1. Main performance characteristics of off-grid inverters
(1) It is controlled by 16-bit microcontroller or 32-bit DSP microprocessor.
(2) The solar charging adopts PWM control mode, which greatly improves the charging efficiency.
(3) Various operating parameters are displayed by digital or liquid crystal, and various fixed value parameters can be flexibly set.
(4) Square wave, correction wave, sine wave output. When the pure sine wave is output, the waveform distortion rate is generally less than 5%.
(5) The voltage regulation accuracy is high, and the output deviation is generally not more than ±3% under the rated load state.
(6) It has the function of slow start to avoid large current impact on the battery and load.
(7) High frequency transformer isolation, small size and light weight.
(8) Equipped with standard RS232/485 communication interface, which is convenient for remote communication and control.
(9) It can be used in an environment above 5500m above sea level, and the ambient temperature range is -20~50℃.
(10) It has various protection functions such as input reverse connection protection, input under-voltage protection, input over-voltage protection, output over-voltage protection, output overload protection, output short-circuit protection, and overheating protection.
2. Main performance characteristics of grid-connected inverter
(1) The power switch device adopts a new type of IPM, which greatly improves the system efficiency.
(2) The MPPT self-optimization technology is used to realize the maximum power tracking function of the solar cell to maximize the power generation of the system.
(3) LCD displays various operating parameters, user-friendly interface, and various operating parameters can be flexibly set by pressing buttons.
(4) There are a variety of communication interfaces to choose from, which can easily realize the monitoring of the host computer(The host computer refers to a computer that people can directly issue control commands, and various signal changes are displayed on the screen, such as voltage, current, water level, temperature, photovoltaic power generation, etc.)
(5) It has perfect protection circuit and high system reliability.
(6) It has a wide DC voltage input range.
(7) The parallel operation of multiple inverters can be realized, which simplifies the design of the photovoltaic power station and enables the system to expand smoothly.
(8) It has a power grid protection device and has the function of anti-islanding protection.
3. Safety performance requirements
(1) Insulation resistance. The insulation resistance between the DC input of the inverter and the chassis should be greater than or equal to 50MΩ, and the insulation resistance between the AC output of the inverter and the mechatronics should also be greater than or equal to 50MΩ.
(2) Dielectric strength. The DC input of the inverter and the casing should be able to withstand a dielectric strength test with a frequency of 50Hz, an AC voltage of 500V sine wave, and a duration of 1min. There should be no breakdown or arcing during the test. The AC output of the inverter and the machine light should be able to withstand the dielectric strength test with a frequency of 50Hz, an AC voltage of 1500V sine wave, and a duration of 1min. There should be no breakdown or arcing during the test.