Battery boosting circuit and method

Abstract

This invention discloses a battery boosting circuit and method, belonging to the field of power conversion technology. It includes a DC-DC converter unit, a first capacitor, and a first switch. The input terminal of the DC-DC converter unit is connected in parallel with the battery, and the output terminal of the DC-DC converter 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. This battery boosting circuit and method can boost the battery voltage to meet the normal operating voltage range. Because it operates in series with the battery, the power to be processed is only the power of the boosting section, which is relatively small. Therefore, the design is simpler, with less loss and easier heat treatment. Moreover, due to the significantly reduced power, the cost is lower and the practicality is stronger.

Description

Technical Field

[0001] This invention relates to the field of power conversion technology, and in particular to a battery boosting circuit and method. Background Technology

[0002] In the application of sodium battery-powered two-wheeled electric bicycles, because sodium batteries have a wide voltage range, in order to match the operating voltage range of the motor, the battery voltage needs to be increased to the normal operating voltage range of the motor controller when the sodium battery voltage drops. Summary of the Invention

[0003] The present invention aims to provide a battery boosting circuit and method, which enables the output voltage to rise to the normal operating voltage range of the motor controller.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows:

[0005] A battery boosting circuit includes a DC-DC converter unit, a first capacitor, and a first switch. The input terminal of the DC-DC converter unit is connected in parallel with the battery, the output terminal of the DC-DC converter 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 aforementioned first switch is a two-way switch.

[0007] In one specific embodiment, the DC-DC converter unit is a non-isolated DC-DC converter topology, and the first capacitor is connected in series with the negative terminal of the battery.

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

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

[0010] In one specific embodiment, the DC-DC converter unit is an isolated DC-DC converter topology, and the first capacitor is connected in series with the positive terminal of the battery.

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

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

[0013] The present invention also provides a battery boosting method, applied to the aforementioned battery boosting circuit, comprising,

[0014] Step S1: Sample the battery voltage and the output voltage of the DC-DC converter 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 converter 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 converter unit works, and the drive signal of the switch in the DC-DC converter unit is adjusted so that the output voltage of the DC-DC converter unit is equal to the voltage setting value minus the battery voltage.

[0017] The present invention also provides an electric bicycle, including the aforementioned battery boosting circuit, a motor controller, and a battery. The input terminal of the battery boosting circuit is connected in parallel with the battery, the output terminal of the battery boosting circuit is connected in series with the battery, and the two ends of the series connection between the output terminal of the battery boosting circuit and the battery are connected in parallel with the motor controller.

[0018] Beneficial effects: The present invention provides a battery boosting circuit and method that can boost the voltage of a battery to meet the normal operating voltage range. Since it works in series with the battery, the power that needs to be processed is only the power of the boosting part, which is relatively small. Therefore, the design is simpler, the loss is smaller, and the heat treatment is easier. Moreover, due to the significant reduction in power, the cost is better and the practicality is stronger.

[0019] To make the above-mentioned features and advantages of the invention more apparent and understandable, specific embodiments are described below, and detailed descriptions are provided in conjunction with the accompanying drawings. Attached Figure Description

[0020] Figure 1 This 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 boosting circuit according to the present invention.

[0022] Figure 3 This is a circuit diagram of a third specific embodiment of a battery boosting circuit according to the present invention. Detailed Implementation

[0023] To make the objectives and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

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

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

[0026] Furthermore, the switch 111 is a bidirectional switch, comprising two switches Q1 and Q2 connected in reverse series. The bidirectional switch serves to prevent short-circuiting of the capacitor C1.

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

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

[0029] The following will continue to combine Figure 1The working principle of this invention is described below. When it is not necessary to boost the voltage of the battery VB1, switch 111 is turned on, the DC-DC converter unit 112 is bypassed, and the battery VB1 supplies power to the motor controller 12 alone. When the voltage of the battery VB1 does not meet the operating voltage range of the motor controller 12 or is lower than the voltage setting value, switch 111 is turned off, the DC-DC converter unit 112 operates, and the output voltage is supplied to both ends of the capacitor C1. This voltage, combined with the voltage of the battery VB1, supplies power to the motor controller 12 to meet the operating voltage range of the motor controller 12.

[0030] In this specific embodiment, the output of the CUK converter topology is connected in series to the negative terminal of the battery VB1. Since the output of the CUK converter topology has a negative voltage characteristic, it can be easily connected in series to the negative terminal of the battery to increase the output voltage between terminals OUT1 and OUT2. At the same time, since the switch of the CUK converter topology shares a common ground with the negative terminal 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 converter unit 112 gradually increases, ensuring that the total output voltage after series connection remains unchanged.

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

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

[0034] Furthermore, the switch 211 is a bidirectional switch, comprising two switches Q4 and Q5 connected in reverse series. The bidirectional switch serves to prevent short-circuiting of capacitor C3.

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

[0036] Furthermore, in this specific embodiment, the DC-DC converter unit 212 is an isolated DC-DC converter topology. The DC-DC converter unit 212 includes an inverter module 2121, a resonant module 2122, a transformer module 2123, and a rectifier module 2124. The battery VB2, the inverter module 2121, the resonant 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 may include, but is not limited to, topologies that can realize inverter functions, such as full-bridge topology, half-bridge topology, hard-switching full-bridge topology, and phase-shifting full-bridge topology.

[0038] Optionally, the resonant module 2122 may include, but is not limited to, topologies such as LLC resonant topologies that can achieve resonant function.

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

[0040] Optionally, the rectifier module 2124 may include, but is not limited to, a full-bridge topology or other topology capable of achieving rectification.

[0041] The following will continue to combine Figure 2 The working principle of this invention is described below. The output terminal of the DC-DC converter 212 is connected in series to the positive terminal of the battery VB2. When it is not necessary to boost the voltage of the battery VB2, the switch 211 is turned on, the DC-DC converter 212 is bypassed, and the battery VB2 supplies power to the motor controller 22 alone. When the voltage of the battery VB2 does not meet the operating voltage range of the motor controller 22 or is lower than the voltage setting value, the switch 211 is turned off, the DC-DC converter 212 operates, and the output voltage is supplied to both ends of the capacitor C3. This voltage, along with the battery VB2, supplies power to the motor controller 22 to meet the operating voltage range of the motor controller 22.

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

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

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

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

[0046] Furthermore, the switch 311 is a bidirectional switch, comprising two switches Q6 and Q7 connected in reverse series. The bidirectional switch serves to prevent short-circuiting of the capacitor C4.

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

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

[0049] The following will continue to combine Figure 3 The working principle of this invention is as follows: When it is not necessary to boost the voltage of the battery VB3, switch 311 is turned on, the DC-DC converter unit 312 is bypassed, and the battery VB3 supplies power to the motor controller 32 alone. When the voltage of the battery VB3 does not meet the operating voltage range of the motor controller 32 or is lower than the voltage setting value, switch 311 is turned off, the DC-DC converter unit 312 operates, and the output voltage is supplied to both ends of the capacitor C4. This voltage, combined with the battery VB3, supplies power to the motor controller 32 to meet the operating voltage range of the motor controller 32.

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

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

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

[0053] Step S1: Sample the battery voltage and the output voltage of the DC-DC converter unit;

[0054] Step S2: When the battery voltage is not lower than the voltage setting value, close switch 111, switch 211, or switch 311, and the DC-DC converter unit is bypassed and does not work.

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

[0056] More specifically, for Figure 1 and Figure 3 In the embodiments described, the CUK converter topology or Buck-Boost converter topology can be controlled by an outer loop of output voltage and an inner loop of inductor current; in addition, sampling the inductor current can also be used for overcurrent protection.

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

[0058] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A battery boosting circuit, characterized in that, The device includes a DC-DC converter, a first capacitor, and a first switch. The input terminal of the DC-DC converter is connected in parallel with the battery, and the output terminal of the DC-DC converter 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. The first switch is a bidirectional switch. When the battery voltage is not lower than a voltage set value, the first switch is closed, and the DC-DC converter is bypassed and does not work. When the battery voltage is lower than the voltage set value, the first switch is turned off, and the DC-DC converter works. The drive signal of the switch in the DC-DC converter is adjusted so that the output voltage of the DC-DC converter is equal to the voltage set value minus the battery voltage.

2. The battery boosting circuit as described in claim 1, characterized in that, The DC-DC converter unit is a non-isolated DC-DC converter topology, and the first capacitor is connected in series with the negative terminal of the battery.

3. The battery boosting circuit as described in claim 2, characterized in that, The DC-DC converter unit adopts the CUK converter topology.

4. The battery boosting circuit as described in claim 2, characterized in that, The DC-DC converter unit adopts a Buck-Boost converter topology.

5. The battery boosting circuit as described in claim 1, characterized in that, The DC-DC converter unit is an isolated DC-DC converter topology, and the first capacitor is connected in series with the positive terminal of the battery.

6. The battery boosting circuit as described in claim 5, characterized in that, The DC-DC conversion unit includes an inverter module, a resonant module, a transformer module, and a rectifier module. The battery, the inverter module, the resonant module, the transformer module, the rectifier module, and the first capacitor are connected in parallel in sequence.

7. The battery boosting circuit as described in claim 1, characterized in that, The bidirectional switch comprises two switches connected in reverse series.

8. A battery boosting method, characterized in that, Applied to a battery boosting circuit as described in any one of claims 1-7, comprising, Step S1: Sample the battery voltage and the output voltage of the DC-DC converter unit; Step S2: When the battery voltage is not lower than the voltage setting value, the first switch is closed, and the DC-DC converter 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 converter unit operates, and the drive signal of the switch in the DC-DC converter unit is adjusted so that the output voltage of the DC-DC converter unit is equal to the voltage setting value minus the battery voltage.

9. An electric bicycle, characterized in that, The battery boosting circuit includes any one of claims 1-7, further comprising a motor controller and a battery, wherein the input terminal of the battery boosting circuit is connected in parallel with the battery, the output terminal of the battery boosting circuit is connected in series with the battery, and the two ends of the series connection between the output terminal of the battery boosting circuit and the battery are connected in parallel with the motor controller.

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