Inverter and uninterruptible power supply

Abstract

The invention discloses an inverter and an uninterruptible power supply and relates to the technical field of power electronics. Filtering inductive current can be detected with a lower cost, and the problems of delaying and incapability of detecting a direct current component are avoided. The inverter comprises a chopper circuit, a control circuit and a filtering inductance. The control circuit is connected with the chopper circuit, the filtering inductance is connected with the chopper circuit, the filtering inductance comprises n guide lines (n> / =2), the n guide lines have the same length and are wound on the same magnetic core, and the n guide lines have the same cross section area and include p first guide lines (n>p> / =1), and the inverter further comprises a Hall sensor, a low pass filter, a current transformer and a computing element. The Hall sensor is used for detecting total current on the P first guide lines, the low pass filter is connected onto the Hall sensor, the current transformer is used for detecting the total current on the n guide lines and outputting a third measured value, and the computing element is used for acquiring a fourth measured value reflecting magnitude of the direct current component of the total current on the n guide lines according to an output signal of the Hall sensor.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to an inverter and an uninterruptible power supply. Background technique [0002] An inverter is a device that converts direct current into alternating current and is widely used. Up to now, there are many circuit topologies for inverters. Taking voltage-type inverters as an example, they can be half-bridge inverters, full-bridge inverters, and multi-level inverters. Such as figure 1 As shown, no matter which topology, the inverter mainly includes 5 parts: DC source 1, chopper circuit 2, LC filter circuit, detection circuit 4 and control circuit 3. Among them, the current of the filter inductor L needs to be detected, one is to enable the control circuit to perform loop control according to the measurement signal to stabilize the output, and the other is to limit the current wave by wave to prevent damage to the switching tube in the chopper circuit. [0003] In the pri...

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Problems solved by technology

If HCT is used to detect the filter inductor current, the price of HCT with the same capacity is much higher than that of CT, which increases the cost, and the output signal of HCT has a delay of several microseconds relative to the actual current signal, thus increasing The delay of the loop control is reduced and the actual current limit point is higher than the theoretical current limit point during the wave-by-wave current limit, which increases the current stress during the wave-by-wave current limit

If a CT is used to detect the filter inductor current, if the load of the inverter is a half-wave load or when multiple inverters are paralleled, the filter inductor current will include a DC component, which cannot be detected due to the characteristics of the CT itself. DC component, so precise control is not possible

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