When using daily industrial control, the key factors of energy feedback device selection:
Load Characteristics Match
Constant torque loads (e.g. cranes, hoists) require the selection of feedback devices with high dynamic responsiveness to ensure rapid absorption of renewable energy.
Variable torque loads (e.g. fans, water pumps) need to adjust the feedback power threshold according to the speed-torque curve (e.g. square torque characteristics).
Power and voltage rating
The rated power of the feedback device should be ≥ 1.1 times the rated power of the motor, and the motherboard voltage should match the grid voltage (such as 400V / 660V systems).
High-power devices (>100kW) recommend four-quadrant frequency converters to support bidirectional energy flow.
Grid Compatibility
The grid voltage fluctuation range (±20%) needs to be detected to ensure that the feedback current harmonic distortion rate (THD) < 5%.
Choose devices with voltage/frequency synchronous detection to avoid feedback current and grid failure.
Technical classification and application scenarios
Type Feature Scenario
Separate installation, easy to maintain, but requires additional wiring
All-in-one integrated in frequency converter, fast response, high cost New industrial equipment (such as centrifuge)
Energy storage with battery pack, suitable for off-grid or unstable scenarios without grid feedback
Economics and Energy Efficiency Assessment
Energy saving rate: the elevator energy feedback device can be up to 17.85% -40.37%, it is necessary to calculate the investment return period in combination with the load rate.
Cost comparison: The price of the feedback device is about 2-3 times the energy consumption of the brake, but the long-term energy saving benefits are significant.
Installation and Maintenance
Cooling design
High-power feedback device requires forced air cooling (such as explosion-proof fan) to ensure IGBT bonding temperature < 125 ℃.
≥100mm heat dissipation space is reserved inside the case to avoid heat accumulation.
Protection function
Overvoltage, overcurrent, overheating and grid backlash protection are required, such as automatic cutting when the motherboard voltage exceeds 1.2 times the effective value of the grid.
Selection process recommendations
Measuring the load curve: Determine the peak of renewable energy through the torque-speed test.
Grid detection: Verify the harmonic content and voltage stability of the grid.
Simulation Validation: Using tools such as MATLAB to simulate feedback current waveforms to optimize control parameters.