Frequency converter is a power control equipment that uses frequency conversion technology and microelectronics technology to control AC motor by changing the working power frequency of the motor. MCU, as the core component of variable frequency drive control, provides the required power supply voltage according to the actual needs of the motor. With the application of high performance microprocessor and the development of control technology, frequency converter further realizes small weight, high performance, multi-function and pollution-free.
< b> Vector frequency converter VS general frequency converterFrequency converter can be divided into general frequency converter and vector frequency converter. Vector frequency converter adopts vector control mode, which belongs to high performance control mode. It is based on the dynamic mathematical model of induction motor according to rotor flux orientation, and its control principle is similar to that of DC motor. Vector frequency converter has higher control precision and higher output torque at low speed.
In the face of high speed response requirements of the working machinery, such as industrial robots, the drive system in the speed response at least 100rad/s, vector frequency converter speed response value can reach 1000rad/s, can ensure that the robot drive system quickly and accurately work. Vector frequency converter is also generally used in heavy load starting occasions, such as high-power long belt, elevator and so on. Ordinary frequency converter is not suitable for such scenarios. Due to heavy load and insufficient output torque during startup, the motor cannot be started, and faults such as motor blockage or frequency converter overcurrent will be reported.
Vector converter application scheme of AT32 MCU
Vector frequency conversion control has large torque, stable torque output, low noise and high efficiency. However, the complex control algorithm and large amount of computation require MCU performance. AT32F421 series value ARM® is adopted as the application scheme of ATtrix vector converter The Cortex®-M4 microcontroller has a core comparable in price to the M0, a main frequency of up to 120MHz, and supports up to 64KB Flash memory (Flash) and 16KB random access memory (SRAM), providing rich interfaces and various functions to achieve high performance and high precision motor drive control.
AT32F421C8T7 as the core part of variable frequency drive control, through the control of IGBT in the converter, current sensor to achieve the purpose of energy saving, speed regulation, and to achieve the protection of the converter, such as over current, over voltage, overload protection. AT32F421 has high-speed GPIO processing response speed, as well as fast ADC conversion speed, up to 2MHz, greatly improve the response speed of the converter, can be precise control of torque, with fast system response, wide speed range, good acceleration and deceleration performance. In the torque control requirements of high occasions, with superior control performance.
< /p>At the same time, the industrial environment where the frequency converter works is faced with electromagnetic interference, corrosive gas, vibration and impact, and other tests, which requires the stability of MCU. AT32F421 supports industrial chip working temperature range of -40 ~ 105°C, can adapt to harsh working environment, such as paper machine, printing and dyeing machine are required to work in high humidity, high temperature and corrosive gas environment. Improved product reliability and environmental adaptability, more optimized functions, more flexible applications, and more stable performance.
