Unlock instant, AI-driven research and patent intelligence for your innovation.

Single-resistor current sampling method and device

A current sampling, single-resistor technology, used in measuring devices, measuring current/voltage, measuring electrical variables, etc., can solve the problems of sampling current and current signal accuracy reduction, and achieve the effect of ensuring sampling accuracy

Pending Publication Date: 2021-11-23
SHANGHAI STEP ELECTRIC
View PDF0 Cites 1 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, since the single-resistance current sampling method cannot sample the current at the voltage zero vector, the current collected by the general single-resistance current sampling method contains current ripple signals, thereby reducing the accuracy of the sampled current signal.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Single-resistor current sampling method and device
  • Single-resistor current sampling method and device
  • Single-resistor current sampling method and device

Examples

Experimental program
Comparison scheme
Effect test

no. 1 example

[0045] In this embodiment, the three-phase duty ratio calculated by the PWM control algorithm is firstly adjusted, then the time of two samplings is calculated, and finally the three-phase current is reconstructed according to the bus current obtained by sampling. The single-resistor current sampling method in this embodiment is applied to a frequency converter, the carrier period of the frequency converter is T, and the minimum sampling window is T s , the PWM control algorithm and the sampling algorithm are executed once per carrier period, and the PWM control algorithm is used to control the operation of the motor. The concrete steps of this first embodiment are as follows:

[0046] Step a. Adjust the three-phase duty ratios D[a], D[b], and D[c] calculated by the PWM control algorithm to obtain the adjusted three-phase duty ratio D 1 [a], D 1 [b], D 1 [c], and D 2 [a], D 2 [b], D 2 [c]; Step a further includes:

[0047] a1. First, sort the three-phase duty ratios D[a...

no. 2 example

[0075] In this embodiment, the three-phase duty ratio calculated by the PWM control algorithm is firstly adjusted, and then the four sampling times are calculated, and finally the three-phase current is reconstructed according to the bus current obtained by sampling. The single-resistor current sampling method in this embodiment is applied to a frequency converter, the carrier period of the frequency converter is T, and the minimum sampling window is T s, the PWM control algorithm and the sampling algorithm are executed every two carrier cycles, that is, the sampling algorithm cycle is equal to two carrier cycles, and the PWM control algorithm is used to control the operation of the motor. The concrete steps of this second embodiment are as follows:

[0076] Step a. Adjust the three-phase duty ratios D[a], D[b], and D[c] calculated by the PWM control algorithm to obtain the adjusted three-phase duty ratio D 1 [a], D 1 [b], D 1 [c], and D 2 [a], D 2 [b], D 2 [c]; Step a f...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a single-resistor current sampling method and device. The method comprises the following steps of: a, adjusting a three-phase duty ratio calculated by a motor control algorithm to obtain an adjusted three-phase duty ratio; b, calculating a current sampling moment according to the adjusted three-phase duty ratio; c, outputting a three-phase voltage according to the adjusted three-phase duty ratio; and d, performing current sampling at the current sampling time, and reconstructing a three-phase current according to a current sampling result. According to the invention, single-resistor current sampling can be realized, and the sampling precision is ensured.

Description

technical field [0001] The invention relates to single-resistance current sampling technology. Background technique [0002] The frequency converter is generally a three-phase output and is used to control a three-phase AC motor. Inverters generally require three-phase current signals to realize motor control, and at the same time, protection of the inverter and the motor must also be realized based on the three-phase current signals. There are many ways to obtain the three-phase current signal. Obtaining the current signal through the sampling resistor is a common current sampling method. According to the number of sampling resistors, current sampling methods can be divided into three-resistor current sampling, two-resistor current sampling and single-resistor current sampling, among which the hardware cost of single-resistance current sampling is the lowest. When the system cost is high, single-resistor current sampling is a better choice. [0003] The single-resistor c...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): G01R19/00
CPCG01R19/00
Inventor 李柏松陈伟时迎亮成爱军李武君
Owner SHANGHAI STEP ELECTRIC