Battery management circuit based on bidirectional DC-DC converter
By using a battery management circuit based on a bidirectional DC-DC converter and employing synchronous rectification and differential acquisition techniques, the switching losses and voltage and current oscillations of the dual-transistor Buck-Boost converter during high-frequency operation are solved, thereby improving the anti-interference capability and measurement accuracy of the battery management circuit.
Patent Information
- Application Number
- CN202422458186.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-11
- Publication Date
- 2025-10-28
- Estimated Expiration
- 2034-10-11
AI Technical Summary
Existing dual-transistor Buck-Boost converters suffer from high switching losses and severe voltage and current oscillations when operating at high frequencies, which affect the voltage and current stress of the devices and cause interference to the control circuit.
A battery management circuit based on a bidirectional DC-DC converter is adopted, including a power supply regulation unit, a chip, a dual-transistor conversion unit, a voltage acquisition unit, a current acquisition unit, a comparator, and a digital signal unit. Through synchronous rectification and differential acquisition, the anti-interference capability is enhanced, and the measurement accuracy and stability are improved.
It reduces switching losses, lowers voltage and current oscillations, improves the voltage and current stress of the device and the stability of the control circuit, and enhances the anti-interference capability of the battery management circuit.
Smart Images
Figure CN223487876U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of battery management technology, specifically relating to a battery management circuit based on a bidirectional DC-DC converter. Background Technology
[0002] A dual-transistor Buck-Boost converter is a power conversion circuit capable of voltage boosting. Combining the characteristics of buck and boost converters, it provides a stable DC output voltage when the input voltage is higher or lower than the output voltage. To improve the power density of a dual-transistor Buck-Boost converter, the switching frequency needs to be increased to reduce the size and weight of the inductor and capacitor. However, when the switching transistors operate in hard-switching mode, voltage and current overlap during switching, resulting in significant switching losses. The total switching losses increase significantly with increasing switching frequency, making it difficult to guarantee high efficiency at high frequencies. Furthermore, during hard switching, the large voltage and current change rates of the switching transistors cause oscillations in the main power circuit, increasing voltage and current stress on the devices and causing serious interference to control circuits and other electrical equipment. Utility Model Content
[0003] Purpose of the utility model: To provide a battery management circuit based on a bidirectional DC-DC converter, which solves the above-mentioned problems existing in the prior art.
[0004] Technical Solution: A battery management circuit based on a bidirectional DC-DC converter includes a power supply regulation unit. The input of the power supply regulation unit is connected to an external power source. The output of the power supply regulation unit is simultaneously connected to the power supply input of a chip and the power supply input of a dual-transistor converter. The output of the dual-transistor converter is simultaneously connected to the input of a voltage acquisition unit and a current acquisition unit. The voltage and current values of the dual-transistor converter are obtained through the voltage acquisition unit and the circuit acquisition unit. The outputs of the voltage acquisition unit and the current acquisition unit are simultaneously connected to the input of a comparator. The output of the comparator is connected to a digital signal unit. The output of the chip is connected to the input of the dual-transistor converter. With the cooperation of the chip, the comparator, and the digital signal unit, the dual-transistor converter is synchronously rectified.
[0005] Preferably, it further includes a wake-up unit, the output of which is connected to the input of the chip. The wake-up unit includes at least charging wake-up, 485 wake-up, and RTC wake-up, which are connected in parallel between the external power supply and the chip.
[0006] Preferably, the dual-transistor conversion unit includes switching transistors Q1, Q2, Q3, and Q4, diodes D1, D2, D3, and D4, and capacitors C1, C2, C3, C4, and C6. f Resistance R Ld and inductor L C The diode D1 and capacitor C1 are connected in parallel. The cathode of diode D1 is connected to the collector of switching transistor Q1, and the anode of diode D1 is connected to both the emitter of switching transistor Q1 and inductor L. C One end of the diode is connected to the collector of the switching transistor Q2 and the cathode of the diode D2. The diode D2 and the capacitor C2 are connected in parallel. The cathode of the diode D2 is connected to the collector of the switching transistor Q2, and the anode of the diode D2 is connected to the emitter of the switching transistor Q2, the emitter of the switching transistor Q4, and the capacitor C2. f one end and resistor R Ld One end of the inductor L C The other end is connected to both the collector of switching transistor Q4 and the emitter of switching transistor Q3. Diode D3 and capacitor C3 are connected in parallel. The cathode of diode D3 is connected to the collector of switching transistor Q3, and the anode of diode D3 is connected to the emitter of switching transistor Q3. Diode D4 and capacitor C4 are connected in parallel. The anode of diode D4 is connected to the emitter of switching transistor Q4, and the cathode of diode D4 is connected to the collector of switching transistor Q4. f The other end is connected to both the collector of the switching transistor Q3 and the resistor R. Ld The other end.
[0007] Preferably, the power supply regulation unit includes a linear regulator LDO1, a linear regulator LDO2, a synchronous buck regulator 1, and a synchronous buck regulator 2. The synchronous buck regulator 1, the synchronous buck regulator 2, and the linear regulator LDO2 are connected in series. One end of the linear regulator LDO1 is connected to one end of the synchronous buck regulator 1, and the other end of the linear regulator LDO1 is connected to the linear regulator LDO2 through a switch.
[0008] Preferably, synchronous buck regulator 1 is a SY8502 model synchronous buck regulator, and synchronous buck regulator 2 is an H6900 model synchronous buck regulator.
[0009] Preferably, the chip used is the SH367309 model.
[0010] Beneficial effects: This utility model relates to a battery management circuit based on a bidirectional DC-DC converter. The output terminal of the dual-transistor converter single loop is simultaneously connected to a voltage acquisition unit and a current acquisition unit. Both the voltage acquisition unit and the current acquisition unit adopt differential acquisition. Both the voltage acquisition unit and the current acquisition unit have strong anti-interference capabilities, which enhances the anti-interference capability of the dual-transistor converter unit and improves the accuracy and stability of the measurement. Attached Figure Description
[0011] Figure 1 This is a circuit diagram of the dual-transistor converter unit of this utility model;
[0012] Figure 2 This is the Boost mode of the dual-transistor converter unit of this utility model;
[0013] Figure 3 This is the Buck mode of the dual-transistor converter unit of this utility model;
[0014] Figure 4 This is a circuit diagram of the voltage acquisition unit of this utility model;
[0015] Figure 5 This is a circuit diagram of the current acquisition unit of this utility model;
[0016] Figure 6 This is a rectifier circuit diagram of the present invention;
[0017] Figure 7 This is a system block diagram of the power supply regulation unit of this utility model;
[0018] Figure 8 This is the 485 wake-up circuit diagram of this utility model;
[0019] Figure 9 This is the RTC wake-up circuit diagram of this utility model. Detailed Implementation
[0020] like Figures 1 to 9As shown, this utility model provides a technical solution: a battery management circuit based on a bidirectional DC-DC converter, including a power supply regulation unit, a chip, a dual-transistor conversion unit, a voltage acquisition unit, a current acquisition unit, a comparator, a digital signal unit, and a wake-up unit. The chip used is an SH367309 model. The input terminal of the power supply regulation unit is connected to an external power supply, and the output terminal of the power supply regulation unit is simultaneously connected to the power supply input terminal of the chip and the power supply input terminal of the dual-transistor conversion unit. The output terminal of the wake-up unit is connected to the input terminal of the chip, and the output terminal of the dual-transistor conversion unit is simultaneously connected to the input terminals of the voltage acquisition unit and the current acquisition unit. The circuit is accessed through the voltage acquisition unit and the circuit acquisition unit. The voltage and current values of the dual-transistor converter are acquired. The outputs of the voltage acquisition unit and the current acquisition unit are simultaneously connected to the input of a comparator. The output of the comparator is connected to a digital signal unit. The output of the chip is connected to the input of the dual-transistor converter. With the cooperation of the chip, comparator, and digital signal unit, the dual-transistor converter is synchronously rectified. At the same time, the output of the single loop of the dual-transistor converter is simultaneously connected to the voltage acquisition unit and the current acquisition unit. Both the voltage acquisition unit and the current acquisition unit adopt differential acquisition. The voltage acquisition unit and the current acquisition unit have strong anti-interference capabilities, which enhances the anti-interference capability of the dual-transistor converter and improves the accuracy and stability of the measurement.
[0021] In a further embodiment, the wake-up unit includes at least charging wake-up, 485 wake-up, and RTC wake-up, which are connected in parallel between the external power supply and the chip. The circuit diagram for the 485 wake-up is shown below. Figure 8 As shown, when there is communication on the RS485WKEN1 bus, optocoupler U5 operates, and pin 3 of U5 outputs a high level, which is sent to the chip's wake-up interface to complete the chip's wake-up. The circuit diagram for the RTC wake-up is shown below. Figure 9 As shown, the system is set to wake up at a predetermined time via RTC wake-up to check the battery status.
[0022] In a further embodiment, such as Figures 1 to 3 As shown, the dual-transistor conversion unit includes switching transistors Q1, Q2, Q3, and Q4, diodes D1, D2, D3, and D4, and capacitors C1, C2, C3, C4, and C6. f Resistance R Ld and inductor L C The diode D1 and capacitor C1 are connected in parallel. The cathode of diode D1 is connected to the collector of switching transistor Q1, and the anode of diode D1 is connected to both the emitter of switching transistor Q1 and inductor L. COne end of the diode is connected to the collector of the switching transistor Q2 and the cathode of the diode D2. The diode D2 and the capacitor C2 are connected in parallel. The cathode of the diode D2 is connected to the collector of the switching transistor Q2, and the anode of the diode D2 is connected to the emitter of the switching transistor Q2, the emitter of the switching transistor Q4, and the capacitor C2. f one end and resistor R Ld One end of the inductor L C The other end is connected to both the collector of switching transistor Q4 and the emitter of switching transistor Q3. Diode D3 and capacitor C3 are connected in parallel. The cathode of diode D3 is connected to the collector of switching transistor Q3, and the anode of diode D3 is connected to the emitter of switching transistor Q3. Diode D4 and capacitor C4 are connected in parallel. The anode of diode D4 is connected to the emitter of switching transistor Q4, and the cathode of diode D4 is connected to the collector of switching transistor Q4. f The other end is connected to both the collector of the switching transistor Q3 and the resistor R. Ld At the other end, when the input voltage is lower than the output voltage, Q1 is normally open and Q2 is normally off. The two-transistor converter unit is equivalent to a Boost converter, operating in Boost mode, such as... Figure 2 As shown, when the input voltage is higher than the output voltage, Q3 is normally open and Q4 is normally off. The two-transistor converter unit is equivalent to a Buck converter, operating in Buck mode, as follows. Figure 2 and 3 As shown, where Figure 2 It's Boost mode. Figure 3 It's Buck mode.
[0023] In a further embodiment, such as Figure 7 As shown, the power supply regulation unit includes a linear regulator LDO1, a linear regulator LDO2, a synchronous buck regulator 1, and a synchronous buck regulator 2. Synchronous buck regulator 1 is a SY8502 model, and synchronous buck regulator 2 is an H6900 model. The synchronous buck regulator 1, synchronous buck regulator 2, and linear regulator LDO2 are connected in series. One end of the linear regulator LDO1 is connected to one end of the synchronous buck regulator 1, and the other end of the linear regulator LDO1 is connected to the linear regulator LDO2 via a switch. When the input is 48V, the linear regulator LDO1 can provide 0.6A of rated current. For low-power standby, the linear regulator LDO1 is turned off, and the linear regulator LDO2 is turned on. At this time, the system power consumption is <120uA. When the system is off, the input current is approximately 10uA.
[0024] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and all such equivalent transformations fall within the protection scope of the present invention.
Claims
1. A battery management circuit based on a bidirectional DC-DC converter, characterized in that, The system includes a power supply regulation unit, whose input is connected to an external power source. Its output is connected to both the power supply input of a chip and the power supply input of a dual-transistor converter. The output of the dual-transistor converter is connected to both the input of a voltage acquisition unit and the input of a current acquisition unit. The voltage and current values of the dual-transistor converter are acquired through the voltage acquisition unit and the circuit acquisition unit. The outputs of the voltage and current acquisition units are connected to the input of a comparator. The output of the comparator is connected to a digital signal unit. The output of the chip is connected to the input of the dual-transistor converter. With the cooperation of the chip, the comparator, and the digital signal unit, the dual-transistor converter is synchronously rectified.
2. The battery management circuit based on a bidirectional DC-DC converter according to claim 1, characterized in that, It also includes a wake-up unit, the output of which is connected to the input of the chip. The wake-up unit includes at least charging wake-up, 485 wake-up and RTC wake-up, which are connected in parallel between the external power supply and the chip.
3. The battery management circuit based on a bidirectional DC-DC converter according to claim 1, characterized in that, The dual-transistor conversion unit includes switching transistors Q1, Q2, Q3, and Q4, diodes D1, D2, D3, and D4, and capacitors C1, C2, C3, C4, and C6. f Resistance R Ld and inductor L C The diode D1 and capacitor C1 are connected in parallel. The cathode of diode D1 is connected to the collector of switching transistor Q1, and the anode of diode D1 is connected to both the emitter of switching transistor Q1 and inductor L. C One end of the diode is connected to the collector of the switching transistor Q2 and the cathode of the diode D2. The diode D2 and the capacitor C2 are connected in parallel. The cathode of the diode D2 is connected to the collector of the switching transistor Q2, and the anode of the diode D2 is connected to the emitter of the switching transistor Q2, the emitter of the switching transistor Q4, and the capacitor C2. f one end and resistor R Ld One end of the inductor L C The other end is connected to both the collector of switching transistor Q4 and the emitter of switching transistor Q3. Diode D3 and capacitor C3 are connected in parallel. The cathode of diode D3 is connected to the collector of switching transistor Q3, and the anode of diode D3 is connected to the emitter of switching transistor Q3. Diode D4 and capacitor C4 are connected in parallel. The anode of diode D4 is connected to the emitter of switching transistor Q4, and the cathode of diode D4 is connected to the collector of switching transistor Q4. f The other end is connected to both the collector of the switching transistor Q3 and the resistor R. Ld The other end.
4. The battery management circuit based on a bidirectional DC-DC converter according to claim 1, characterized in that, The power supply regulation unit includes a linear regulator LDO1, a linear regulator LDO2, a synchronous buck regulator 1, and a synchronous buck regulator 2. The synchronous buck regulator 1, the synchronous buck regulator 2, and the linear regulator LDO2 are connected in series. One end of the linear regulator LDO1 is connected to one end of the synchronous buck regulator 1, and the other end of the linear regulator LDO1 is connected to the linear regulator LDO2 through a switch.
5. The battery management circuit based on a bidirectional DC-DC converter according to claim 4, characterized in that, Synchronous buck regulator 1 is a SY8502 model synchronous buck regulator, and synchronous buck regulator 2 is an H6900 model synchronous buck regulator.
6. The battery management circuit based on a bidirectional DC-DC converter according to claim 1, characterized in that, The chip used is the SH367309 model.