Digital controller with nested loops for switched mode power converter

Patent metadata

Field	Value
Publication number	US-9461536-B2
Application number	US-201314092590-A
Country	US
Kind code	B2
Filing date	Nov 27, 2013
Priority date	Nov 27, 2013
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

In one example, a method includes receiving a voltage value and comparing the voltage value to a reference voltage value to determine a delta voltage value. The method may also include determining a reference current value based on the delta voltage value. The method may also include receiving a current value and comparing the current value to the reference current value to determine a delta current value. The method may also include determining a threshold value based on the delta current value, where the threshold value is used to define a control signal that controls a power converter.

First claim

The invention claimed is:

1. A method comprising:
receiving a voltage value that corresponds to a voltage across a load electrically coupled to an output of a power converter during a first time period;
comparing the voltage value to a reference voltage value to determine a delta voltage value;
determining a reference current value based on the delta voltage value;
receiving a current value that corresponds to a current flowing to the load during the first time period;
comparing the current value to the reference current value to determine a delta current value; and
determining a threshold value based on the delta current value, wherein the threshold value is used to define a control signal that controls the power converter during a second time period that is different than the first time period.

2. The method of claim 1 , wherein the load comprises at least one of a battery and a device.

3. The method of claim 2 , wherein the battery comprises a plurality of cells, wherein receiving a voltage value comprises receiving a plurality of voltage values, and wherein the plurality of voltage values respectively correspond to voltages across the plurality of cells of the battery, further comprising:
selecting a voltage value from the plurality of voltage values, wherein comparing the voltage value to the reference voltage value to determine the delta voltage value comprises comparing the selected voltage value to the reference voltage to determine the delta voltage value.

4. The method of claim 3 , wherein selecting the voltage value from the plurality of voltage values comprises selecting the greatest voltage value from the plurality of voltage values.

5. The method of claim 1 , wherein determining the reference current value based on the delta voltage value comprises applying a non-linear gain to the delta voltage value.

6. The method of claim 5 , wherein the threshold value is a first threshold value, and wherein applying the non-linear gain to the delta voltage value comprises applying a first gain level to the delta voltage value where the delta voltage value is greater than a second threshold value and applying a second gain level to the delta voltage value where the delta voltage value is less than the second threshold value.

7. The method of claim 6 , wherein the first gain level is greater than the second gain level.

8. The method of claim 6 , wherein the second threshold value is zero.

9. The method of claim 1 , wherein determining the reference current value based on the delta voltage value comprises integrating the delta voltage value to determine the reference current value.

10. The method of claim 1 , further comprising restricting the reference current value such that the reference current value is greater than a minimum value and lesser than a maximum value, wherein the minimum value is an end of charge current level and the maximum value is a maximum current at which a battery electrically coupled to an output of the power converter can be charged.

11. The method of claim 1 , wherein receiving the current value comprises:
receiving an analog current sample; and
converting the analog current sample into a digital current value, wherein comparing the current value to the reference current value to determine a delta current value comprises comparing the digital current value to the reference current value to determine a delta current value, and wherein receiving the voltage value from the power converter comprises:
receiving an analog voltage sample; and
converting the analog voltage sample into a digital voltage value, wherein comparing the voltage value to the reference voltage to determine the delta voltage value comprises comparing the digital voltage value to the reference voltage to determine the delta voltage value.

12. The method of claim 1 , wherein comparing the current value to the reference current value to determine the delta current value comprises subtracting the reference current value from the current value to determine the delta current value.

13. The method of claim 1 , wherein determining the threshold value based on the delta current value comprises determining the threshold value based on the delta current value with a proportional-integral (PI) controller.

14. The method of claim 1 , wherein the control signal is a pulse-width modulated (PWM) signal, further comprising:
generating the PWM signal based on the threshold value; and
outputting the PWM signal to the power converter.

15. The method of claim 1 , wherein determining the reference current value based on the delta voltage value further comprises determining the reference current value based on the delta voltage value and at least one of an input current of the power converter and a temperature of a battery electrically coupled to an output of the power converter.

16. The method of claim 1 , further comprising:
determining the reference voltage value based on at least one of an input current of the power converter, a temperature of a battery electrically coupled to an output of the power converter, and a state of charge of the battery.

17. The method of claim 1 , further comprising:
determining a minimum value based on at least one of an input current of the power converter, a temperature of a battery electrically coupled to an output of the power converter, and a state of charge of the battery; and
restricting the reference current value such that the reference current value is greater than the minimum value and lesser than a maximum value.

18. The method of claim 1 , wherein the power converter is a multi-phase power converter.

19. A circuit comprising:
a first analog to digital converter configured to convert an analog voltage sample into a digital voltage value;
a first subtractor configured to subtract a reference voltage from the digital voltage value to determine a delta voltage value;
an integrator configured to integrate the delta voltage value to determine a reference current value;
a second analog to digital converter configured to convert an analog current sample received from the power converter into a digital current value;
a second subtractor configured to subtract the reference current value from the digital current value to determine a delta current value;
a controller configured to determine a threshold value based on the delta current value; and
a digital pulse width modulator configured to output, to a power converter, a control signal based on the threshold value.

20. The circuit of claim 19 ,
wherein the voltage value corresponds to a voltage across a load electrically coupled to an output of the power converter,
wherein the current value corresponds to a current flowing through the load,
wherein the load comprises a battery,
wherein the battery comprises a plurality of cells,
wherein the first analog to digital converter is configured to convert a plurality of analog voltage samples received from the power converter into a plurality of digital voltage values,
wherein the plurality of voltage values respectively correspond to voltages across the plurality of cells of the battery,
the circuit further comprising:
a selector configured to select a cell voltage value from the plurality of digital voltage values,
wherein the first subtractor is configured to subtract the reference voltage from the selected cell voltage value to determine the delta voltage value.

21. The circuit of claim 19 , further comprising:
an amplifier configured to apply a non-

Assignees

• Infineon Technologies Austria Ag

Inventors

• Bizjak Luca
• Marsili Stefano
• Riederer Roman
• Perissakis Stylianos

Classifications

• H02J7/96

  in response to battery voltage · CPC title

• H02J7/94

  in response to battery current · CPC title

• H02J7/977 Primary

  of the battery · CPC title

• H02M3/156

  with automatic control of output voltage or current, e.g. switching regulators · CPC title

• H02J7/92 Primary

  with prioritisation of loads or sources · CPC title