The development of driver technology has evolved from a situation where foreign countries dominated to the emergence of various excellent technologies in China. This demonstrates the progress of domestic technology and also shows that each technological innovation brings about several market revolutions led by high-end technologies.
1. Constant voltage drive
Single-voltage drive refers to supplying power to the motor windings using only a voltage in one direction during operation, with multiple windings alternately providing voltage. This is a relatively old drive method and is now rarely used.
Advantages: The circuit is simple, with few components and easy control, making it relatively easy to implement.
Disadvantages: A transistor with a sufficiently large current supply is required for switching; the stepper motor operates at a relatively low speed; the motor vibrates significantly; and it generates a lot of heat. Since it is no longer in use, it will not be described in detail.
2. High and low voltage drive
Due to the numerous drawbacks of constant voltage drive, further technological advancements have led to the development of new high- and low-voltage drives to address some of the shortcomings of constant voltage drive. The principle of high- and low-voltage drive is to use high voltage control when the motor moves to a full step, low voltage control when it moves to a half step, and low voltage control when it stops.
Advantages: High and low voltage control improves vibration and noise to some extent, introduces the concept of microstepping control for stepper motors for the first time, and also introduces a working mode in which the current is halved when stopped.
Disadvantages: The circuit is more complex than constant voltage drive, the requirements for the high frequency characteristics of transistors are higher, the motor still vibrates a lot at low speeds, and the heat generation is still relatively large. This drive mode is basically not used now.
3. Self-excited constant current chopper drive
The working principle of the self-excited constant current chopper drive is that when the current reaches a certain set value, the current is turned off by the hardware, and then another winding is energized. When the current of the other winding reaches a certain fixed current, it can be turned off by the hardware again. This process is repeated to drive the stepper motor.
Advantages: Noise is greatly reduced, speed is increased to some extent, and performance is improved compared to the previous two types.
Disadvantages: It requires high-level circuit design and strong anti-interference capabilities. It is prone to high-frequency interference, which can burn out driving components. It also requires high-performance components.
4. Current comparison chopper drive (the main technology currently used in the market)
The current comparison chopper drive converts the stepper motor winding current value into a certain proportion of voltage, compares it with the preset value output by the D/A converter, and controls the switching of the power transistor based on the comparison result, thereby achieving the purpose of controlling the winding phase current.
Advantages: It enables motion control to simulate the characteristics of a sine wave, greatly improving performance. The motion speed and noise are relatively low, and higher subdivision can be used. It is a currently popular control method.
Disadvantages: The circuit is relatively complex, and it is difficult to control the interference in the circuit to match the theoretical requirements. It is prone to jitter. In controlling the formation of the peaks and troughs of the sine wave, it is easy to cause high-frequency interference, which in turn causes the driving components to overheat or age due to excessive frequency. This is also the main reason why many drivers are prone to red light protection after more than a year of use.
5. Submersible drive
This is a brand-new motion control technology. It's an innovative driving method that overcomes the shortcomings of current current comparison chopper drive technology. Its core technology adds heat dissipation and high-frequency suppression protection to the drive components, building upon the current comparison chopper drive.
Advantages: In addition to the advantages of current comparison chopper drive, it generates very little heat and has a long service life.
Disadvantages: It's a brand new technology, so the price is relatively high. Currently, the matching requirements for each stepper motor and driver are relatively strict.
