heat generation and internal energy loss.
Sine wave inverters have a basic sinusoidal output waveform, with minimal harmonic losses in the load, low interference to communication equipment, and high overall efficiency. However, the equipment is complex and expensive. With the advancement of power electronics and the popularization of pulse width modulation technology, large-capacity PWM-type sine wave inverters have gradually become the mainstream products.
The advantages of MPPT sine wave inverters are high conversion efficiency, the ability to connect PV in series to a very high voltage, and reduce the internal heating of photovoltaic panels with high voltage and low current. The solar PV array voltage can reach 120-450V.For the Daxtromn power Solar inverter, the MPPT solar inverter better working range is 240-360V.
The inverter is composed of a three-phase rectifier, a voltage source inverter, and a controller. Due to the particularity of the direct current power generated by the photovoltaic power generation system, the photovoltaic inverter does not require a three-phase rectifier and directly connects the DC bus of the inverter to the DC bus of the photovoltaic power generation system. To stabilize the operation of the inverter, the DC bus generally needs to be equipped with a battery. A weak control signal needs to be added to the control terminal of the inverter to continuously adjust the set frequency of the inverter, change the output power of the inverter, and achieve maximum power point tracking with the photovoltaic array. As an adjustable load, the inverter needs to be jointly controlled with the MPPT of the photovoltaic array. In the photovoltaic power generation system, motors and other dynamic loads should be equipped with inverters as much as possible to reduce the startup current impact and adjust the motor load flexibly.