The overall structure of the DC motor control system uses the TI TMS320LF2407 DSP chip evaluation development board (EVM) as the control core, supplemented by corresponding peripheral interface circuits, including current detection modules, fault protection modules, and drive modules. The basic idea of ​​the entire system is to utilize the DSP's internal resources to generate controllable pulses to control the rectified voltage, thereby changing the electromagnetic torque of the DC motor connected in series with the main circuit and achieving motor speed regulation. The DSP is a general-purpose signal processor that uses software to implement data processing. Its algorithms are flexible and powerful, capable of meeting the requirements of large computational loads and high processing speeds. These advantages of the DSP2000 series make it the best chip for motor control systems. Control System Hardware Design Power Drive Circuit Design: To meet the needs of the electrode's rapid forward and backward bidirectional movement during processing, the driving force generated by the driver must be able to change direction. This requires that, under the condition of a constant magnetic field direction, currents in both directions can flow through the coil. The power drive circuit must be an H-type bridge chopper drive circuit. Therefore, this design adopts the H-type bipolar reversible PWM drive system shown in Figure 1. The front-end driver of the H-bridge uses the IR2110 from IR. The IR2110 is a dual-channel high-voltage, high-speed power MOSFET driver. The PWM pulse signal provided by the LF2407 is isolated and transformed before being applied to the control inputs HIN and LIN. The two outputs, H0 and I0, correspond to the inputs HIN and LIN. When the off-function terminal SD is low, an output signal is generated at the corresponding output terminal at the rising edge of the corresponding input. When SD is high, both the high-side and low-side output signals are simultaneously turned off, providing excellent controllability for protecting the power transistor and the motor. The power switching device used is the IR F640 power MOSFET from IR. [align=center] Figure 1 H-type power drive circuit[/align] Current detection loop design: The current loop forms armature current negative feedback. Its main purpose is to generate an appropriate current reference value within the allowable range to reduce the impact of power supply voltage fluctuations, load effects, and inertia changes, enabling the system to start and brake with constant current. Simultaneously, if the current detection value exceeds the maximum allowable value, an interrupt will be generated, calling the overcurrent protection program and shutting down the PWM output. However, current acquisition must consider frequency. The control frequency of the current loop in this system is equal to the carrier frequency of the PWM signal, meaning the current loop is controlled once per PWM cycle. The current detection interface circuit is shown in Figure 2. [align=center] Figure 2 Current Detection Circuit[/align] The current detection interface circuit consists of a voltage sampling circuit, a filtering circuit, an amplification circuit, a voltage offset circuit, and a protection circuit. The small current signal output by the Hall current sensor is converted into a voltage signal by the voltage sampling circuit, and then amplified by the filtering and amplification circuits. Meanwhile, since the current in the armature winding can be positive or negative, the current output by the sensor also has positive and negative values, which in turn translates to two voltage values. To meet the unipolar input voltage requirement of the LF2407A's A/D sampling port, the voltage signal must undergo voltage offset transformation. For example, the maximum starting current of the DC motor in this system is 14A. When i = 4A, the corresponding A/D input is 3.3V; when i = -4A, the corresponding A/D input is 0V; and when i = 0A, the corresponding A/D input is 1.65V. This is to convert the current feedback signal with positive and negative polarities into a unipolar voltage signal input to the LF2407's ADC unit. The two diodes D8 and D9 have a protection function to limit the input voltage. For real-time monitoring of the lower-level machine's operating status, a communication circuit module between the upper and lower-level machines is also designed. The serial communication interface of the TMS320LF2407 and the RS-232 serial port are used for asynchronous communication between the DSP and the PC. The host computer (PC) can communicate with the slave computer (DSP) via its serial port to exchange data and effectively achieve monitoring. Since the RS-232C level of the host computer and the TTL level of the slave computer are inconsistent, this paper uses a level conversion chip MAX232 for serial communication. Furthermore, since the TMS320LF2407 used in this paper is a low-power chip powered by +3.3V, a level matching circuit is required between the MAX232 and the TMS320LF2407. The interface circuit is shown in Figure 3. [align=center] Figure 3 TMS320LF2407 Serial Communication Interface Circuit[/align] Control System Software Design The software structure of the entire system includes a main program module, an initialization subroutine module, and an interrupt service routine module. The main program module mainly includes a keyboard scanning module and a display module. The function of the initialization subroutine module is mainly to set various registers, ensure the system operates normally according to design requirements, and initialize various variables. The main program primarily calls the initialization subroutine to initialize the system and start the timers used in the system. Then, it enters a loop to check the keyboard status, call the display subroutine, and wait for a system interrupt. When an interrupt occurs, the interrupt service routine is executed first, where system control is completed. The interrupt service routine module includes an A/D sampling module, an interrupt capture module, a control algorithm module, a PWM signal output module, and a serial communication module with the host computer. In the serial port interrupt, information transmission with the host is mainly completed, current operating status is fed back, and the motor is started or stopped according to the host's commands. The ADC interrupt occurs a period of time after each PWM cycle. The current phase current value can be calculated from the A/D conversion value for current loop adjustment. After a set number of current loop adjustments, a speed loop adjustment is performed to ensure the system operates as required. In conclusion, DSPs have many dedicated peripherals and high-performance characteristics, making them one of the best chips for motor control systems. With the continuous improvement of DSP control capabilities, they will replace microcontrollers in motor control and achieve tremendous development. This paper introduces the application scheme of DSP in the servo control system of permanent magnet brushless DC motor from both hardware and software perspectives. The hardware platform provided can realize the evaluation of many modern control theories and algorithms; on the software side, it provides the implementation method of DSP in motor control, which has a wide range of application value.