Voltage sensorless control of power converters

• US 6,297,621 B1
• Filed: 03/13/2000
• Issued: 10/02/2001
• Est. Priority Date: 03/13/2000
• Status: Expired due to Term

• Current Assignee: City University of Hong Kong
• Original Assignee: City University of Hong Kong
• Inventors: Hui, Ron Shu-Yuen, Chung, Henry Shu-Hung
• Primary Examiner(s): Riley, Shawn
• Application Number:
  US09/524,041
• Time in Patent Office: 568 Days
• Field of Search: 323/283, 323/285, 323/286, 323/290, 323/222
• US Class Current: 323/222
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

Apparatus and methods are described for the voltage control of power converters in which the input and output voltages of the converter are not sensed directly but are derived from an inductor voltage which in turn is derived by sensing an instantaneous inductor current.

Claims

1. Apparatus for the voltage control of power converter, comprising means for sensing an inductor current and means for deriving input and/or output voltages from said current, wherein said apparatus further comprises means for converting said inductor current to an inductor voltage comprising:

(a) means for continuously determining an instantaneous inductance,

(b) means for continuously determining a rate of change of said inductor current,

(c) means for multiplying said inductor current by an inductor resistance,

(d) means for generating a product of the outputs of (a) and (b), and

(e) means for summing the outputs of (c) and (d).

2. Apparatus as claimed in claim 1 wherein the output of said inductor current to inductor voltage converting means comprises positive and negative envelopes and wherein said input and output voltage deriving means comprises means for demodulating said envelopes.

3. Apparatus as claimed in claim 1 wherein said derived input and/or output voltage is input to a control circuit.

4. Apparatus as claimed in claim 2 wherein said converter is a buck converter and means are provided to reverse the sign of the demodulated negative envelope to derive the output voltage, and wherein means are provided to subtract the demodulated negative envelope from demodulated positive envelope to derive the input voltage.

5. Apparatus as claimed in claim 2 wherein said converter is a boost converter and means are provided to subtract the demodulated negative envelope from the demodulated positive envelope to derive the output voltage, and wherein the input voltage is derived directly from the demodulated positive envelope.

6. Apparatus as claimed in claim 2 wherein said converter is a buck boost converter and wherein means are provided to reverse the sign of the demodulated negative envelope to derive the output voltage, and wherein the input voltage is derived directly from the demodulated positive envelope.

7. Apparatus as claimed in claim 2 wherein said converter is a flyback converter and wherein means are provided to reverse the sign of the demodulated negative envelope to derive the output voltage, and wherein the input voltage is derived directly from the demodulated positive envelope.

8. Apparatus as claimed in claim 2 wherein said converter is a forward converter and wherein means are provided to reverse the sign of the demodulated negative envelope to derive the output voltage, and wherein the demodulated negative envelope is subtracted from the demodulated positive envelope to determine a product of the input voltage and a transformer ratio.

9. A method for the voltage control of a power converter comprising sensing an inductor current and deriving input and output voltages from said current, wherein said method further comprises converting said inductor current to an inductor voltage comprising:

(a) continuously determining an instantaneous inductance,

(b) continuously determining a rate of change of said inductor current,

(c) multiplying said inductor current by an inductor resistance,

(d) generating a product of the outputs of (a) and (b), and

(e) summing the outputs of (c) and (d).

10. A method as claimed in claim 9 wherein said inductor voltage comprises positive and negative envelopes and wherein said input and said output voltages are derived by demodulating said envelopes.

11. A method as claimed in claim 9 wherein said derived input and/or output voltage is used as an input to a control circuit.

12. A method as claimed in claim 10 wherein said converter is a buck converter and wherein the output voltage is derived by reversing the sign of the demodulated negative envelope, and wherein the input voltage is derived by subtracting the demodulated negative envelope from the demodulated positive envelope.

13. A method as claimed in claim 10 wherein said converter is a boost converter and wherein the output voltage is derived by subtracting the demodulated negative envelope from the demodulated positive envelope, and wherein the input voltage is derived directly from the demodulated positive envelope.

14. A method as claimed in claim 10 wherein said converter is a buck boost converter, wherein the output voltage is derived by reversing the sign of the demodulated negative envelope, and wherein the input voltage is derived directly from the demodulated negative envelope.

15. A method as claimed in claim 10 wherein said converter is a flyback converter, wherein the output voltage is derived by reversing the sign of the demodulated negative envelope, and wherein the input voltage is derived directly from the demodulated negative envelope.

16. A method as claimed in claim 10 wherein said converter is a forward converter, wherein the output voltage is derived by reversing the sign of the demodulated negative envelope, and wherein the product of the input voltage and the transformer turn ratio is derived by subtracting the demodulated negative envelope from the demodulated positive envelope.

17. A power converter comprising a feedback or feedforward control means, means for continuously sensing an inductor current and means for continuously deriving an input and/or output voltage therefrom, and means for inputting said derived input and/or output voltage to said feedback or feedforward control means.

18. A power converter as claimed in claim 17 wherein said means for deriving an output voltage comprises, means for converting an inductor current to an inductor voltage comprising:

(a) means for continuously determining an instantaneous inductance,

(b) means for continuously determining a rate of change of said inductor current,

(c) means for multiplying said inductor current by an inductor resistance,

(d) means for generating a product of the output of (a) and (b), and

(e) means for summing the outputs of (c) and (d).

19. A power converter as claimed in claim 18 wherein the output of said inductor current to inductor voltage converting means comprises a positive envelope and a negative envelope and wherein said output deriving means comprises means for demodulating said envelopes.