Today's solar inverter layout needs based on current sensor compact , low-cost and reliable ground current detection scheme . LEM whereby specially designed CT series sensors. 24v power inverter They are rated in the range of 100mA, 200mA and 400mA different current devices provide linear output 5 volts at rated current . At 80 % and 90 % of the rated current conditions , the response time of less than 20 milliseconds and 60 milliseconds. Using high-tech design ( " flux gate " ) is the key to accurately measure small dc or ac current especially under conditions of low offset or drift ; measure DC and AC currents up to 18 kHz . CT can be mounted on a PCB, the small size, light weight, there is a through hole for passing through the phase line . Mounted on the PCB CAS / CASR / CKSR closed-loop current sensor with the same flux gate technology ; can be isolated AC and DC current measurement , they cover the range of 6 to 50Arms rated , the highest rating of three times the value of the measurement , same frequency up to 300 kHz (+ /-3dB). According to the latest requirements of the inverter design trends they were specifically designed to improve the performance of the following areas: common mode interference , temperature drift ( offset and gain ; Depending on the model , the maximum zero temperature drift of 7 to 30ppm / K), the response time ( less than 0.3 sec ) , the insulation level of the +5 volt supply and 3000w solar inverter compact size .
In order to synchronize with the grid , need special control output of the inverter . AC output sine inverter must , so to minimize harmonics , while the current changes to respond quickly to the side of the grid . There must be a sensor using the fast response time and low zero drift. Reduced zero drift caused by temperature changes will also help reduce the need for complex compensation algorithms . In contrast, the sensor monitor MPPT inverter DC input current becomes less appropriate , thus low-cost open- loop sensors .
No access to the grid inverters, such as a rechargeable battery backup system , free from the national grid , but must comply with many of the same safety and efficiency requirements.
PV inverter design must comply with the specifications are likely to become more stringent. For example , the DC input power and limitations as may be allowed to reach some consensus on the level of total harmonic inverter output current ; currently exists with a variety of local restrictions based on the layout solar inverters of the case . This requires accurate measurement of current is much higher than at 50 or 60 Hz mains frequency.
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