Battery apparatus with voltage-balancing control and method for controlling the same

• US 10,141,750 B2
• Filed: 05/24/2017
• Issued: 11/27/2018
• Est. Priority Date: 01/24/2017
• Status: Active Grant

• Current Assignee: Cyberpower Systems Incorporated
• Original Assignee: Cyberpower Systems Incorporated
• Inventors: Hsieh, Hung-Ming, Peng, Yung-Hao, Tang, Shih-Chien
• Primary Examiner(s): Garbowski, Leigh M
• Application Number:
  US15/603,553
• Publication Number:
  US 20180212441A1
• Time in Patent Office: 552 Days
• Field of Search: None
• CPC Class Codes: H02J 7/00041 in response to measured battery parameters, e.g. voltage, current or temperature profile
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]

Abstract

A battery apparatus with voltage-balancing control and a method controlling the same employ a voltage-balancing module, which balances voltage values of multiple series-connected batteries of the battery apparatus, and accumulates voltage difference values of each battery relative to reference voltage values to adjust an allowable discharge control parameter Duty for each battery. By virtue of a cycle for updating the Duty, voltage differences of the multiple series-connected batteries can be lowered below a preset value.

Claims

1. A battery apparatus with voltage-balancing control, comprising:

multiple series-connected batteries connected in series to a DC (Direct Current) interface, and charged thereto and discharging therefrom via the DC interface;

a voltage-balancing module having a processor, multiple voltage-balancing control circuits and multiple voltage detection circuits; and

a voltage detection cable assembly having multiple voltage detection cables and a ground cable;

wherein

the voltage-balancing module detects voltage of the multiple series-connected batteries by virtue of the multiple voltage detection cables and the ground cable;

each voltage detection circuit serves to detect a voltage value Vn of a respective one of the series-connected batteries;

the processor of the voltage-balancing module calculates an allowable discharge control parameter Duty of each battery and controls a corresponding voltage-balancing circuit to perform battery discharge of the battery according to the allowable discharge control parameter Duty for voltage of the series-connected batteries to be balanced, and equation for calculating the allowable discharge control parameter Duty of each battery is given by;

Duty=Kp*Vdiff1+Ki*V(t)

where

Duty is a time duration while battery discharge of the corresponding battery is continuously activated and is controllable through pulse width modulation (PWM);

Kp and Ki are engineering parameters;

equation for calculating a first voltage difference value Vdiff1 is;

Vdiff1=Vn−

Vref1;

equation for calculating a voltage value at a time t, V(t), is;

V(t)=∫

₀^tVdiff 2;

equation for calculating a second voltage difference value Vdiff2 is;

Vdiff2=Vn−

Vref2; and

Vref1 and Vref2 are a first reference voltage value and a second reference voltage value respectively.

2. The battery apparatus as claimed in claim 1, wherein

equation for calculating the first reference voltage value Vref1 is Vref1=Vmin, wherein Vmin is a minimum value of the multiple voltage values Vn;

and

equation for calculating the second reference voltage value Vref2 is Vref2=Vmin+Voffset, wherein a value of Voffset ranges from 0 to 100 mV;

Kp is a constant of proportionality;

Ki is a constant of integration; and

a cycle for updating each Duty is a time duration from 1 second to 1 minute.

3. The battery apparatus as claimed in claim 1, wherein

equation for calculating the first reference voltage value Vref1 and the second reference voltage value Vref2 is Vref1=Vref2=Vave, wherein Vave is an average value of the voltage values Vn of the series-connected batteries;

Kp is a constant of proportionality;

Ki is a constant of integration; and

a cycle for updating each Duty is in a time duration from 1 second to 1 minute.

4. The battery apparatus as claimed in claim 1, wherein the multiple series-connected batteries are connected in series to each other through a power cable assembly and multiple series-connected cables, wherein

the power cable assembly has:

a power connector assembly electrically connected to the DC interface;

at least one first power cable electrically connected to a positive electrode of a first one of the series-connected batteries;

at least one second power cable electrically connected to a negative electrode of a Nth one of the series-connected batteries, wherein N is an integer; and

the series-connected cables used to connect the series-connected batteries in series.

5. The battery apparatus as claimed in claim 4, wherein the power connector assembly is integrally formed with a case or includes at least one first power connector and at least one second power connector, and the multiple series-connected batteries are received in a battery box with the power cable assembly extending outwards beyond the battery box.

6. The battery apparatus as claimed in claim 1, wherein a first one of the voltage detection cables is electrically connected to a positive electrode of a first one of the series-connected batteries and a first line of the voltage-balancing module, a second one of the voltage detection cables is electrically connected to a negative electrode of the first one of the series-connected batteries and a second line of the voltage-balancing module, and a third one of the voltage detection cables is electrically connected to a negative electrode of the second one of the series-connected batteries and a third line of the voltage-balancing module.

7. The battery apparatus as claimed in claim 6, wherein a first one of the voltage-balancing control circuits is electrically connected to the first line and the second line of the voltage-balancing module, a first one of the voltage detection circuits is electrically connected to the first line and the second line of the voltage-balancing module, a second one of the voltage-balancing control circuits is electrically connected to the second line and the third line of the voltage-balancing module, and a second one of the voltage detection circuits is electrically connected to the second line and the third line of the voltage-balancing module.

8. The battery apparatus as claimed in claim 1, wherein

the voltage-balancing module has a DC to DC circuit to supply power to the processor;

and

a ground line of the voltage-balancing module is electrically connected to a negative electrode of a Nth one of the series-connected batteries through the ground cable of the voltage detection cable assembly, and the multiple voltage-balancing control circuits and the multiple voltage detection circuits are connected to the ground line.

9. The battery apparatus as claimed in claim 1, wherein

the DC interface is installed in an uninterruptible power supply (UPS), wherein the UPS includes:

an AC (Alternating Current) input terminal connected to the mains power;

a battery charger charging the multiple series-connected batteries through the DC interface;

a DC to AC inverter;

a switch;

an AC output terminal; and

an MCU (Microcontroller Unit);

a surge suppressor; and

a filter;

wherein the voltage-balancing module balances voltage of the multiple series-connected batteries, in case of power outage or breakdown, the MCU controls the switch to connect the DC to AC inverter and the AC output terminal, and a discharge path of the multiple series-connected batteries sequentially goes through the DC interface, the DC to AC inverter, the switch and the AC output terminal, and when the mains power recovers, the MCU restores an original state of the switch to establish a mains power supply path sequentially going through the AC input terminal, the surge suppressor, the filter and the AC output terminal.

10. The battery apparatus as claimed in claim 9, wherein the voltage-balancing module further has a communication port, and the MCU of the UPS is connected to an indicator to display voltage-balancing status or voltage-balancing information, the voltage-balancing status or the voltage-balancing information includes the voltage value and the allowable discharge control parameter Duty of each series-connected battery.

11. The battery apparatus as claimed in claim 1, wherein the first one of the voltage detection cables is electrically connected to the positive electrode of the first one of the series-connected batteries and the first line of the voltage-balancing module, the second one of the voltage detection cables is electrically connected to the positive electrode of the second one of the series-connected batteries and the second line of the voltage-balancing module, and the third one of the voltage detection cables is electrically connected to the positive electrode of the third one of the series-connected batteries and the third line of the voltage-balancing module.

12. A method for controlling a battery apparatus with voltage-balancing control, the battery apparatus having multiple series-connected batteries and a voltage-balancing module, wherein the voltage-balancing module has a processor, multiple voltage-balancing control circuits and multiple voltage detection circuits, the method comprising steps of:

detecting multiple voltage values Vn of the respective series-connected batteries through the multiple voltage detection circuits;

calculating a first voltage difference value Vdiff1 of each series-connected battery through the processor, wherein equation for calculating the Vdiff1 is Vdiff1=Vn−

Vref1, and equation for calculating the value Vref1 is Vref1=Vmin, where Vmin is a minimum of the multiple voltage values Vn of the series-connected batteries;

calculating a second voltage difference value Vdiff2 of each series-connected battery through the processor, wherein equation for calculating the Vdiff2 is Vdiff2=Vn−

Vref2, and equation for calculating the Vref2 is Vref2=Vmin+Voffset, wherein Voffset is a design value;

calculating a voltage value V(t) at a time t of each series-connected battery through the processor, wherein equation for calculating the V(t) is V(t)=∫

₀^tVdiff 2 and V(t) is an accumulated value of every calculation since the beginning;

calculating an allowable discharge control parameter Duty of each series-connected battery through the processor, wherein equation for calculating Duty of each series-connected battery is Duty=Kp*Vdiff1+Ki*V(t), wherein Kp and Ki are engineering constants, and each Duty is a time duration while battery discharge of a corresponding battery is continuously activated and is controllable by way of pulse width modulation (PWM);

controlling the multiple voltage-balancing control circuits to perform battery discharge of the series-connected batteries through the processor to balance the voltage values of the series-connected batteries; and

repeating the foregoing steps to update each Duty until a difference between each two of the multiple series-connected batteries is lowered below a preset value.

13. The method as claimed in claim 12, wherein

the Voffset ranges from 0 to 100 mV;

Kp is a constant of proportionality;

Ki is a constant of integration; and

a cycle for updating each Duty is in a time duration from 1 second to 1 minute.

14. A method for controlling a battery apparatus with voltage-balancing control, the battery apparatus having multiple series-connected batteries and a voltage-balancing module, wherein the voltage-balancing module has a processor, multiple voltage-balancing control circuits and multiple voltage detection circuits, the method comprising steps of:

detecting multiple voltage values Vn of the respective series-connected batteries through the multiple voltage detection circuits;

calculating a first voltage difference value Vdiff1 of each series-connected battery through the processor, wherein equation for calculating the Vdiff1 is Vdiff1=Vn−

Vref1, and equation for calculating the value Vref1 is Vref1=Vave, wherein Vave is an average voltage value of the multiple series-connected batteries;

calculating a second voltage difference value Vdiff2 of each series-connected battery through the processor, wherein equation for calculating the Vdiff2 is Vdiff2=Vn−

Vref2, and equation for calculating the Vref2 is Vref2=Vave;

calculating a voltage value V(t) at a time t of each series-connected battery through the processor, wherein equation for calculating the V(t) is V(t)=∫

₀^tVdiff 2 and V(t) is an accumulated value of every calculation since the beginning;

calculating an allowable discharge control parameter Duty of each series-connected battery through the processor, wherein equation for calculating Duty of each series-connected battery is Duty=Kp*Vdiff1+Ki*V(t), wherein Kp and Ki are engineering constants, and each Duty is a time duration while battery discharge of a corresponding battery is continuously activated and is controllable by way of pulse width modulation (PWM);

controlling the multiple voltage-balancing control circuits to perform battery discharge of the series-connected batteries through the processor to balance the voltage values of the series-connected batteries; and

repeating the foregoing steps to update each Duty until a difference between each two of the multiple series-connected batteries is lowered below a preset value.

15. The method as claimed in claim 14, wherein

Kp is a constant of proportionality;

Ki is a constant of integration; and

a cycle for updating each Duty is in a time duration from 1 second to 1 minute.