A High Efficiency Low Ripple Frequency Conversion Modulation Method

Abstract

The invention discloses a high-efficiency and low-ripple frequency conversion modulation method, which belongs to the technical field of electric power transmission; the invention drives an inverter composed of two high-frequency switching devices and six low-frequency switching devices, and improves the zero-frequency modulation method in the traditional space vector modulation strategy. The generation method and timing of the vector, the high-frequency device controls the bus voltage to be zero instead of the zero-voltage vector, and provides zero-voltage switching conditions for the low-frequency device; the low-frequency device only generates an effective voltage vector, and the number of switching actions is reduced. The switching loss characteristic reduces the inverter loss, thereby increasing the available switching frequency of the inverter and reducing the current ripple; the invention adjusts the carrier period in real time according to the predicted value and the given value of the current ripple, reduces the current ripple, and improves the system performance. Electromagnetic compatibility performance; the modulation algorithm proposed by the present invention can achieve higher system working efficiency, lower current ripple output, and higher current control accuracy at the same time, and has certain application value.

Description

A High Efficiency Low Ripple Frequency Conversion Modulation Method technical field [0001] The present invention relates to the technical field of electric drive, in particular to a high-efficiency low-ripple frequency conversion modulation method. Background technique In the working process of the inverter, due to the nonlinearity of the switching device, as well as the high fundamental frequency or high power work field [0002] The switching frequency of the power device is relatively low, and the low carrier frequency ratio increases the output current ripple of the inverter, and the harmonic components Increase, and mostly focus on multiples of switching frequency, drive control of motor, safe operation of public power grid and electromagnetic system of the system. Compatibility comes with a lot of downsides: 1. cause motor torque pulsation, increase the running noise of motor, bearing damage and overall loss, accelerate temperature rise, shrink The service life...

AI Technical Summary

Problems solved by technology

[0002] During the working process of the inverter, due to the non-linearity of the switching device and the limitation of high fundamental frequency or high-power workplace, the switching frequency of the power device is relatively low, and the low carrier frequency ratio increases the output current ripple of the inverter. , the harmonic components increase, and most of them are concentrated in multiples of the switching frequency, which has many adverse effects on the drive control of the motor, the safe operation of the public power grid, and the electromagnetic compatibility of the system:

[0003] 1. Cause motor torque pulsation, increase motor operating noise, bearing damage and overall loss, accelerate temperature rise, shorten the service life of the motor, and in severe cases, the loss of the stator and rotor of the motor is too large, the motor heats up seriously, and causes irreversible damage to the motor

[0004] 2. Affect the stability of the power grid, output lines, and normal operation of electrical equipment, transformers, metering and communication equipment

Inject harmonics into the grid, consume active and reactive power, easily cause relay protection devices to malfunction, and affect the life of electrical equipment and the stability of grid output lines

[0005] 3. Generate electromagnetic interference, affect the normal operation of the drive control circuit, and reduce the system operation stability, safety reliability and electromagnetic compatibility

Images