The rapid development of power electronics has made various power engineering electronic systems increasingly common in industrial production, road transportation, and home use, and the harmonic current damage generated by these discrete system loads is also becoming increasingly serious. Harmonic current causes harmonic current consumption of components in the power grid, reduces the power factor of machine equipment, and even harms electrical equipment such as capacitors; Harmonic currents harm instruments and adjacent communication systems, making them unable to function properly.
The frequency and size of harmonic currents in the power supply system change with the load of the system software. Choosing a traditional LC static data filter cannot meet the requirements. However, adopting an active power filter cabinet in power engineering can dynamically compensate for the harmonic currents and reactive power that change in size and frequency. Therefore, the exploration and use of active power filter cabinets are increasingly receiving high attention from everyone. The basic principle of an active filter cabinet is to first detect harmonics from the compensation target, and then the compensation device creates a compensation current flow that is the same size as the harmonic but has the opposite phase difference. The two offset each other, resulting in only the fundamental component in the current flow of the power grid. The control board is a key component of the active power filter cabinet, which controls the personal behavior of the active power filter cabinet based on the single pulse that causes and manipulates the power switch components to dynamically compensate for harmonic current and reactive power.
The Structural Characteristics and Basic Elements of Automatic Control Systems
(1) Personal behavior of manipulating the active filter cabinet
Manipulate the output voltage of the inverter power supply based on the harmonic current and active current components of the verified load current, so that the compensation flow rate exported by the active filter cabinet is offset by the sum of the load harmonic and active flow rate. Therefore, the system software current is the fundamental positive sequence active power rate flow rate.
(2) Causing the opening of a single pulse
By manipulating the on/off and on/off of IGBT through the optocoupler circuit, PWM opens a single pulse, enabling the active filter cabinet to export an appropriate amount of harmonic compensation current.
(3) Single pulse synchronization
Based on the single pulse taken back from the power grid, a differential signal synchronized with the grid voltage is generated to maintain the working voltage exported by the active filter cabinet in step with the grid voltage.
(4) Function of self fault tolerance mechanism
Once there are errors in some components of the control board itself (such as the disconnection of the transformer (PT)), the control board can immediately generate unknown errors and alarm, while avoiding equipment withdrawal from operation. Common faults can be easily repaired after repair.
(5) Maintenance function
When the active filter cabinet operates under load or other abnormal conditions, and the electrical flow rate does not exceed the guarantee.
Alright, that's all for today's explanation. If you need an active filter cabinet, you can contact our manufacturer.