Three-phase converter and capacitance estimation method

Abstract

A capacitance estimation method is applied to a three-phase converter. The three-phase converter comprises a three-phase converter and a processor. The processer is employed to execute the following steps of: (a) outputting non-fundamental signals to a three-phase converter to allow a bus voltage of the three-phase converter to generate non-fundamental fluctuation; (b) obtaining the bus voltage ofthe three-phase converter; (c) according to the bus voltage, a bus capacitance estimation value, an input power and an output power of the three-phase converter, obtaining a bus voltage estimation value; (d) allowing the bus voltage and the bus voltage estimation value to be subjected to a filtering link to output a first alternating current component and a second alternating current component corresponding to the non-fundamental fluctuation; and (e) according to the first alternating current component, the second alternating current component and a bus capacitance initial value, estimating abus capacitance value.

Description

technical field [0001] The invention relates to a converter device and a method for estimating parameters of internal components of the converter device, and in particular to a three-phase converter device and a method for estimating capacitance of the three-phase converter device. Background technique [0002] In three-phase systems (such as converters, frequency converters, etc.), the size of the DC bus capacitor has a certain impact on the stable operation of the system. It is necessary to quickly and accurately detect the value of the DC bus capacitor online, so as to determine the life of the capacitor. Make reasonable assessments, issue warnings when necessary, and perform maintenance in a timely manner to protect the stable operation of the system. [0003] At present, there are several ways to detect the value of the DC bus capacitance of the three-phase system. For example, an independent detection device can be used to directly connect the two ends of the capacitor...

AI Technical Summary

Problems solved by technology

However, if the above method is used for detection, external equipment is required, and the cost is high

[0004] In addition, if the detection is based on the three-phase converter itself, generally speaking, the detection method will be combined with the product application, which is not conducive to popularization and application. For example, an elevator company will estimate the DC side capacitance and the position information of the elevator car combine together

Furthermore, detection based on the three-phase converter itself, such as estimating the capacitance value during the pre-charging process of the DC bus of the three-phase converter, may lead to the following disadvantages: 1. The detection of the capacitance value can only It is detected once when charging, and the change of capacitance value cannot be detected during stable operation; 2. The energy carried by the capacitor may be estimated inaccurately through power estimation, which affects the accuracy of capacitance value estimation

In addition, the detection is also based on the three-phase converter itself, and the ripple voltage of the bus voltage is collected during the operation of the three-phase converter, and the capacitance value is directly estimated according to the capacitance characteristics, which may lead to the following disadvantages: high-frequency ripple Difficult to detect accurately, affecting the accuracy of capacitance estimation

[0005] This shows that above-mentioned existing mode obviously still has inconvenience and defective, and needs to be improved

In order to solve the above problems, related fields have tried their best to find a solution, but a suitable solution has not been developed for a long time.

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