Four-quadrant inverter technology introduction
Qingdao Hanneng Electric Co., Ltd.
basic concept:
1. Four quadrants: The plane is divided into four parts by two orthogonal axes, which are four quadrants;
2. The two numerical axes respectively give different meanings or represent parameters with different meanings. In this case, the four quadrants represent the four states of motion or change of the object when the parameters change.
3. The state of motion or change can be described by two independent parameters with opposite meanings. The state can be described by four quadrants. If three parameters are not four quadrants, but eight quadrants;
Therefore, according to the different definitions of several axes, the four-quadrant operation of the inverter can be divided into the following situations:
1. For example, describe the running status of the motor with four quadrants: first determine two parameters, one is the rotor's electromagnetic torque m with the Y axis, one is the running direction n with the X axis, then the four quadrants describe the four motors The operating states are as follows: 1 quadrant is forward rotating; 2 quadrants are reverse braking power generation; 3 quadrants are reversed motorized; 4 quadrants are forward braking power;
2. For example, use four quadrants to describe the operation status of the rectifier: first determine two parameters, one is the direction of change with the Y axis, one is the polarity of the DC voltage with the X axis, then the four quadrants describe the four operating states of the rectifier Respectively: 1 quadrant is in positive polarity rectification state; 2 quadrants are in reverse polarity rectification state; 3 quadrants are in reverse polarity inversion state; 4 quadrants are in positive polarity inversion state;
3. For example, use 4 quadrants to describe the operating status of the inverter: first determine the two parameters, then you find that there is a problem, what is the operating status of the inverter, invert direction? Or the four states of the motor? The four states of the rectifier? The four states of the inverter? So the definition is different, and the meaning of the four quadrants is different. If you combine the state of the motor, determine two parameters, one for the direction of change with the Y axis and one for the direction of rotation of the motor with the X axis, then the four quadrants of the drive are described as: 1 quadrant is the forward rotation state; 2 quadrants To reverse the electric state; 3 quadrants are the reverse power generation feedback state; 4 quadrants are the forward relay feedback state;
4. When the meaning of the two coordinate axes is different, the state meaning of the four-quadrant description is different.
Four-quadrant inverter working principle:
1 When the motor is in the dragging state, the energy is charged by the AC grid through the filter capacitor in the rectifier, and the inverter reduces the energy in the PWM control to the motor;
2 When the motor is in a deceleration mode, the inertia of the load enters into the power generation state. The regenerative energy of the motor is charged to the intermediate filter capacitor via the switching element and freewheeling diode in the inverter, so that the intermediate DC voltage is increased, and the switching element in the rectifier is now The PWM control reduces the energy feed to the AC grid, completing the bidirectional flow of energy. At the same time, due to the closed-loop control of the PWM rectifier, the grid current and voltage have the same frequency and phase, which improves the power factor of the system and eliminates the side harmonic pollution.
Dual PWM control technology breaks down the unified structure of the inverter in the past, uses PWM rectifier and PWM inverter to improve the system power factor, and realizes the four-quadrant operation of the motor, which adds a new vitality to the inverter technology and forms a high The latest development of quality energy feedback technology.
Qingdao Shengneng Electric Co., Ltd. currently has 380V4Q (75KW ~ 500KW), 660V4Q (75KW ~ 500KW), 1140V4Q (power: 75KW ~ 500KW) series four-quadrant inverter. Telephone Wu Jingli
Welcome to negotiate phones work!