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Main technical performance of the inverter
- Aug 07, 2018 -

Photovoltaic inverter.jpg

1. Rated output voltage

Within the allowable fluctuation range of the specified input DC voltage, it indicates the rated voltage value that the inverter should be capable of outputting. The stability accuracy of the output rated voltage value is generally as follows:

In steady state operation, the voltage fluctuation range should have a limit, for example, the deviation does not exceed ± 3% or ± 5% of the rated value.

In the case of a sudden change in load (rated load 0% → 50% → 100%) or other disturbance factors, the output voltage deviation should not exceed ± 8% or ± 10% of the rated value.

2. Unbalance of output voltage

Under normal operating conditions, the three-phase voltage imbalance of the inverter output (ratio of the reverse sequence component to the positive sequence component) should not exceed a specified value, generally expressed in %, such as 5% or 8%.

3. The waveform distortion of the output voltage

When the inverter output voltage 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 allows 10%).

4. Rated output frequency

The frequency of the inverter output AC voltage should be a relatively stable value, usually 50Hz. Under normal working conditions, the deviation should be within ±1%.

5. Load power factor

Characterizes the ability of an inverter with inductive or capacitive loads. Under sine wave conditions, the load power factor is 0.7 to 0.9 (hysteresis) and the nominal value is 0.9.

6. Rated output current (or rated output capacity)

Indicates the rated output current of the inverter within the specified load power factor range. Some inverter products give a rated output capacity, the unit of which is expressed in VA or kVA. The rated capacity of the inverter is the product of the rated output voltage as the rated output current when the output power factor is 1 (purely resistive load).

7. Rated output efficiency

The efficiency of the inverter is the ratio of its output power to input power, expressed in %, under 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.

8. Protection

Overvoltage protection: For inverters without voltage stability measures, there should be output overvoltage protection measures to protect the negative intercept from the output overvoltage.

Overcurrent protection: The overcurrent protection of the inverter should ensure that the load acts in a timely manner when the load is short-circuited or the current exceeds the allowable value, so as to protect it from inrush current.

9. Starting characteristics

Characterizes the ability of the inverter to load start and performance during dynamic operation. The inverter should be guaranteed to start reliably under rated load.

10. Noise

Transformers, filter inductors, electromagnetic switches, and fans in power electronics can generate noise. When the inverter is in normal operation, the noise should not exceed 80dB, and the noise of the small inverter should not exceed 65dB.