Inverter is the use of power semiconductor devices on and off the role of the power frequency power conversion to another frequency control device to achieve the asynchronous AC motor soft start, frequency control, improve operational accuracy, change the power factor, over-current / Over-voltage / overload protection and other functions. With the use of inverter and automatic control system, due to the different use of frequency converter and control valve, so some problems need attention and attention.
1, the frequency of the given signal should try to use 4-20mA international standard signal
Should pay attention to the shielding of the signal line ground, to avoid interference signal into the inverter. The production site has interference signals, interference signals will affect the stability of the control, so to enable the input filter, the setting range is 0.00-5.00s. If you use the inverter built-in PID function, but also enable the feedback filter to increase the stability of the built-in PID control, the setting range of 0.0-60s. However, it should be noted that the filter time is set too long, the control is stable, but the system response is poor; the filter time is set too short, the system response is fast, but the control is unstable; therefore, the filter time should be long, short Adjust.
2, to set the appropriate manual, automatic switching operation function
Optional manual, manual, forced manual function. If necessary, can also consider the current and voltage given redundant operation, that is, the inverter frequency setting signal is set by the normal use of current, abnormal voltage manually set. That is, adding a potentiometer to set the frequency of the inverter, so there will be two kinds of current signal and voltage signal for the frequency given signal of the inverter. Because there are two kinds of frequency setting signals input to the frequency converter, the redundancy is increased degree.
China's inverter market has broad space for development. With the expansion of the market and the diversification of client-side demands, the functions of domestic inverter products are constantly improving and increasing, and the integration and systematization are getting higher and higher. The use of frequency converter more widely, which also requires us to use the inverter in the field, the need to pay attention to problems and care has become more important.