AC Servo Motors and Drives

Tonghang has designed and developed a new servo drive system for motor control, presenting the system's hardware and software design and implementation solutions.

1. Servo Controller Circuit Structure

Based on the main control chip of a DSP-based fully digital motor controller, the entire controller primarily consists of the following components: an IPM drive unit, a voltage and current detection and regulation unit, a DSP core circuit control unit, a DSP and communication interface unit, a power supply selection circuit, and a fault detection unit. The servo drive and DSP control chip, acting as the main control chip, execute the complex motor control algorithms and are responsible for communication with the host computer. They also have comprehensive fault detection and handling mechanisms.

The design of the hardware circuits focuses on practicality and reliability, adhering to the following basic principles:

1) Excellent reliability.
2) Meeting the needs of most users, ensuring simple installation, easy debugging, smooth operation, and simplified maintenance.
3) Reducing production costs and lead times while ensuring the proper functioning and performance of all system functions.

When initially designing the hardware circuits, one of the most pressing challenges is electromagnetic compatibility. If this issue is only addressed during experimental testing, addressing it can be time-consuming, technically complex, and even require redesigning the entire system. Electromagnetic compatibility encompasses two major issues: radiation and interference immunity. Tonghang AC Servo Motors and Drives addresses this by increasing isolation. A two-stage transformer is used between the grid and the rectifier, with copper shielding covering the primary and secondary windings to reduce electromagnetic interference and radiation at the power supply source. Interference on the I/O channels is addressed by twisted-pair cabling and optical isolation.

2 Servo Drive Control Principles

Tonghang servo drives can modify parameters in a variety of control modes. The entire drive control process is handled by software, employing closed-loop control strategies for current, speed, and position. This improves the drive's robustness and enhances the system's self-regulation capabilities. This drive can be used in permanent magnet synchronous motors with varying parameter requirements and can also meet control systems requiring high responsiveness and precision, such as CNC machine tools, printing machinery, packaging machinery, papermaking machinery, textile machinery, industrial robots, and automated production lines. It offers a variety of control modes:

1) Position Control: Based on DSP instructions enable accurate motor positioning.

2) External analog speed control: The driver parameters are set according to external analog instructions to control the motor speed, including the speed and direction of rotation.
3) External analog torque control: The driver parameters are set according to external analog instructions to control the motor torque.
4) Internal speed control: Switches between four speed modes based on the status of the input signals "Internal Speed ​​Selection 1, 2."
5) Manual control: Manually change the motor speed based on keyboard input. Driver control is entirely implemented in software. The software consists of three main aspects. The first is the main program, which performs initial system settings, such as initial motor parameter settings, module settings, and initial settings for the analog-to-digital converter module. The second is the interrupt response routine, such as the PWM interrupt response routine required when the PWM generator generates PWM waves. The third is the fault interrupt response routine. Overtemperature, overvoltage, or other system faults trigger the fault interrupt response routine to ensure normal system operation.