Battery boosting circuit and method

Abstract

The invention discloses a battery boosting circuit and method, and belongs to the technical field of electric energy conversion, the battery boosting circuit comprises a direct current-direct current conversion unit, a first capacitor and a first switch, the input end of the direct current-direct current conversion unit is connected with a battery in parallel, and the output end of the direct current-direct current conversion unit is connected with the first capacitor in parallel; the first switch is connected with the first capacitor in parallel, and the first capacitor is connected with the battery in series. According to the battery boosting circuit and method, the battery can be boosted to meet the range of normal working voltage; as the booster works in series with the battery, the power needing to be treated is only the power of the booster part, and the power needing to be treated is smaller, the design is simpler, the loss is smaller, and the heat treatment is easier; and as the power is greatly reduced, the cost is better, and the practicability is high.

Description

Technical Field

[0001] The present invention relates to the technical field of electric energy conversion, and in particular to a battery boosting circuit and method. Background Art

[0002] In the application of sodium battery driven two-wheeled electric bicycles, since the voltage range of the sodium battery is wide, in order to match the operating voltage range of the motor, when the sodium battery voltage decreases, the battery voltage needs to be increased to the normal operating voltage range of the motor controller. Summary of the invention

[0003] The present invention aims to provide a battery boost circuit and method, so that the output voltage rises to the normal working voltage range of the motor controller.

[0004] To achieve the above object, the technical solution of the present invention is:

[0005] A battery boost circuit includes a DC-DC conversion unit, a first capacitor and a first switch, wherein an input end of the DC-DC conversion unit is connected in parallel with a battery, an output end of the DC-DC conversion unit is connected in parallel with the first capacitor, the first switch is connected in parallel with the first capacitor, and the first capacitor is connected in series with the battery.

[0006] Furthermore, the first switch is a bidirectional switch.

[0007] In a specific embodiment, the DC-DC conversion unit is a non-isolated DC-DC conversion topology, and the first capacitor is connected in series to the negative electrode of the battery.

[0008] More specifically, the DC-DC conversion unit is a CUK conversion topology.

[0009] More specifically, the DC-DC conversion unit is a Buck-Boost conversion topology.

[0010] In a specific embodiment, the DC-DC conversion unit is an isolated DC-DC conversion topology, and the first capacitor is connected in series to the positive electrode of the battery.

[0011] More specifically, the DC-DC conversion unit includes an inverter module, a resonance module, a transformer module, and a rectifier module. The battery, the inverter module, the resonance module, the transformer module, the rectifier module, and the first capacitor are connected in parallel in sequence.

[0012] In a specific embodiment, the bidirectional switch includes two switches connected in reverse series.

[0013] The present invention also provides a battery boosting method, which is applied to the above-mentioned battery boosting circuit, comprising:

[0014] Step S1, sampling the battery voltage and the output voltage of the DC-DC conversion unit;

[0015] Step S2, when the battery voltage is not lower than the voltage setting value, the first switch is closed, and the DC-DC conversion unit is bypassed and does not work;

[0016] Step S3, when the battery voltage is lower than the voltage setting value, the first switch is turned off, the DC-DC conversion unit works, and the drive signal of the switch in the DC-DC conversion unit is adjusted so that the output voltage of the DC-DC conversion unit is equal to the voltage setting value minus the battery voltage.

[0017] The present invention also provides an electric bicycle, comprising the above-mentioned battery boosting circuit, and also comprising a motor controller and a battery, wherein the input end of the battery boosting circuit is connected in parallel with the battery, the output end of the battery boosting circuit is connected in series with the battery, and the two ends of the series connection between the output end of the battery boosting circuit and the battery are connected in parallel with the motor controller.

[0018] Beneficial effect: A battery boosting circuit and method of the present invention can boost the battery to meet the normal working voltage range; because it works in series with the battery, the power that needs to be processed is only the power of the boosting part, and the power that needs to be processed is relatively small, so the design will be simpler, the loss will be smaller, and the heat treatment will be easier; and because the power is greatly reduced, the cost is better and the practicality is strong.

[0019] In order to make the above features and advantages of the invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The figure is a circuit diagram of a first specific embodiment of a battery boosting circuit according to the present invention.

[0021] Figure 2 This is a circuit diagram of a second specific embodiment of a battery boost circuit of the present invention.

[0022] Figure 3 This is a circuit diagram of a third specific embodiment of a battery boost circuit of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose and technical solution of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Figure 1 FIG. 1 is a circuit diagram of a first specific embodiment of a battery boost circuit according to the present invention. Figure 1 As shown, the input end of the battery boost circuit 11 is connected in parallel with the battery VB1, the output end of the battery boost circuit 11 is connected in series with the battery VB1, and the series-connected terminals OUT1 and OUT2 are connected in parallel with the motor controller 12 to provide voltage for the motor controller 12.

[0025] Furthermore, the battery boost circuit 11 includes a DC-DC conversion unit 112, a capacitor C1 and a switch 111, the input end of the DC-DC conversion unit 112 is connected in parallel with the battery VB1, the output end of the DC-DC conversion unit 112 is connected in parallel with the capacitor C1, the switch 111 is connected in parallel with the capacitor C1, the capacitor C1 is connected in series with the battery VB1, the first end of the capacitor C1 is connected to the negative electrode of the battery VB1, the second end of the capacitor C1 is the terminal OUT2, and the positive electrode of the battery VB1 is the terminal OUT1.

[0026] Furthermore, the switch 111 is a bidirectional switch, including two switches Q1 and Q2 connected in series in an anti-reverse manner, wherein the function of the bidirectional switch is to prevent the capacitor C1 from being short-circuited.

[0027] Optionally, the switch Q1 and the switch Q2 are MOSFETs.

[0028] Further, in this specific embodiment, the DC-DC conversion unit 112 is a non-isolated DC-DC conversion topology, specifically a CUK conversion topology, and the DC-DC conversion unit 112 includes an inductor L1, a capacitor C2, a switch Q3, a diode D1 and an inductor L2, a first end of the inductor L1 is connected to the positive electrode of the battery VB1, a second end of the inductor L1 is connected to the first end of the switch Q3, a second end of the switch Q3 is connected to the negative electrode of the battery VB1, a first end of the switch Q3 is connected to the first end of the capacitor C2, a second end of the capacitor C2 is connected to the anode of the diode D1, a cathode of the diode D1 is connected to the negative electrode of the battery VB1, an anode of the diode D1 is connected to the first end of the inductor L2, and a second end of the inductor L2 is connected to the second end of the capacitor C1.

[0029] Next, continue to combine Figure 1The working principle of the present invention is introduced. When the battery VB1 does not need to be pressurized, the switch 111 is turned on, the DC-DC conversion unit 112 is bypassed, and the battery VB1 alone supplies power to the motor controller 12. When the voltage of the battery VB1 does not meet the working voltage range of the motor controller 12 or is lower than the voltage setting value, the switch 111 is disconnected, and the DC-DC conversion unit 112 works, outputting a voltage to both ends of the capacitor C1, and then connected in series with the battery VB1 to supply power to the motor controller 12, so as to meet the working voltage range of the motor controller 12.

[0030] In this specific embodiment, the output of the CUK conversion topology is connected in series to the negative electrode of the battery VB1. Since the output of the CUK conversion topology has a negative voltage characteristic, it can be conveniently connected in series to the negative electrode of the battery to increase the output voltage between the terminal OUT1 and the terminal OUT2. At the same time, since the switch of the CUK conversion topology shares a common ground with the negative electrode of the battery, the drive is relatively simple and reliable.

[0031] Furthermore, as the voltage of the battery VB1 decreases, the output voltage of the DC-DC conversion unit 112 gradually increases, ensuring that the total output voltage after the series connection remains unchanged.

[0032] Figure 2 FIG. 1 is a circuit diagram of a second specific embodiment of a battery boost circuit according to the present invention. Figure 2 As shown, the input end of the battery boost circuit 21 is connected in parallel with the battery VB2, the output end of the battery boost circuit 21 is connected in series with the battery VB2, and the series-connected terminal OUT3 and terminal OUT4 are connected in parallel with the motor controller 22 to provide voltage for the motor controller 22.

[0033] Furthermore, the battery boost circuit 21 includes a DC-DC conversion unit 212, a capacitor C3 and a switch 211, the input end of the DC-DC conversion unit 212 is connected in parallel with the battery VB2, the output end of the DC-DC conversion unit 212 is connected in parallel with the capacitor C3, the switch 211 is connected in parallel with the capacitor C3, the capacitor C3 is connected in series with the battery VB2, the second end of the capacitor C3 is connected to the positive electrode of the battery VB2, the first end of the capacitor C3 is the terminal OUT3, and the negative electrode of the battery VB2 is the terminal OUT4.

[0034] Furthermore, the switch 211 is a bidirectional switch, including two switches Q4 and Q5 connected in series in reverse order, wherein the function of the bidirectional switch is to prevent the capacitor C3 from being short-circuited.

[0035] Optionally, the switch Q4 and the switch Q5 are MOSFETs.

[0036] Furthermore, in this specific embodiment, the DC-DC conversion unit 212 is an isolated DC-DC conversion topology, and the DC-DC conversion unit 212 includes an inverter module 2121, a resonance module 2122, a transformer module 2123, and a rectifier module 2124. The battery VB2, the inverter module 2121, the resonance module 2122, the transformer module 2123, the rectifier module 2124, and the capacitor C3 are connected in parallel in sequence.

[0037] Optionally, the inverter module 2121 includes but is not limited to full-bridge topology, half-bridge topology, hard-switching full-bridge topology, phase-shifted full-bridge topology and other topological structures that can realize the inverter function.

[0038] Optionally, the resonance module 2122 includes but is not limited to LLC resonance topology and other topological structures that can achieve resonance function.

[0039] Optionally, the transformation module 2123 may be a transformer or the like.

[0040] Optionally, the rectifier module 2124 includes but is not limited to a topology structure that can realize a rectification function, such as a full-bridge topology.

[0041] Next, continue to combine Figure 2 The working principle of the present invention is introduced. The output end of the DC-DC conversion unit 212 is connected in series to the positive electrode of the battery VB2. When the battery VB2 does not need to be pressurized, the switch 211 is turned on, the DC-DC conversion unit 212 is bypassed, and the battery VB2 alone supplies power to the motor controller 22. When the voltage of the battery VB2 does not meet the working voltage range of the motor controller 22 or is lower than the voltage setting value, the switch 211 is disconnected, the DC-DC conversion unit 212 works, and outputs voltage to both ends of the capacitor C3, and is connected in series with the battery VB2 to supply power to the motor controller 22, so as to meet the working voltage range of the motor controller 22.

[0042] Furthermore, as the voltage of the battery VB2 decreases, the output voltage of the DC-DC conversion unit 212 gradually increases, ensuring that the total output voltage after the series connection remains unchanged.

[0043] Among them, the isolated DC-DC conversion topology is suitable for occasions with higher output power.

[0044] Figure 3 FIG. 1 is a circuit diagram of a third specific embodiment of a battery boost circuit according to the present invention. Figure 3 As shown, the input end of the battery boost circuit 31 is connected in parallel with the battery VB3, the output end of the battery boost circuit 31 is connected in series with the battery VB3, and the series-connected terminal OUT5 and terminal OUT6 are connected in parallel with the motor controller 32 to provide voltage for the motor controller 32.

[0045] Furthermore, the battery boost circuit 31 includes a DC-DC conversion unit 312, a capacitor C4 and a switch 311, the input end of the DC-DC conversion unit 312 is connected in parallel with the battery VB3, the output end of the DC-DC conversion unit 312 is connected in parallel with the capacitor C4, the switch 311 is connected in parallel with the capacitor C4, the capacitor C4 is connected in series with the battery VB3, the first end of the capacitor C4 is connected to the negative electrode of the battery VB3, the second end of the capacitor C4 is the terminal OUT6, and the positive electrode of the battery VB3 is the terminal OUT5.

[0046] Furthermore, the switch 311 is a bidirectional switch, including two switches Q6 and Q7 connected in series in reverse order, wherein the function of the bidirectional switch is to prevent the capacitor C4 from being short-circuited.

[0047] Optionally, the switch Q6 and the switch Q7 are MOSFETs.

[0048] Furthermore, in this specific embodiment, the DC-DC conversion unit 312 is a non-isolated DC-DC conversion topology, specifically a Buck-Boost conversion topology, and the DC-DC conversion unit 312 includes a switch Q8, an inductor L3 and a diode D2, the first end of the switch Q8 is connected to the positive electrode of the battery VB3, the second end of the switch Q8 is connected to the first end of the inductor L3, the second end of the inductor L3 is connected to the negative electrode of the battery VB3, the cathode of the diode D2 is connected to the first end of the inductor L3, and the anode of the diode D2 is connected to the second end of the capacitor C4.

[0049] Next, continue to combine Figure 3 The working principle of the present invention is introduced. When the battery VB3 does not need to be pressurized, the switch 311 is turned on, the DC-DC conversion unit 312 is bypassed, and the battery VB3 alone supplies power to the motor controller 32. When the voltage of the battery VB3 does not meet the working voltage range of the motor controller 32 or is lower than the voltage setting value, the switch 311 is disconnected, and the DC-DC conversion unit 312 works, outputting a voltage to both ends of the capacitor C4, and then connected in series with the battery VB3 to supply power to the motor controller 32, so as to meet the working voltage range of the motor controller 32.

[0050] In this specific embodiment, the output of the Buck-Boost conversion topology is connected in series to the negative electrode of the battery VB3. Since the output of the Buck-Boost conversion topology has a negative voltage characteristic, it can be conveniently connected in series to the negative electrode of the battery to increase the output voltage between the terminal OUT5 and the terminal OUT6. Compared with the CUK conversion topology, the Buck-Boost conversion topology has fewer components.

[0051] Furthermore, as the voltage of the battery VB3 decreases, the output voltage of the DC-DC conversion unit 312 gradually increases, ensuring that the total output voltage after the series connection remains unchanged.

[0052] The present invention also provides a battery boosting method, which is applied to a battery boosting circuit of the present invention and includes the following steps.

[0053] Step S1, sampling the battery voltage and the output voltage of the DC-DC conversion unit;

[0054] Step S2, when the battery voltage is not lower than the voltage setting value, the switch 111 or the switch 211 or the switch 311 is closed, and the DC-DC conversion unit is bypassed and does not work;

[0055] Step S3, when the battery voltage is lower than the voltage setting value, turn off the switch 111 or the switch 211 or the switch 311, the DC-DC conversion unit works, and adjusts the drive signal of the switch in the DC-DC conversion unit so that the output voltage of the DC-DC conversion unit is equal to the voltage setting value minus the battery voltage.

[0056] More specifically, for Figure 1 and Figure 3 In the embodiment, the control method of output voltage outer loop and inductor current inner loop can be adopted for CUK conversion topology or Buck-Boost conversion topology; in addition, the sampled inductor current can also be used for overcurrent protection.

[0057] The present invention also provides an electric bicycle, comprising the above-mentioned battery boosting circuit, a motor controller and a battery, wherein the output end of the battery boosting circuit is connected in series with the battery and the two ends are connected in parallel with the motor controller.

[0058] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Any person having ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

Claims

1. A battery boost circuit, characterized in that: It includes a DC-DC conversion unit, a first capacitor and a first switch, wherein the input end of the DC-DC conversion unit is connected in parallel with a battery, the output end of the DC-DC conversion unit is connected in parallel with the first capacitor, the first switch is connected in parallel with the first capacitor, and the first capacitor is connected in series with the battery.

2. A battery boost circuit as claimed in claim 1, characterized in that: The first switch is a bidirectional switch.

3. A battery boost circuit as claimed in claim 2, characterized in that: The DC-DC conversion unit is a non-isolated DC-DC conversion topology, and the first capacitor is connected in series to the negative electrode of the battery.

4. A battery boost circuit as claimed in claim 3, characterized in that: The DC-DC conversion unit adopts a CUK conversion topology.

5. A battery boost circuit as claimed in claim 3, characterized in that: The DC to DC conversion unit is a Buck-Boost conversion topology.

6. A battery boost circuit as claimed in claim 2, characterized in that: The DC-DC conversion unit is an isolated DC-DC conversion topology, and the first capacitor is connected in series to the positive electrode of the battery.

7. A battery boost circuit as claimed in claim 6, characterized in that: The DC-DC conversion unit includes an inverter module, a resonance module, a transformer module, and a rectifier module. The battery, the inverter module, the resonance module, the transformer module, the rectifier module, and the first capacitor are connected in parallel in sequence.

8. A battery boost circuit as claimed in claim 2, characterized in that: The bidirectional switch includes two switches connected in series in opposite directions.

9. A battery pressurization method, characterized in that: A battery boost circuit as claimed in any one of claims 1 to 8, comprising: Step S1, sampling the battery voltage and the output voltage of the DC-DC conversion unit; Step S2, when the battery voltage is not lower than the voltage setting value, the first switch is closed, and the DC-DC conversion unit is bypassed and does not work; Step S3, when the battery voltage is lower than the voltage setting value, the first switch is turned off, the DC-DC conversion unit works, and the drive signal of the switch in the DC-DC conversion unit is adjusted so that the output voltage of the DC-DC conversion unit is equal to the voltage setting value minus the battery voltage.

10. An electric bicycle, characterized in that: It comprises a battery boost circuit as described in any one of claims 1 to 8, and also comprises a motor controller and a battery, wherein the input end of the battery boost circuit is connected in parallel with the battery, the output end of the battery boost circuit is connected in series with the battery, and both ends of the output end of the battery boost circuit and the battery in series are connected in parallel with the motor controller.

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