Three-level double-current hysteresis loop power amplifier

Abstract

The invention discloses a three-PWL double-current hysteresis power amplifier which comprises an error comparing module, a PI current controller module, a double-current hysteresis comparing module, an optical coupler isolation driving module, a power changing module and a current feedback current. The traditional current hysteresis control and the three-PWL modulation are combined, thus, the advantages of simple structure, good current tracking performance and low cost of the hysteresis control circuit and the advantages of small current ripples, high control accuracy and low output harmonic wave content are obtained. The power amplifier can be used for all occasions with the requirements of controlling the output current, i.e. the power amplifying part of an active electromagnetic bearing or a vibration generator, and the like.

Description

technical field [0001] The invention relates to a power amplifier, in particular to a three-level double current hysteresis power amplifier. Background technique [0002] With the development of power electronics technology, switching power amplifiers have been widely used due to their high efficiency and ability to withstand large currents and high voltages. For example, in the field of active electromagnetic bearings, high-efficiency switching power amplifiers are generally used to replace linear power amplifiers. Regardless of the linear power amplifier or the switching power amplifier, the power amplifier can be divided into a current-controlled power amplifier and a voltage-controlled power amplifier according to the control type. The electric current of the electromagnetic coil is called the current control type, and the voltage of the electromagnetic coil is called the voltage control type. For example, in the electromagnetic bearing system, since the output of the ...

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Problems solved by technology

The characteristic of the triangular wave carrier comparison method is that the frequency is fixed, but there is a relatively obvious phase difference between the output voltage and the output current.

For example, the three-level modulation method of the improved sample-and-hold strategy, the control circuit is complex, and only various discrete digital-analog device combinations can be used. Modular products are rarely used, and the reliability is low.

The three-level switching power structure using phase-shift SPWM technology is too complicated, and it is obviously not suitable for small and medium-sized active electromagnetic bearings

In addition, although the switching power amplifier using all-digital technology can achieve relatively good performance, the hardware cost is too high, and high-speed digital-to-analog converters and digital controllers are required. For small and medium-sized power amplifiers, their prices account for most of the power amplifier. cost

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