Delta Electronics, Inc.

Delta Electronics (shanghai) Co., Ltd

Ai-Bin Qiu

Jian-Ping Ying

Jian-Hong Zeng

Fei Lu

Chang-Yong Wang

Zi-Ying Zhou

Hai-Fen Xue

Jian-Fei Zheng

Ming-Xuan Dong

Yan Ma

A method for estimating capacitance applied to a three phase converting device is disclosed. The three phase converting device includes a three phase converter and a processor. The processor executes following steps: (a) outputting a non-baseband signal to the three phase converter, such that a bus voltage of the three phase converter generates a non-baseband flutter; (b) obtaining the bus voltage of the three phase converter; (c) obtaining a bus voltage estimating value based on the bus voltage, a bus capacitance estimating value, an input power, and an output power of the three phase converter; (d) respectively outputting a first AC component and a second AC component corresponding to the non-baseband flutter through filtering the bus voltage and the bus voltage estimating value by a filter segment; (e) estimating a bus capacitance based on the first AC component, the second AC component and a bus capacitance initial value.

Three phase converting device and method for estimating capacitance

A phase locking system for a three-phase alternating current (AC) electric grid and a method thereof are disclosed. The method includes: receiving a three-phase voltage of the AC electric grid and converting the three-phase voltage to a two-phase voltage signal, each of which including a positive and a negative sequence components; obtaining a pure positive sequence component by subtracting the negative sequence component from the voltage signal of each phase and using &#x3b1;&#x3b2;/dq coordinate transformation and low-pass filtering, and phase locking the pure positive sequence component; and obtaining an error signal by subtracting a disturbance variable and subsequently subtracting the positive sequence component from the voltage signal of each phase, wherein the disturbance variable includes the negative sequence component, and obtaining a signal including the negative sequence component by performing a &#x3b1;-&#x3b2;/d-q coordinate transformation on the error signal and adjusting the error signal through a regulator.

Phase locking system for three-phase alternating current electric grid and method thereof

A sampling method with adjusting duty ratios is provided and includes the following steps. A first working pulse signal which has a pulse-width duty ratio D in a switching period Tis provided. A first adjusting period comprising first N successive switching periods of the first working pulse signal is set, wherein N is a natural number larger than 1. A second working pulse signal which has second N successive switching periods with their corresponding pulse-width duty ratio D, D, . . . , Dto drive the switch in the converter circuit is provided and the measured signal is generated, wherein the sum of D, D, . . . , Dsubstantially equals to N&#xb7;D and the second N successive switching periods constitute a second adjusting period.

Sampling method with adjusting duty ratios

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Shanghai, China

Ai-Bin Qiu