Controllers for battery chargers and battery chargers therefrom

• US 8,773,077 B1
• Filed: 03/04/2011
• Issued: 07/08/2014
• Est. Priority Date: 03/05/2010
• Status: Active Grant

• Current Assignee: Advanced Power Electronics Corp., University of Central Florida Research Foundation Inc. (State University System of Florida)
• Original Assignee: Advanced Power Electronics Corp., University of Central Florida Research Foundation Inc. (State University System of Florida)
• Inventors: Pepper, Michael, Elmes, John, Kersten, Rene
• Primary Examiner(s): DIAO, M BAYE
• Application Number:
  US13/041,164
• Time in Patent Office: 1,222 Days
• Field of Search: 320/128, 320/140, 320/141, 320/144, 320/145
• US Class Current: 320/145
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 2300/26 involving maximum power point tracking control for photovoltaic sources maximum power point systems in particular G05F1/67
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/007192 in response to temperature
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

A controller for a battery charger that includes a power converter has parametric sensors for providing a sensed Vin signal, a sensed Vout signal and a sensed Iout signal. A battery current regulator (BCR) is coupled to receive the sensed Iout signal and an Iout reference, and outputs a first duty cycle control signal. An input voltage regulator (IVR) receives the sensed Vin signal and a Vin reference. The IVR provides a second duty cycle control signal. A processor receives the sensed Iout signal and utilizes a Maximum Power Point Tracking (MPPT) algorithm, and provides the Vin reference to the IVR. A selection block forwards one of the first and second duty cycle control signals as a duty cycle control signal to the power converter. Dynamic switching between the first and second duty cycle control signals maximizes the power delivered to the battery.

Claims

1. A controller block for a battery charger including a power converter, comprising:

a plurality of parametric sensors for providing a plurality of sensed parameters provided by said power converter while said power converter is connected between a power source and at least one battery for charging said battery, said sensed parameters including a sensed Vin signal, a sensed Vout signal and a sensed Iout signal;

a battery current regulator (BCR) coupled to receive said sensed Iout signal and an Iout reference, said BCR outputting a first duty cycle control signal;

an input voltage regulator (IVR) for receiving said sensed Vin signal and a Vin reference, said IVR providing a second duty cycle control signal;

a processor coupled to receive said sensed Iout signal, said processor utilizing a Maximum Power Point Tracking (MPPT) algorithm for providing said Vin reference to said IVR, and

a selection block coupled to receive said first and said second duty cycle control signals, said selection block forwarding one of said first and said second duty cycle control signals as a duty cycle control signal to said power converter.

2. The controller block of claim 1, wherein said first and said second duty cycle control signals implement both battery current regulation and said MPPT, respectively.

3. The controller block of claim 1, further comprising an output voltage regulator (OVR) coupled to receive said Vout for generating said Iout reference, wherein an output of said OVR is coupled to provide said Iout reference to said BCR to implement charge control for said battery.

4. A battery charger, comprising:

a power converter coupled to receive an input voltage (Vin) from a power source and provide an output voltage (Vout) and a battery charging current (Iout) to charge one or more batteries;

a controller block having an output that provides a duty cycle control signal for said power converter coupled to a control input of said power converter, said controller block comprising;

a plurality of parametric sensors for providing a plurality of sensed parameters including a sensed Vin signal, a sensed Vout signal and a sensed Iout signal;

a battery current regulator (BCR) coupled to receive said sensed Iout signal and an Iout reference, said BCR outputting a first duty cycle control signal;

an input voltage regulator (IVR) for receiving said sensed Vin signal and a Vin reference, said IVR providing a second duty cycle control signal;

a processor coupled to receive said sensed Iout signal, said processor utilizing a Maximum Power Point Tracking (MPPT) algorithm for providing said Vin reference to said IVR, and

a selection block coupled to receive said first and said second duty cycle control signals, said selection block forwarding one of said first and said second duty cycle control signals as said duty cycle control signal to said power converter.

5. The battery charger of claim 4, wherein said plurality of parametric sensors are exclusive of an input current sensor.

6. The battery charger of claim 4, wherein said selection block implements a minimum function to select a lower in magnitude of said first and said second duty cycle control signals.

7. The battery charger of claim 4, wherein said first and said second duty cycle control signals implement both battery current regulation and said MPPT, respectively.

8. The battery charger of claim 4, wherein said power converter comprises a Pulse Width Modulation (PWM) controlled DC-DC converter.

9. The battery charger of claim 4, further comprising an output voltage regulator (OVR) coupled to receive said Vout for generating said Iout reference, wherein an output of said OVR is coupled to provide said Iout reference to said BCR to implement charge control for said battery.

10. A method of charging batteries using a battery charger that includes a switched power converter disposed between a power source and a battery that provides input power at an input voltage (Vin), said power converter generating an output voltage (Vout) and a battery current (Iout), comprising:

sensing parameters using a plurality of parametric sensors including a sensed Vin signal, a sensed Vout signal and a sensed Iout signal;

generating a first duty cycle control signal from said sensed Iout signal and an Iout reference;

generating a second duty cycle control signal from said sensed Vin signal and a Vin reference;

selecting between said first and said second duty cycle control signals, and

forwarding one of said first and said second duty cycle control signals as a duty cycle control signal to said power converter.

11. The method of claim 10, further comprising a soft-start procedure which increases a battery voltage reference linearly to a battery charge voltage defined by a battery charging algorithm that modifies said Iout reference, including a temporary pause of said soft-start procedure while said battery is connected to allow charging, so as to allow for control logic and analog switching delays.

12. The method of claim 10, wherein said selecting implements a minimum function to select a lower in magnitude of said first and said second duty cycle control signals.

13. The method of claim 10, wherein said first and said second duty cycle control signals implement battery current regulation and said MPPT, respectively.

14. The method of claim 10, wherein said switched power converter comprises a battery current regulator (BCR) coupled to receive said sensed Iout signal and said Iout reference, said BCR outputting said first duty cycle control signal and an input voltage regulator (IVR) for receiving said sensed Vin signal and said Vin reference, said IVR providing said second duty cycle control signal, and a selection block for said selecting between said first and said second duty cycle control signals;

said method further comprising adjusting an output of said BCR and said IVR to equal a current duty cycle being commanded by said selection block at a time one of said BCR and IVR is transitioning from a saturated state to an active state while the other of said BCR and said IVR is selected by said selection block.

15. The method of claim 14, further comprising regulating a maximum output voltage of said battery with an Output Voltage Regulator (OVR), wherein said OVR is coupled to a voltage sense of said battery to define an upper saturation limit of said BCR to limit said maximum output voltage of said battery.

16. The method of claim 14, further comprising implementing a Temperature Current Limiter (TCL) function that commands a Maximum Charge Current (MCC) of said battery charger as commanded to said BCR to define a linear reduction in current as a sensed temperature of said battery charger lies beyond the pre-determined safe operating temperature of said battery charger.

17. The method of claim 14, further comprising preventing a collapse of said Vin during transitions between operation of said IVR and BCR, comprising:

a Minimum Input Equation (MIE) which calculates a minimum input voltage (MIV) needed to operate said power converter, and

a Minimum Input Voltage (MIV) function which clamps said Vin to a minimum input voltage set by said MIE by preventing said duty cycle selected by said selecting from increasing whenever said sensed Vin signal is equal to or less than said MIV.

18. The method of claim 17, further comprising implementing a Maximum Power Point Tracking (MPPT) algorithm that modifies said Vin reference so as to maximize said Iout, said MPPT having an enable and a disable state, wherein:

said disabled state resets said Vin reference to a minimum operational input voltage as commanded by said MIE; and

said enabled state actively varies said Vin reference to achieve a maximum charging current by monitoring said Iout, and varying said Vin reference to increase captured energy from said power source.

19. The method of claim 15, further comprising sensing a battery voltage, and a battery current of said battery, and changing regulation setpoints for said OVR and said BCR based on at least one of said battery voltage and said battery current.

20. The method of claim 19, further comprising sensing a temperature of said battery, and changing regulation setpoints for said OVR and said BCR based on said temperature.