Circuit Design of Frequency Conversion Control of Three-Phase DC Brushless Motor Based on FPGA

Project and feasibility analysis

Project Name: Circuit Design of Ocean Fishing Device Based on FPGA for Three-Phase DC Brushless Motor Variable Frequency Control

Main contents of the project: The ocean fishing device should have the function of automatically adjusting to the acceleration or deceleration state according to the size of the squid during the actual operation, and have the ability to measure the length of the fishing line to realize when the fishing line is fully rolled up. The function of the fishing machine automatically stops.

This project adopts FPGA to control three-phase DC motor. The EAB can be used to form the control waveform data table needed to store the current of each phase of the motor and the digital comparator designed by FPGA can synchronously generate multiple PWM current waveforms. Flexible control to meet the needs of offshore fishing equipment in the actual operation process.

Innovative: Using XLINX's FPGA, power device intelligent module IPM PS21865 and Hall sensing position detection to achieve DC brushless motor drive and speed regulation, DC brushless motor BLDC uses electronic commutator instead of traditional DC motor The mechanical reversing device overcomes the disadvantages of noise, sparks, electromagnetic interference and short life caused by brushes and commutators. The DC brushless motor has the advantages of simple structure, reliable operation and convenient maintenance of the AC motor. These control with traditional single-chip microcomputer and DSP are difficult to achieve the same control effect.

Practicality: Using FPGA to realize multi-channel PWM control, no need for external D/A converter, greatly simplifying peripheral control circuit, simple control method, high control precision and good control effect; controller adopts general-purpose microcontroller AT89S51, mature technology ,low cost.

Achievability:

The FPGA module design acquires the stored PWM waveform data by querying the ROM, and then generates a corresponding PWM waveform output via a digital comparator. After receiving the command sent by the controller AT89S51 module, the FPGA module obtains different PWM waveform data by controlling the address counter, and can output the control signals of the rotation direction, the rotation speed, and the working/stop state of the three-phase DC motor.

The IPM module performs power amplification on the control signal output from the FPGA module, thereby achieving control of the speed of the three-phase DC motor. At the same time, the IPM module will also return the overload protection and error protection signal of the three-phase DC motor to the controller AT89S51 module. After receiving the overload protection and error protection signal, the controller module will issue an abort command to the FPGA module, and the FPGA module will terminate according to the command. The operation of the three-phase DC motor protects the motor.

Project implementation plan

Basic structure of the plan

Figure 3-1

Program description

At present, the power control of ocean fishing equipment equipped with most ocean-going fishing vessels is still based on the conventional steady output mode, that is, the signal of the power control motor is stable to achieve uniform speed control of the fishing line device. In the actual application process, many problems are exposed. The traditional control method can not automatically deal with some special situations. For example, the sudden increase of the number of fish caught causes the fishing machine to be overloaded, or the fishing device is unloaded due to falling off, and the fishing line device has been recycled. The motor can't stop automatically. At this time, it is impossible to control the power output of the motor in time, which is very prone to accidents. Therefore, the problem of motor frequency conversion and control needs to be solved in time. Our team members plan to use FPGA technology to design a three-phase DC brushless motor inverter controlled ocean fishing device circuit. In order to achieve flexible and intelligent control of the fishing line device, in response to special circumstances.