Application of Measurement and Control Technology of Digital for the Power Inverter - Advanced Research on Computer Education, Simulation and Modeling - page 87

power plant investment in equipment and civil charges. Therefore, the following
general requirements 10kVA inverter efficiency to> 90%, 10kVA inverter efficiency is
more than "95%.

Second, small waveform distortion high power factor: and grid solar power plant
output to be associated with the external power grid, the inverter output waveform must
be consistent with the external power grid. Requirements of the waveform distortion
<5%, high harmonic content of "3%, power factor close to 1. Independent inverter solar
power stations can be larger waveform distortion (<10%), but, in order to reduce
transmission line losses, and hope the waveform close to sinusoidal, power factor close
to 1, to reduce reactive power consumption [3], [4].
Third, the use of high: the majority required for stand-alone solar power plants in
remote mountainous areas and islands, requiring the inverter can withstand relatively
harsh conditions of use, while ensuring maintenance of conditions in a small amount of
long-term work. Because most solar power plants and grid for the family, requiring a
small inverter electromagnetic interference, does not affect people's living
environment, does not prevent the normal operation of other appliances.

3.2 Uninterruptible Power Supply UPS Inverter Characteristics

Off-line UPS in the inverter, a small power (5kVA below) mainly, as shown in Figure
2. Mainly mains filtering, voltage adjustment, in order to provide a more stable load
voltage, through the charger into chemical energy into electrical energy stored in the
battery, the event of a power interruption, the grid voltage or grid frequency is outside
the inverter input range can be in a very short time (few ms) opened its reserve power,
power to the load, the inverter is characterized by such a high conversion efficiency,
easy maintenance and low prices, for the vast majority of small and medium-power
users power protection choice.

Rectifier Rectifier

Inverter Inverter

Output Output

Charger Charger Battery Battery

Detector Detector

Fig. 2. UPS inverter

In-line UPS to the power inverter (5kVA and above) the main inverter is always in
working condition, and electrical equipment to run, in the power supply's main function
is to state regulation and to prevent voltage fluctuations and interference, to avoid
low-quality long-term electricity load has been an infringement, once the electricity
interruption, the inverter will use the machine provided by the battery power to