High-efficiency low-ripple frequency conversion modulation method

Abstract

The invention discloses a high-efficiency low-ripple frequency conversion modulation method, and belongs to the technical field of power transmission. An inverter composed of two high-frequency switching devices and six low-frequency switching devices is driven, the generation mode and time sequence of a zero vector in a traditional space vector modulation strategy are improved, the high-frequencyswitching devices control bus voltage to be zero to replace the zero voltage vector, meanwhile zero voltage switching conditions are provided for the low-frequency switching devices, the low-frequency switching device only generates an effective voltage vector, the switching action frequency is reduced, and the loss of the inverter is reduced by utilizing the low switching loss characteristic ofthe high-frequency switching device, so that the available switching frequency of the inverter is improved, the current ripple is reduced, the carrier period is adjusted in real time according to thepredicted value and the given value of the current ripple, the current ripple is reduced, and the electromagnetic compatibility of the system is improved, according to the modulation algorithm provided by the invention, higher system working efficiency, lower current ripple output and higher current control precision can be obtained at the same time, and the modulation algorithm has a certain application value.

Description

technical field [0001] The invention relates to the field of electric drive technology, in particular to a high-efficiency and low-ripple frequency conversion modulation method. Background technique [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 torque pulsation of the motor, increase the operating noise of the motor, damage the bearing and overall loss, accelerate the temperature rise, shorten the service life ...

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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

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