Sensorless measurement method and device for filter capacitor current by using a state observer

Patent metadata

Field	Value
Publication number	US-10103647-B2
Application number	US-201615354528-A
Country	US
Kind code	B2
Filing date	Nov 17, 2016
Priority date	Aug 17, 2016
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

Abstract

A sensorless measurement device for filter capacitor current by using a state observer is provided. The sensorless measurement device comprises a chip, wherein the chip comprises the state observer. The state observer is configured to retrieve a filter-capacitor-voltage actual value and a direct current link (dc-link) voltage of a present sampling time. According to the filter-capacitor-voltage actual value and the dc-link voltage, the state observer is configured to output a filter-capacitor-voltage state variable value, a filter-capacitor-current state variable value, and a disturbance-voltage state variable value of a next sampling time. The filter-capacitor-current state variable value is an average current value without ripples.

First claim

What is claimed is:

1. A sensorless measurement method for filter-capacitor-current by using a state observer, comprising:
receiving a filter-capacitor-voltage actual value of a present sampling time;
receiving a direct current link (dc-link) voltage of the present sampling time;
outputting, by the state observer, a filter-capacitor-voltage state variable value, according to the filter-capacitor-voltage actual value and the dc-link voltage, wherein the filter-capacitor-voltage state variable value is a predicted voltage value of a next sampling time; and
outputting, by the state observer, a filter-capacitor-current state variable value, wherein the filter-capacitor-current state variable value is a predicted current value of the next sampling time, and the filter-capacitor-current state variable value is an average current value without ripples.

2. The sensorless measurement method of claim 1 , comprising:
outputting, by the state observer, a disturbance-voltage state variable value, wherein the disturbance-voltage state variable value is a predicted voltage value of the next sampling time.

3. The sensorless measurement method of claim 1 , comprising:
receiving a load-current actual value of the present sampling time; and
outputting, by the state observer, a load-current state variable value, according to the load-current actual value, wherein the load-current state variable value is a predicted current value of the next sampling time.

4. A sensorless measurement method for filter capacitor current by using a state observer, comprising:
detecting a filter-capacitor-voltage actual value and a direct current link (dc-link) voltage of a present sampling time;
calculating, by the state observer, a filter-capacitor-voltage state variable value, a filter-capacitor-current state variable value, and a disturbance-voltage state variable value of a next sampling time;
comparing a filter-capacitor-voltage command value with the filter-capacitor-voltage state variable value, and obtaining a filter-capacitor-current command value;
comparing the filter-capacitor-current command value with the filter-capacitor-current state variable value, and obtaining a voltage control value;
comparing the voltage control value with a feed-forward-voltage state variable value, and obtaining a pulse-width-modulation comparison value, wherein the feed-forward-voltage state variable value equals the disturbance-voltage state variable value divided by the dc-link voltage; and
proceeding a switch control of pulse-width-modulation according to the pulse-width-modulation comparison value.

5. The sensorless measurement method of claim 4 , comprising:
detecting a load-current actual value of the present sampling time;
calculating, by the state observer, a load-current state variable value of a next sampling time; and
comparing a load-current command value with the load-current state variable value, and obtaining the filter-capacitor-voltage command value.

6. A sensorless measurement device for filter capacitor current by using a state observer, comprising:
a chip comprising the state observer, wherein the state observer is configured to retrieve a filter-capacitor-voltage actual value and a direct current link (dc-link) voltage of a present sampling time, according to the filter-capacitor-voltage actual value and the dc-link voltage; and configured to output a filter-capacitor-voltage state variable value, a filter-capacitor-current state variable value, and a disturbance-voltage state variable value of a next sampling time, wherein the filter-capacitor-current state variable value is an average current value without ripples.

7. The sensorless measurement device of claim 6 , wherein the state observer is configured to obtain a load-current actual value of the present sampling time, according to the load-current actual value, and configured to output a load-current state variable value of the next sampling time.

8. The sensorless measurement device of claim 7 , wherein the state observer comprises a formula of calculating the load-current state variable value as follows:

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Assignees

• Ind Tech Res Inst

Inventors

• Huang Shu-Syuan
• Konishi Yoshihiro
• Yang zong-zhen
• Hsieh Min-Ju

Classifications

• H02M1/14

  Arrangements for reducing ripples from DC input or output · CPC title

• G01R19/003

  Measuring mean values of current or voltage during a given time interval · CPC title

• H02M2001/0009

  Electricity · mapped topic

• G01R19/2509

  Details concerning sampling, digitizing or waveform capturing · CPC title

• H02M7/53871 Primary

  with automatic control of output voltage or current · CPC title