Main technical performance of inverter
1. rated output voltage
It represents the rated voltage that the inverter should be able to output within the allowable fluctuation range of input DC voltage. The stability and accuracy of output voltage rating are generally as follows:
(1) During steady-state operation, the range of voltage fluctuation should be limited, for example, the deviation should not exceed (+) 3% or (+) 5% of the rated value.
(2) When the load changes suddenly (rated load 0%50%100%) or other disturbance factors affect the dynamic situation, the output voltage deviation should not exceed the rated value of (+) 8% or (+) 10%.
2. The imbalance of output voltage.
Under normal operating conditions, the three-phase voltage unbalance (the ratio of the inverse component to the positive component) of the inverter output should not exceed a specified value, generally expressed as% such as 5% or 8%.
3. Waveform distortion of output voltage.
When the output voltage of the inverter is sinusoidal, the maximum allowable waveform distortion (or harmonic content) should be specified. Usually expressed as the total waveform distortion of the output voltage, its value should not exceed 5% (single-phase output allowed 10%).
4, rated output frequency
Inverter output AC voltage frequency should be a relatively stable value, usually power frequency 50Hz. Under normal working conditions, the deviation should be within 1%.
5. Load power factor
It shows the ability of inverter to carry inductive load or capacitive load. Under sinusoidal wave condition, the load power factor is 0.7-0.9 (lag), and the rated value is 0.9.
6. Rated output current (or rated output capacity).
Represents the rated output current of the inverter within the specified load power factor range. Some inverter products give the rated output capacity, whose units are represented by VA or kVA. The rated capacity of the inverter is the product of the rated output voltage and the rated output current when the output power factor is 1 (pure resistance load).
7. Rated output efficiency
The efficiency of the inverter is expressed by the ratio of the output power to the input power in the specified operating conditions. The efficiency of the inverter at rated output capacity is full load efficiency, and the efficiency at 10% rated output capacity is low load efficiency.
(1) Overvoltage protection: For the inverter without voltage stability measures, there should be output overvoltage protection measures to protect the negative intercept from the damage of output overvoltage.
(2) Over-current protection: Over-current protection of inverter should be able to ensure timely action when load short-circuit or current exceeds the allowable value, so as to avoid the damage of inrush current.
9, starting characteristics
It shows the ability of the inverter to start with load and the performance of dynamic working. Inverter should ensure reliable starting at rated load.
Noise is produced by transformer, filter inductance, electromagnetic switch and fan in power electronic equipment. When the inverter is running normally, its noise should not exceed 80 dB, and the noise of small inverter should not exceed 65 dB.