UAV hybrid power systems and methods

• US 10,501,195 B2
• Filed: 03/31/2017
• Issued: 12/10/2019
• Est. Priority Date: 12/31/2015
• Status: Active Grant

• Current Assignee: SZ DJI Technology Co., Ltd. (d/b/a DJI) (iFlight Technology Company Limited)
• Original Assignee: SZ DJI Technology Co., Ltd. (d/b/a DJI) (iFlight Technology Company Limited)
• Inventors: Wang, Lei, Wang, Wentao, Zheng, Dayang, Zhan, Juncheng, Liu, Yuancai
• Primary Examiner(s): Amaya, Carlos
• Application Number:
  US15/476,583
• Publication Number:
  US 20170203850A1
• Time in Patent Office: 984 Days
• Field of Search: 307 91
• CPC Class Codes: B64C 39/024 of the remote controlled vehicle type, i.e. RPV
• CPC Class Codes: B64D 2041/005 Fuel cells
• CPC Class Codes: B64D 2221/00 Electric power distribution systems onboard aircraft
• CPC Class Codes: B64D 27/24 using steam or spring force jet aircraft B64D27/16
• CPC Class Codes: B64D 27/353 using solar cells
• CPC Class Codes: B64D 41/00 Power installations for auxiliary purposes
• CPC Class Codes: B64U 10/13 Flying platforms
• CPC Class Codes: B64U 10/14 with four distinct rotor axes, e.g. quadcopters
• CPC Class Codes: B64U 30/20 Rotors; Rotor supports
• CPC Class Codes: B64U 50/19 using electrically powered motors
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators

Abstract

Systems, methods, and devices are provided herein for improving the power performance of vehicle. A hybrid power system may comprise a power controller adapted to be in communication with a first power source, a second power source, and a load. The power controller may be configured to detect whether a current drawn by the load exceeds a predetermined threshold, control discharging of the first power source without permitting discharging of the second power source to power the load when the current drawn by the load is less than the predetermined threshold current, and control discharging of the first power source and the second power source to power the load when the current drawn by the load is greater than the predetermined threshold current.

Claims

1. A hybrid power system comprising:

a current sensor configured to detect whether a current drawn by a load exceeds a predetermined threshold current;

a first switch disposed between a first power source and the load;

a second switch disposed between the first power source and a second power source;

a third switch disposed between the second power source and the load; and

a power controller adapted to be in communication with the first power source, the second power source, the current sensor, the first switch, the second switch, the third switch, and the load, wherein the power controller is configured to;

in response to the current sensor detecting that the current drawn by the load is less than the predetermined threshold current, turn on the first switch and turn off the third switch to control discharging of the first power source without permitting discharging of the second power source to power the load; and

in response to the current sensor detecting that the current drawn by the load is greater than the predetermined threshold current, turn on the first switch and the second switch to control discharging of the first power source and the second power source to power the load.

2. The hybrid power system of claim 1, wherein the hybrid power system is located on an unmanned aerial vehicle (UAV).

3. The hybrid power system of claim 2, wherein the load comprises a motor system of the UAV, the motor system being configured to provide a propulsion for the UAV.

4. The hybrid power system of claim 1, wherein the first power source is configured to discharge at a voltage V1 and a current I1 to power the load, wherein the predetermined threshold current corresponds to the current I1 of the first power source, wherein the current drawn by the load is I0 when the current drawn by the load is less than the predetermined threshold current, and wherein the current drawn by the load is I(h) when the current drawn by the load is greater than the predetermined threshold current, wherein the power controller is configured to control the discharging of the first power source and the second power source to power the load when the current drawn by the load is greater than the predetermined threshold current, such that the first power source discharges the current I1 to the load, and the second power source discharges a boost current I(b) to the load, and wherein the boost current I(b) corresponds to a difference between the current I(h) and the current I1.

5. The hybrid power system of claim 4, wherein the second power source has a power density such that the second power source is capable of discharging the boost current I(b) to supplement the current I1 discharged by the first power source when the current drawn by the load is greater than the predetermined threshold current.

6. The hybrid power system of claim 5, wherein the power density of the second power source is higher than the power density of the first power source.

7. The hybrid power system of claim 4, wherein an energy capacity density of the first power source is higher than an energy capacity density of the second power source.

8. The hybrid power system of claim 1, further comprising:

a third power source, and wherein the power controller is adapted to be in communication with the first power source, the second power source, the third power source, and the load, wherein the power controller is further configured to;

control discharging of the first power source and the second power source without permitting discharging of the third power source to power the load when the current drawn by the load is greater than the predetermined threshold current and less than a first predetermined threshold current; and

control discharging of the first power source, the second power source, and the third power source to power the load when the current drawn by the load is greater than the first predetermined threshold current.

9. The hybrid power system of claim 8, wherein the first power source is a fuel cell, the second power source is a lithium-ion battery, and the third power source is a super capacitor.

10. The hybrid power system of claim 9, wherein the power controller is further adapted to be in communication with a fourth power source, and wherein the fourth power source is a solar cell.

11. The hybrid power system of claim 8, wherein the first power source is configured to discharge at a voltage V1 and a current I1 to power the load, wherein the predetermined threshold current corresponds to the current I1 of the first power source, wherein the first predetermined threshold current corresponds to a current I2, wherein the current drawn by the load is I0 when the current drawn by the load is less than the predetermined threshold current, and wherein the current drawn by the load is I(h) when the current drawn by the load is greater than the predetermined threshold current.

12. The hybrid power system of claim 11, wherein the power controller is configured to control the discharging of the first power source and the second power source to power the load when I(h)≤

I2, such that the first power source discharges the current I1 to the load, and the second power source discharges a first boost current I(b1) to the load, wherein the first boost current I(b1) corresponds to a difference between the current I(h) and the current I1.

13. The hybrid power system of claim 12, wherein the second power source has a power density such that the second power source is capable of discharging the first boost current I(b1) to supplement the current I1 discharged by the first power source when I(h)≤

I2.

14. The hybrid power system of claim 12, wherein the first predetermined threshold current I2 is set to less than or equal to about twice the value of the predetermined threshold current I1, in order to maintain performance and battery life of the second power source.

15. A hybrid power system comprising:

a power controller adapted to be in communication with a first power source, a second power source, a third power source and a load, the power controller being configured to;

detect whether a current drawn by the load exceeds a predetermined threshold current;

control discharging of the first power source without permitting discharging of the second power source and the third power source to power the load when the current drawn by the load is less than the predetermined threshold current;

control discharging of the first power source and the second power source without permitting discharging of the third power source to power the load when the current drawn by the load is greater than the predetermined threshold current and less than a first predetermined threshold current; and

control discharging of the first power source, the second power source, and the third power source to power the load when the current drawn by the load is greater than the first predetermined threshold current;

wherein;

the first power source is configured to discharge at a voltage V1 and a current I1 to power the load;

the predetermined threshold current corresponds to the current I1 of the first power source;

the first predetermined threshold current corresponds to a current I2;

the current drawn by the load is I0 when the current drawn by the load is less than the predetermined threshold current;

the current drawn by the load is I(h) when the current drawn by the load is greater than the predetermined threshold current; and

the power controller is configured to;

control the discharging of the first power source and the second power source to power the load when I(h)≤

I2, such that the first power source discharges the current I1 to the load, and the second power source discharges a first boost current I(b1) to the load, wherein the first boost current I(b1) corresponds to a difference between the current I(h) and the current I1; and

control the discharging of the first power source, the second power source, and the third power source to power the load when I(h)>

I2, such that the first power source discharges the current I1 to the load, the second power source discharges the first boost current I(b1) to the load, and the third power source discharges a second boost current I(b2) to the load, wherein the second boost current I(b2) is calculated using the following equation;

I(b2)=I(h)−

I(b1)−

I1.

16. The hybrid power system of claim 15, wherein the third power source has a power density such that the third power source is capable of discharging the second boost current I(b2) to the load to supplement the current I1 discharged by the first power source and the first boost current I(b1) discharged by the second power source when I(h)>

I2.

17. An unmanned aerial vehicle (UAV) comprising:

a load comprising at least one propulsion unit;

a current sensor configured to detect whether a current drawn by the load exceeds a predetermined threshold current;

a first switch disposed between a first power source and the load;

a second switch disposed between the first power source and a second power source;

a third switch disposed between the second power source and the load; and

a power controller adapted to be in communication with the first power source, the second power source, the current sensor, the first switch, the second switch, the third switch, and the load, wherein the power controller is configured to;

turn on the first switch and turn off the third switch to control discharging of the first power source without permitting discharging of the second power source to power the load when the current drawn by the load is less than the predetermined threshold current; and

turn on the first switch and the second switch to control discharging of the first power source and the second power source to power the load when the current drawn by the load is greater than the predetermined threshold current.

18. The UAV according to claim 17, wherein the power density of the second power source is higher than the power density of the first power source.

19. The UAV according to claim 17, wherein an energy capacity density of the first power source is higher than an energy capacity density of the second power source.