What is the difference between a servo drive and a servo motor?

Servo drive definition:
　　Servo drives, also known as "servo controllers" and "servo amplifiers", are a kind of controller used to control servo motors, which act like inverters on ordinary AC motors and are part of servo systems and are mainly used in high-precision positioning systems. Generally through the position, speed and torque of the three ways of servo motor control, to achieve high-precision transmission system positioning, is currently a high-end transmission technology products.
　　Servo motor definition:
　　A servo motor is an engine that controls the operation of mechanical components in a servo system and is an indirect variable speed device for a subsidized motor. Servo motors enable control speed and position accuracy to be so accurate that voltage signals can be converted into torques and speeds to drive control objects. Servo motor rovel is controlled by the input signal and can react quickly, in the automatic control system, as an executive element, and has the characteristics of small mechanical and electrical time constant, high linearity, can be received electrical signals into the motor shaft angle displacement or ad angle speed output. It is divided into dc and AC servo motors, the main features of which are that when the signal voltage is zero, there is no turning phenomenon, and the speed decreases at a constant speed with the increase of torque.
　　How servo drives work:
　　At present, the mainstream servo drives use digital signal processor (DSP) as the control core, which can realize the more complex control algorithm, realize the digitalization, networking and intelligence. Power devices generally use intelligent power module (IPM) as the core design of the drive circuit, IPM integrated drive circuit, at the same time has overvoltage, overcurrent, overheating, undervoltage and other fault detection and protection circuit, in the main circuit also added a soft start circuit to reduce the impact of the start-up process on the driver. The power drive unit first rectives the input three-phase electricity or mains electricity through the three-phase full-bridge rective circuit, and obtains the corresponding DC power. After the rectifier of good three-phase electricity or mains, and then through the three-phase sine PWM voltage inverter inverter frequency to drive three-phase permanent magnetic synchronous AC servo motor. The whole process of the power drive unit can simply be said to be the AC-DC-AC process. The main topological circuit of the rectry unit (AC-DC) is the three-phase full-bridge unsystote circuit.
　　How servo motors work:
　　1. Servo mechanism is an automatic control system that enables the output of an object's position, position, status, etc. to follow any change in the input target (or given value). Servo mainly rely on pulses to locate, basically it can be understood that the servo motor receives 1 pulse, will rotate 1 pulse corresponding angle, so as to achieve displacement, because the servo motor itself has the function of issuing pulses, so the servo motor every rotation of an angle, will emit a corresponding number of pulses, so, and The pulses received by the servo motor form an echo, or closed loop, so that the system will know how many pulses are sent to the servo motor, and at the same time how many pulses are received back, so that the rotation of the motor can be very precisely controlled, so as to achieve accurate positioning, can reach 0.001mm. DC servo motors are divided into brushed and brushless motors. Brush motor cost is low, simple structure, large start-up torque, wide speed range, easy control, maintenance is required, but maintenance is not convenient (carbon brush), electromagnetic interference, environmental requirements. It can therefore be used in cost-sensitive general industrial and civil applications. Brushless motor small size, light weight, large force, fast response, high speed, small inertia, smooth rotation, stable torque. The control is complex, easy to realize the intelligence, its electronic exchange mode is flexible, can square wave exchange or sine wave exchange. Motor maintenance-free, high efficiency, low operating temperature, electromagnetic radiation is very small, long life, can be used in a variety of environments.
　　2, AC servo motor is also brushless motor, divided into synchronous and asynchronous motor, motion control is generally used synchronous motor, its power range is large, can do a lot of power. Large inertia, low maximum rotation speed, and rapid decrease as power increases. It is therefore suitable for applications that run smoothly at low speeds.
　　3, the rotor inside the servo motor is a permanent magnet, the driver-controlled U/V/W three-phase electric formation electromagnetic field, the rotor in the role of this magnetic field rotation, while the motor's own encoder feedback signal to the driver, the driver according to the feedback value and the target value comparison, adjust the angle of rotor rotation. The accuracy of the servo motor depends on the accuracy of the encoder (number of lines). The functional difference between an AC servo motor and a brushless DC servo motor: AC servo is better because it is sine wave control and the torque pulsation is small. A DC servo is a trapezoidal wave. But DC servo is simpler and cheaper.