Small power devices have integrated more and more new technologies. Such as switching power supply, hard switching, soft switching, voltage regulator, linear feedback regulator, magnetic amplifier technology, CNC regulator, PWM, SPWM, electromagnetic compatibility and so on. The actual demand directly promote the continuous development and progress of power technology, in order to automatically detect and display current, and in the over-current, over-voltage and other hazardous situations with automatic protection and more advanced intelligent control, with sensing, sensing sampling, Sensing power protection technology is becoming a trend, the detection of current or voltage sensors came into being and in our country by the majority of power designers of all ages. Current sensors in the inverter control as a key component of the inverter performance protection to do some of the current failure of the inverter on the market by the current sensor damage or poor use caused. The following describes the use of current sensors in the inverter, the general supporting current sensor, the corresponding power supply ± 12V, ± 15V; conditioning circuit constitutes a current sampling module, the module will be three-phase stator current into a basic binary code, Provide current timely information, to complete the current loop adjustment. The system uses three JCE module (part of the inverter manufacturers also use two, the third only through the algorithm to complete) were detected a, b, c-phase current. And through the sampling resistance of the current information into voltage information, and then by the inverter master control chip AD conversion module into a digital signal. After digital filtering and scaling, current feedback is provided for current loop regulation. The hardware schematic diagram of the detection circuit is as follows: The JCE current sensor converts the current information into voltage information. In addition, the signal returned by the LEM is converted into a voltage range suitable for the control chip. First, the voltage signal is transformed into a symmetrical positive and negative voltage, and then the corresponding offset is provided To fit the control chip voltage range. JCE pairs of a, b, c three-phase current are sampled, the test module is stored in the appropriate register for the master control system. Usually three-wire system, three-phase motor current and zero stator, LEM components of a, b, c-phase current sampling, the detection module after the conversion results as a basis for detecting three-phase current imbalance rate; In addition, the inverter After the device cuts off the output, the three-phase current flows of a, b and c can be detected by the LEM component to determine whether the power module is reliably shut down and eliminate the potential safety hazard. In the application, JCE sensor reflects its many features: Overload ability: When the primary current overload, it can automatically protect, even if the overload current is twenty times the rated value of the sensor will not be damaged; The capacitance between the primary and the secondary is very weak, and in many applications the various effects of the mode voltage are negligible; High sensitivity: can distinguish between weak signals on high components, such as several hundred amperes of DC can distinguish a few milliamps of AC components; High reliability: the failure rate λ = 0.43 × 10-6 / h; strong anti-external magnetic field: the experiment at a distance sensor 5 ~ 250px at twice the operating current generated by magnetic interference caused by its own error ≤ 0.5% . It can measure arbitrary current waveform, such as DC, AC, pulse waveform, etc., can even measure the transient peak; The primary circuit and the secondary circuit are completely insulated with each other. The insulation withstand voltage is generally 3 to 6 kV, and the special requirement can reach 6 to 50 kV. High measurement accuracy: accuracy of better than 10% in the operating temperature range, the accuracy of any waveform measurement; Good linearity: better than 0.5% Dynamic performance is good: the response time is less than 1μs, the tracking speed di / dt is higher than 50A / μs; Working frequency bandwidth: 0% (DC) ~ 100kHZ range of accuracy can reach 1%, 0 ~ 5kHZ accuracy increased to 0.5%; Practice has proved that the JCE current sensor, conditioning circuit constituted by the current detection link, fully meet the requirements of current detection of the inverter closed-loop control. Corrugated Hose,Fuel Pump Hose,Bellows For Fuel Pump,Fuel Pump Corrugated Pipe Wenzhou Hengyi Auto Parts Co.,Ltd , https://www.autoparts-hy.com
August 10, 2024