The supplier of frequency converter supporting equipment reminds you that in industrial production, considering the particularity of working conditions, if a certain fault occurs in the system, causing the potential energy load carried by the motor to accelerate freely and fall, the motor will be in a power generation operation state. The regenerated energy will be sent back to the DC circuit through six freewheeling diodes, causing an increase in ∆ d and quickly putting the frequency converter in a charging state. At this time, the current will be very high. So the selected reactor wire diameter should be large enough to pass the current at this time.
The Dynamic Braking Unit is mainly used in situations where the frequency converter requires rapid deceleration, positioning, and braking. When the frequency converter is braking, due to the large inertia of the load, it will convert kinetic energy into electrical energy, causing the DC bus voltage of the frequency converter to rise. In order not to affect the normal operation of the frequency converter, it is necessary to use a braking unit to consume the regenerated electrical energy, otherwise the frequency converter will skip the voltage protection and affect its normal operation.
The function of the energy feedback device is to effectively return the regenerated electric energy of the motor to the AC power grid for use by other surrounding electrical equipment. The energy-saving effect is very obvious, and the general energy-saving rate can reach 20% to 50%. In addition, due to the absence of resistance heating elements, the temperature in the computer room drops, which can save the power consumption of the computer room air conditioning. In many cases, saving air conditioning power consumption often leads to better energy-saving effects.
To operate the variable frequency speed regulation system in an energy feedback state, the following conditions must be met:
(1) The grid side requires the use of controllable inverters. When the motor operates in the energy feedback state, in order to achieve energy feedback to the grid, the grid side inverter must operate in the inversion state, and uncontrollable inverters cannot achieve inversion.
(2) The DC bus voltage should be higher than the feedback threshold. The frequency converter needs to feedback energy to the grid, and the DC bus voltage value must be higher than the feedback threshold in order to output current to the grid. As for the threshold setting, it depends on the grid voltage and the voltage resistance performance of the frequency converter.
(3) The feedback voltage frequency must be the same as the grid voltage frequency. During the feedback process, it is necessary to strictly control the output voltage frequency to be the same as the grid voltage frequency to avoid surge impact.
Transforming the mechanical energy (potential energy, kinetic energy) on the load during motion into electrical energy (regenerated electrical energy) through an energy feedback device and returning it to the AC power grid for use by other nearby electrical equipment, so that the motor drive system can reduce the consumption of grid electrical energy per unit time, thereby achieving the goal of energy conservation.