Motors are widely used in various fields of people's work and life, such as printers, photocopiers, fax machines, projectors, refrigerators, washing machines, air conditioners, gas stoves, cameras, ATM machines, electric sewing machines, security cameras, vending machines, hot water supply systems, garden irrigation systems and industrial automation. This paper discusses the common challenges of stepper motor drive, and focuses on the introduction of energy-efficient stepper motor driver solutions for office automation equipment applications.
0 Introduction
Nowadays, more and more attention has been paid to energy saving. It is particularly important to drive motors with high energy efficiency. In terms of types, motors include AC motor, DC brushless motor, DC brushless motor, permanent magnet synchronous motor, servo motor and stepping motor. Among them, stepper motor works by pulse, also known as digital motor or pulse motor.
The rotation angle of stepper motor is proportional to the number of pulses and the speed is proportional to the frequency of pulses. It can control the rotation of stepper motor accurately by controlling the number of pulses, making it very suitable for positioning applications. This paper will discuss the common challenges of stepper motor drive, and focus on introducing a high energy efficiency stepper motor driver scheme for office automation equipment applications.
1 Common Challenges in Stepping Motor Drive Applications
Motor drivers can be used in many different applications. Design engineers face some common challenges when designing motor drivers. First, most of today's designs require motor-driven applications and related motor-driven IC and components to provide low energy consumption and high energy efficiency. For example, if the fan driver circuit board is located inside the sealed housing, it will generate heat, requiring additional energy consumption to cool it. Therefore, it is necessary to use the built-in fan in the internal circulation cold air to reduce heat and manage heat dissipation. So engineers may require low power loss, as well as powerful, energy-efficient cooling motors.
Secondly, from the end user's point of view, it is extremely necessary to reduce the noise generated by the motor in order to avoid the feeling of discomfort. Designers must also be able to compensate for any external noise or vibration in the system. Thirdly, whether due to limited living space or user preferences, high demand for compact solutions is a common consumption trend. This trend leads to a preference for smaller size and low noise motors, but it is not always possible to attempt to compensate for other design requirements.
It is noteworthy that the durability and safety of motors and motor drivers are critical because high voltage power supply is required to drive white household appliances and industrial applications. Needless to say, engineers need to choose reliable motors that can accurately control speed.
2. Working Principle of Permanent Magnet Stepping Motor and Hybrid Stepping Motor
Stepping motors are often used in precision control applications, and micro-stepping technology is used to reduce motor vibration. Figure 2 shows the working principle diagrams of permanent magnet stepper motor and hybrid stepper motor. Stepping motors work in the form of digital pulses, usually called synchronous motors or pulse motors. Stepping motors control rotation by turning on and off MOSFET.
When the current flows through the MOSFET switches OUT1 and OUT2, the position of the permanent magnet rotor is shown in the left figure. Rotor position can be controlled by controlling the current of OUT1, 2, 3 and 4. The rotation angle is proportional to the number of pulses and the speed is proportional to the frequency of pulses. You can precisely control the rotor position by controlling the number of pulses to make it suitable for positioning.
Design of 3 Step Motor and Driver Products
As mentioned above, stepping motors are widely used, such as in ATM automatic teller machine for money control and passbook involvement functions, as in vending machines for goods movement, as well as in *** for wheel rotation and so on. This paper focuses on stepping motors and drivers for office automation applications. Typical products are printers and scanners. Usually, the functions of paper feeding, paper tray and scanning may be used in stepping motor for position control.
The stepper motor moves the paper from point A to point B accurately. If the primary requirement of end users is silent drive, then it is suitable to use low vibration micro step motor. In such applications, stepping motors and DC brushless motors are used to press ink tape onto paper. Stepping motors are required to regulate the pressure of ink tape on paper where it needs to be positioned. In desktop scanner and other equipment, the designer chooses the motor with positioning function, low vibration and motor rotation control range.
Characteristic, Advantage and Application Example of 4 LV8702 High Energy Efficiency Stepping Motor Driver
At present, the energy efficiency of stepping motors used in various electronic products is low, which has become a focus of attention in the industry, and also brings challenges to power system design engineers. The LV8702 high energy efficiency stepper motor drive IC introduced by Ansenmei Semiconductor overcomes these challenges, provides unique driving system, helps save no-load energy consumption of the motor, and provides multiple application advantages.