Low-loss conversion circuit and energy storage system

Abstract

The application relates to a low-loss conversion circuit and an energy storage system. The application comprises a voltage reduction module connected with a power supply, a bypass module connected with the voltage reduction module in parallel, an adjusting module and a control module; the adjusting module is used for detecting an input voltage of the power supply; a dynamic adjusting signal is output to a feedback pin of the control module based on the input voltage, and a first control signal is output to the bypass module when the input voltage is greater than or equal to a reference voltage; a second control signal is output to the bypass module when the input voltage is less than the reference voltage; the bypass module is used for working under the action of the second control signal to bypass the voltage reduction module and stopping working under the action of the first control signal; the control module is used for adjusting a duty cycle of a first driving signal output to the voltage reduction module to be in a preset range based on the dynamic adjusting signal; and the voltage reduction module is used for outputting a power supply voltage after performing voltage reduction processing on the input voltage based on the first driving signal. The method can improve the battery power utilization rate.

Description

Technical Field

[0001] This application relates to the field of energy storage power technology, and in particular to a low-loss conversion circuit and energy storage system. Background Technology

[0002] Currently, for energy storage power supplies with a wide input voltage range, such as 24V-43V, in order to meet the requirements of control modules for DC output functions such as USB-C (Universal Serial Bus - Type C), USB-A (Universal Serial Bus - Type A), and cigarette lighters with a maximum withstand voltage of 40V, a BUCK circuit (Buck Switching Regulator Circuit) is added between the battery and these DC output functions. The output voltage of this BUCK circuit is fixed, such as 22V.

[0003] However, in this BUCK circuit, when the input voltage is high (e.g., 43V), the current through the first diode generates significant losses; when the input voltage is low (24-29V), although theoretically the battery can directly power the circuit to avoid the voltage drop losses of the BUCK circuit, the traditional operating method cannot avoid these unnecessary losses, resulting in significant or unnecessary losses in the energy storage power supply in this BUCK circuit section, reducing the battery power utilization rate. Summary of the Invention

[0004] Therefore, it is necessary to provide a low-loss conversion circuit and energy storage system to address the aforementioned technical problems.

[0005] In a first aspect, this application provides a low-loss conversion circuit, comprising:

[0006] A step-down module connected to a power supply, a bypass module connected in parallel with the step-down module, an adjustment module, and a control module;

[0007] The adjustment module is used to detect the input voltage of the power supply; output a dynamic adjustment signal to the feedback pin of the control module based on the input voltage; and output a first control signal to the bypass module when the input voltage is greater than or equal to the reference voltage; and output a second control signal to the bypass module when the input voltage is less than the reference voltage.

[0008] The bypass module is configured to operate under the action of the second control signal to bypass the buck module; and to stop operating under the action of the first control signal.

[0009] The control module is used to adjust the duty cycle of the first drive signal output to the buck module to a preset range based on the dynamic adjustment signal;

[0010] The step-down module is used to step down the input voltage based on the first drive signal and then output the supply voltage.

[0011] In one embodiment, the bypass module includes: a switching unit and a driver;

[0012] The first end of the switching unit is connected to the power supply, the second end of the switching unit is connected to the output end of the circuit, and the control end of the switching unit is connected to the output end of the driver.

[0013] The driver has its input terminal connected to the adjustment module and its output terminal connected to the control terminal of the switching unit.

[0014] The switching unit is used to turn on under the action of the second control signal and turn off under the action of the first control signal.

[0015] In one embodiment, the adjustment module is further configured to output a first enable signal to the enable terminal of the control module when the input voltage is greater than or equal to the reference voltage, so that the control module adjusts the duty cycle of the first drive signal output to the buck module to be within a preset range based on the dynamic adjustment signal; and to output a second enable signal to the enable terminal of the control module when the input voltage is less than the reference voltage, so that the control module stops working.

[0016] In one embodiment, the adjustment module includes:

[0017] A voltage sampling unit is used to acquire the input voltage;

[0018] The comparison unit is configured to output the second control signal when the input voltage is less than the reference voltage, and to output the first control signal when the input voltage is greater than or equal to the reference voltage;

[0019] A feedback adjustment unit is used to output the dynamic adjustment signal to the feedback pin of the control module based on the input voltage.

[0020] In one embodiment, the voltage sampling unit includes: a fifth resistor, a seventh resistor, and a voltage follower;

[0021] The first end of the fifth resistor is connected to the power supply, the second end of the fifth resistor is connected to the first end of the seventh resistor and the non-inverting input of the voltage follower, the second end of the seventh resistor is grounded, and the inverting input of the voltage follower is connected to the output of the voltage follower.

[0022] In one embodiment, the second control signal is a high-level signal, the first control signal is a low-level signal, and the comparison unit includes:

[0023] The comparator has its inverting input connected to the voltage sampling unit, its non-inverting input connected to the reference power supply, and its output connected to the bypass module. The comparator outputs a high-level signal when the input voltage is less than the reference voltage and outputs a low-level signal when the input voltage is greater than or equal to the reference voltage.

[0024] In one embodiment, the feedback adjustment unit includes an enable control subunit and an adjustable voltage divider unit, wherein the input terminal of the enable control subunit is connected to the output terminal of the comparator unit, and the input terminal of the adjustable voltage divider unit is connected to the voltage sampling unit.

[0025] The enable control subunit is used to output a first enable signal to the enable pin of the control module under the action of the first control signal, and to output a second enable signal to the enable pin of the control module under the action of the second control signal.

[0026] The adjustable resistance value of the adjustable voltage divider unit decreases as the input voltage increases. The adjustable voltage divider unit is used to divide the input voltage using the adjustable resistance value to obtain the dynamic adjustment signal.

[0027] In one embodiment, the adjustable voltage divider unit includes: a transistor, the base of which is connected to the voltage sampling unit, and the emitter of which is grounded;

[0028] The transistor is used to operate in the amplification region when the input voltage is greater than or equal to the reference voltage, and the equivalent resistance between the collector and emitter of the transistor decreases as the input voltage increases.

[0029] In one embodiment, the adjustable voltage divider unit further includes:

[0030] The sixth resistor, the first resistor, the second resistor, and the third resistor;

[0031] The base of the transistor is connected to the voltage sampling unit through the sixth resistor. The collector of the transistor is connected to the first end of the second resistor. The second end of the second resistor is connected to the first end of the first resistor, the first end of the third resistor, and the feedback pin of the control module. The second end of the third resistor is grounded. The second end of the first resistor is connected to the circuit output terminal.

[0032] In one embodiment, the control module is configured to adjust the duty cycle of the first drive signal output to the buck module to be within the preset range when the voltage of the dynamic adjustment signal is less than a preset value.

[0033] Secondly, this application also provides an energy storage system, which includes a low-loss conversion circuit as described in the first aspect, wherein the circuit output terminal of the low-loss conversion circuit is connected to a plurality of DC output interfaces of the energy storage system.

[0034] The aforementioned low-loss conversion circuit and energy storage system include: a step-down module connected to a power supply, a bypass module connected in parallel with the step-down module, an adjustment module, and a control module; the adjustment module is used to detect the input voltage of the power supply; output a dynamic adjustment signal to the feedback pin of the control module based on the input voltage, and output a first control signal to the bypass module when the input voltage is greater than or equal to a reference voltage; output a second control signal to the bypass module when the input voltage is less than the reference voltage; the bypass module is used to operate under the action of the second control signal to bypass the step-down module; and stop operating under the action of the first control signal; the control module is used to adjust the duty cycle of the first drive signal output to the step-down module to a preset range based on the dynamic adjustment signal; the step-down module is used to output a supply voltage after stepping down the input voltage based on the first drive signal. This scheme allows the bypass module to operate directly by bypassing the buck module when the input voltage is lower than the reference voltage. This eliminates the need for the battery energy to be stepped down by the BUCK circuit, avoiding unnecessary losses in the BUCK circuit at low input voltages, as is common in traditional schemes. When the input voltage is greater than or equal to the reference voltage, the bypass module stops operating. The control module then dynamically adjusts the duty cycle of the first drive signal output to the buck module within a preset range. This allows the buck module to efficiently step down the input voltage to the target value under the influence of the first drive signal. Compared to the fixed duty cycle in traditional schemes, which results in significant losses, dynamically optimizing the duty cycle significantly reduces energy loss at high input voltages. Furthermore, the mechanism of the adjustment module real-time monitoring of the input voltage and feedback of the dynamic adjustment signal ensures that the buck module always operates within its efficient range, further improving the overall system's energy conversion efficiency over a wide input voltage range. This effectively increases battery power utilization and avoids the technical drawbacks of high and unnecessary losses coexisting. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of a circuit that uses a BUCK circuit for voltage reduction in related technologies.

[0037] Figure 2 A schematic diagram of a low-loss conversion circuit in one embodiment. Figure 1 ;

[0038] Figure 3 This is a schematic diagram of the bypass module 22 and the buck module 21 in a low-loss conversion circuit in one embodiment;

[0039] Figure 4 A schematic diagram of a low-loss conversion circuit in one embodiment. Figure 2 ;

[0040] Figure 5 This is a schematic diagram of the control module 24 and the adjustment module 23 in a low-loss conversion circuit in one embodiment. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0042] In energy storage power supplies with a wide battery voltage range (24V - 43V), for cost reasons, control chips with a maximum withstand voltage of 40V are used for DC output functions such as USB-C, USB-A, and cigarette lighter. To meet the withstand voltage requirements of the control chip, a BUCK circuit needs to be added between the battery output terminal and these DC output function modules to regulate the output voltage to below 40V.

[0043] For example, Figure 1 This is a schematic diagram of a circuit using a BUCK circuit for voltage reduction in related technologies. For example... Figure 1As shown, the BUCK circuit includes: a driver, a first MOS (Metal-Oxide-Semiconductor Field-Effect Transistor) Q1, a first diode D1, a first inductor LD1, capacitors C1 and C2. It can be seen that this BUCK circuit is connected between the power supply (i.e., the battery) and the output voltage terminal. Typically, the supply voltage Vout of the BUCK circuit is a fixed value (e.g., 22V). Under different battery voltages BAT+, the power conversion efficiency will experience varying degrees of loss. When the battery voltage BAT+ is high (e.g., 43V), the duty cycle of the BUCK circuit is approximately 51%. This means that current will flow through the first diode D1 for 49% of the cycle time. Especially when the downstream DC output functions such as USB-C, USB-A, and cigarette lighter are operating at full load, the current in the first diode D1 is large, resulting in significant losses.

[0044] When the battery voltage BAT+ is low (e.g., 24-29V), the duty cycle exceeds 75%, meaning that less than 25% of the cycle time current flows through the first diode D1. Taking a battery voltage of 24V as an example, the duty cycle is as high as 91.7%, meaning that 8.3% of the cycle time current flows through the first diode D1. In fact, within the 24V-29V voltage range, the battery voltage BAT+ already meets the voltage withstand requirements of the control chip. The battery voltage could directly power the downstream DC output circuits such as USB-C, USB-A, and cigarette lighter via the constantly conducting first MOSFET Q1, without needing to pass through the BUCK circuit for voltage reduction. This would avoid the losses generated by the first diode D1. However, the traditional operating mode cannot achieve this optimization, making these losses unavoidable.

[0045] In summary, traditional operating methods result in significant or unnecessary losses in certain battery voltage ranges of the energy storage power supply during the BUCK circuit, reducing battery power utilization and weakening the product's market competitiveness.

[0046] This application provides a low-loss conversion circuit and energy storage system, which improves the energy conversion efficiency of the entire system over a wide input voltage range, effectively improves battery power utilization, and avoids the problem of high loss and unnecessary loss coexisting.

[0047] In one exemplary embodiment, such as Figure 2 As shown, a schematic diagram of a low-loss conversion circuit is provided in one embodiment. Figure 1 The circuit includes:

[0048] The power supply includes a step-down module 21 connected to a power source, a bypass module 22 connected in parallel with the step-down module 21, an adjustment module 23, and a control module 24; wherein the power source can be a battery, and the battery can output a battery voltage BAT+.

[0049] The adjustment module 23 is used to detect the input voltage of the power supply; based on the input voltage, it outputs a dynamic adjustment signal to the feedback pin FB of the control module 24, and outputs a first control signal to the bypass module 22 when the input voltage is greater than or equal to the reference voltage; and outputs a second control signal to the bypass module 22 when the input voltage is less than the reference voltage.

[0050] The bypass module 22 is used to bypass the step-down module 21 under the action of the second control signal, and to stop working under the action of the first control signal.

[0051] The control module 24 is used to adjust the duty cycle of the first drive signal output to the step-down module 21 to a preset range based on the dynamic adjustment signal.

[0052] The step-down module 21 is used to step down the input voltage based on the first drive signal and output the supply voltage Vout.

[0053] The aforementioned duty cycle being within the preset range refers to a duty cycle of 81.4% ± 5%. Figure 2 In this context, GND represents the ground terminal.

[0054] In some embodiments, the reference voltage can be 30V. The input voltage being greater than or equal to the reference voltage can mean that BAT+ is in the range of 30V-43V, and the input voltage being less than the reference voltage means that BAT+ is less than 30V.

[0055] In some embodiments, the control module 24 described above may be a control chip (Control IC).

[0056] In some embodiments, the first control signal can be a low-level signal, and the second control signal can be a high-level signal. That is, Figure 2 In the circuit, the adjustment module 23 can output a first control signal to the bypass module 22 when the input voltage is greater than or equal to the reference voltage, so as to control the bypass module 22 to not work, and output a dynamic adjustment signal to the feedback pin FB of the control module 24 based on the input voltage, so that the control module 24 adjusts the duty cycle of the first drive signal output to the buck module 21 to a preset range based on the dynamic adjustment signal, so that the buck module 21 can output the corresponding supply voltage Vout under the action of the first drive signal; when the input voltage is less than the reference voltage, it outputs a second control signal to the bypass module 22 to control the bypass module 22 to work and bypass the buck module 21.

[0057] The aforementioned dynamic adjustment signal can be an analog voltage signal that is positively correlated with the input voltage change or a pulse width modulation (PWM) signal.

[0058] When the input voltage is less than the reference voltage (e.g., 30V), there is still a certain distance between the input voltage and the withstand voltage value of the control module 24 (e.g., 40V). At this time, direct power supply will not exceed the withstand voltage value, so there is no need to let the buck module 21 consume power. Therefore, a second control signal is output to the bypass module 22 to control the bypass module 22 to work and bypass the buck module 21, which can avoid the buck module 21 consuming power.

[0059] When the input voltage is greater than or equal to the reference voltage (e.g., 30V), the voltage approaches the critical value of the 40V withstand voltage (e.g., 40V), at which point voltage reduction is required. At this time, a first control signal is output to the bypass module 22 to disable it and allow the buck module 21 to operate. Simultaneously, the buck module 21 performs voltage reduction under the action of a first drive signal with a duty cycle within a preset range. This allows for a significant reduction in energy loss at high input voltages through dynamic optimization of the duty cycle.

[0060] In the above embodiments, when the input voltage is less than the reference voltage, the adjustment module controls the bypass module to operate, directly bypassing the buck module. This allows battery energy to be output directly without passing through the BUCK circuit, avoiding unnecessary losses in the BUCK circuit at low input voltages in traditional solutions. When the input voltage is greater than or equal to the reference voltage, the bypass module stops operating. The control module can adjust the duty cycle of the first drive signal output to the buck module within a preset range based on the dynamic adjustment drive signal. Under the action of this first drive signal, the buck module can efficiently reduce the input voltage to the target value. Compared to the fixed duty cycle in traditional solutions, which leads to significant losses, dynamically optimizing the duty cycle significantly reduces energy loss at high input voltages. Furthermore, the mechanism of the adjustment module real-time detection of the input voltage and feedback of the dynamic adjustment signal ensures that the buck module always operates within the high-efficiency range, further improving the energy conversion efficiency of the entire system over a wide input voltage range, effectively increasing battery power utilization, and avoiding the technical defects of high and unnecessary losses coexisting.

[0061] In some embodiments, such as Figure 2As shown, the above-mentioned adjustment module 23 is also used to output a first enable signal to the enable terminal EN (also called the enable pin) of the control module 24 when the input voltage is greater than or equal to the reference voltage, so that the control module 24 adjusts the duty cycle of the first drive signal output to the buck module 21 to be within a preset range based on the dynamic adjustment signal; and outputs a second enable signal to the enable terminal EN of the control module 24 when the input voltage is less than the reference voltage, so that the control module 24 stops working.

[0062] In the above embodiments, when the input voltage is greater than or equal to the reference voltage, the adjustment module sends a first enable signal to the enable terminal of the control module to wake up the control module. At this time, the control module optimizes the duty cycle of the drive signal in real time based on the dynamic adjustment signal (e.g., 81.4% ± 5%), enabling the buck module to efficiently reduce voltage in the high voltage range and avoiding the large current loss of the freewheeling diode under the traditional fixed duty cycle. When the input voltage is less than the reference voltage, the adjustment module outputs a second enable signal, forcing the control module to stop working and cutting off its own power consumption. In conjunction with the bypass module being turned on, the buck module is bypassed, achieving dual energy saving. This avoids the conversion loss of the buck circuit and eliminates the no-load power consumption of the control module, further reducing unnecessary losses compared to the continuous operation mode of the control module in the traditional solution. This mechanism allows the system to always maintain a state of high efficiency when working and sleep when idle within a wide voltage range, reducing energy loss and significantly improving battery power utilization.

[0063] In one exemplary embodiment, in Figure 2 On the basis of, such as Figure 3 As shown, a schematic diagram of the bypass module 22 and the buck module 21 in a low-loss conversion circuit is provided in one embodiment.

[0064] like Figure 3 As shown, the bypass module 22 includes: a switching unit 221 and a second driver 222; the first terminal of the switching unit 221 is connected to the power supply, the second terminal of the switching unit 221 is connected to the circuit output terminal, which can output the supply voltage Vout, and the control terminal of the switching unit 221 is connected to the output terminal of the second driver 222; the input terminal of the second driver 222 is connected to... Figure 2 The output terminal of the adjustment module 23 and the second driver 222 are connected to the control terminal of the switch unit 221; the switch unit 221 is used to turn on under the action of the second control signal and turn off under the action of the first control signal.

[0065] Specifically, the aforementioned switching unit 221 can be a second MOSFET Q2. The first terminal of the second MOSFET Q2 (i.e. Figure 3 Pin 3 of the second MOSFET Q2 is connected to the power supply, and the second terminal of the second MOSFET Q2 (i.e., Figure 3 Pin 2 of the second MOSFET Q2 is connected to the circuit output terminal, and the control terminal of the second MOSFET Q2 is connected to the circuit output terminal. Figure 3 Pin 1 of Q2 is connected to the output of the second driver 222. Figure 3 Drv2 in the input is the drive signal to the second driver 222.

[0066] For example, such as Figure 3 As shown, the step-down module 21 includes: a first driver 211, a third MOSFET Q3, a second diode D2, a second inductor LD2, a third capacitor C3, and a fourth capacitor C4. Figure 3 Drv1 in the input is the drive signal to the first driver 211.

[0067] Based on the above Figure 3 In the circuit shown, in the bypass module 22, when the input voltage (such as battery voltage BAT+) is less than the reference voltage (such as 30V), the regulating module 23 outputs a second control signal (high-level signal) to the second driver 222, driving Q2 to turn on. At this time, the power supply is directly connected to the circuit output terminal, and the buck module 21 is bypassed to avoid its power consumption. When the input voltage is greater than or equal to the reference voltage, the regulating module 23 outputs a first control signal (low-level signal), controlling Q2 to turn off, the bypass module 22 stops working, and the buck module 21 runs.

[0068] Based on the above Figure 3 The circuit shown has Drv1 input to the first driver 211, adjusting the switching duty cycle of Q3 (preset 81.4%±5%). When Drv1 is high, Q3 is turned on, and the power supply charges LD2 through Q3, storing energy in LD2. When Drv1 is low, Q3 is turned off, and the inductor supplies power to the load through D2 freewheeling. At the same time, C3 and C4 filter and stabilize the output supply voltage Vout. Figure 2 The control module 24 optimizes the duty cycle in real time based on the signal fed back by the adjustment module 23 to ensure efficient voltage reduction and reduce energy loss when the input voltage is high.

[0069] In one exemplary embodiment, in Figure 2 On the basis of, such as Figure 4 The diagram shown is a schematic of a low-loss conversion circuit in one embodiment. Figure 2 .like Figure 4 As shown, the adjustment module 23 includes: a voltage sampling unit 231 for acquiring the input voltage; a comparison unit 232 for outputting a second control signal when the input voltage is less than the reference voltage and outputting a first control signal when the input voltage is greater than or equal to the reference voltage; and a feedback adjustment unit 233 for outputting a dynamic adjustment signal to the feedback pin FB of the control module 24 based on the input voltage.

[0070] In one exemplary embodiment, in Figure 4On the basis of, such as Figure 5 The diagram shown is a schematic of the control module 24 and the adjustment module 23 in a low-loss conversion circuit in one embodiment.

[0071] For example, such as Figure 5 As shown, the control module 24 is Figure 5 The control chip (Control IC) in the middle.

[0072] For example, such as Figure 5 As shown, Figure 4 The voltage sampling unit 231 within the adjustment module 23 may include: a fifth resistor R5, a seventh resistor R7, and a voltage follower U1A; the first terminal of the fifth resistor R5 is connected to the power supply, and the second terminal of the fifth resistor is connected to the first terminal of the seventh resistor R7 and the non-inverting input terminal of the voltage follower U1A (i.e., Figure 5 Pin 5 of U1A), the second terminal of the seventh resistor R7 is grounded, and the inverting input terminal of the voltage follower U1A (i.e., Figure 5 Pin 4 of U1A is connected to the output of voltage follower U1A (i.e., Figure 5 Pin 2 of U1A).

[0073] For example, such as Figure 5 As shown, the second control signal is a high-level signal, and the first control signal is a low-level signal. The comparison unit 232 in the adjustment module 23 includes: a comparator U2A, and the inverting input terminal of the comparator U2A (i.e., Figure 5 Pin 4 of comparator U2A is connected to voltage sampling unit 231, and the non-inverting input of comparator U2A (i.e., Figure 5 Pin 5 of comparator U2A is connected to a reference power supply, which outputs a reference voltage Vref. The output of comparator U2A (i.e., Figure 5 Pin 2 of U2A is connected to bypass module 22. Comparator U2A is used to output a high-level signal when the input voltage is less than the reference voltage and a low-level signal when the input voltage is greater than or equal to the reference voltage.

[0074] For example, such as Figure 5 As shown, the feedback adjustment unit 233 in the adjustment module 23 includes an enable control subunit and an adjustable voltage divider unit. The input terminal of the enable control subunit is connected to the output terminal of the comparator unit U2A, and the input terminal of the adjustable voltage divider unit is connected to the voltage sampling unit 231. The enable control subunit is used to output a first enable signal to the enable pin EN of the control module 24 under the action of the first control signal, and to output a second enable signal to the enable pin EN of the control module 24 under the action of the second control signal.

[0075] For example, such as Figure 5As shown, the above-mentioned enable control subunit includes a fifth MOSFET Q5. The control terminal of the fifth MOSFET Q5 is the input terminal of the enable control subunit. The first terminal of the fifth MOSFET Q5 is connected to the enable pin EN of the control chip, and the second terminal of the fifth MOSFET Q5 is grounded.

[0076] The adjustable voltage divider unit has an adjustable resistance value that decreases as the input voltage increases. The adjustable voltage divider unit is used to divide the input voltage using the adjustable resistance value to obtain a dynamic adjustment signal.

[0077] For example, such as Figure 5 As shown, the adjustable voltage divider unit includes: transistor Q4, the base of transistor Q4 is connected to voltage sampling unit 231, and the emitter of transistor Q4 is grounded, i.e. connected to ground terminal GND.

[0078] Transistor Q4 is used to operate in the amplification region when the input voltage is greater than or equal to the reference voltage. The equivalent resistance between the collector and emitter of transistor Q4 decreases as the input voltage increases.

[0079] In some embodiments, the adjustable voltage divider unit further includes: a sixth resistor R6, a first resistor R1, a second resistor R2, and a third resistor R3; the base of transistor Q4 is connected to voltage sampling unit 231 through the sixth resistor R6, the collector of transistor Q4 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is connected to the first end of the first resistor R1, the first end of the third resistor R3, and the feedback pin FB of control module 24, the second end of the third resistor R3 is grounded, and the second end of the first resistor R1 is connected to the circuit output terminal.

[0080] The aforementioned feedback adjustment unit 233 optimizes the working efficiency of the buck module 21 through a dynamic voltage divider mechanism, significantly reducing energy loss over a wide input voltage range. The adjustable voltage divider characteristic of this unit allows it to adjust the feedback signal of the control module 24 in real time according to the input voltage. Specifically, when the input voltage increases, the equivalent resistance of transistor Q4 decreases, the voltage division ratio decreases, forcing the control module 24 to increase the duty cycle of the first drive signal, ensuring that the buck module 21 can still efficiently convert energy in the high-voltage range. Conversely, when the input voltage decreases, the equivalent resistance increases, the voltage division ratio increases, and the duty cycle of the first drive signal decreases accordingly, avoiding losses caused by excessive voltage reduction. This dynamic adjustment mechanism ensures that the buck module 21 always operates within the optimal duty cycle range, effectively reducing the freewheeling loss of traditional fixed duty cycle designs at high voltage inputs.

[0081] Furthermore, the aforementioned feedback adjustment unit 233 and comparator unit 232 work together to achieve intelligent start-stop control of the control module 24. When the input voltage is lower than the reference voltage, the comparator unit 232 outputs a high-level signal, enabling the control subunit to cut off the power supply to the control module 24. At the same time, the bypass module 22 is turned on, completely eliminating the static power consumption of the buck module 21 and the control module 24. When the input voltage is higher than the reference voltage, the control module 24 is awakened and precisely adjusts the duty cycle of the first drive signal based on the dynamic voltage divider signal. This dual energy-saving strategy not only avoids the conversion loss during the buck process but also eliminates the no-load power consumption of the control module 24, enabling the circuit to achieve optimal energy efficiency across the entire voltage range.

[0082] It should be noted that, as Figure 5 As shown, the circuit also includes: a third diode D3, resistors R9, R11, R8, R10, R4, etc. Figure 5 VCC and Vcc1, as shown, represent different power supply terminals.

[0083] For example, as described above Figure 5 Taking the circuit shown as an example, the resistance value of the sixth resistor R6 should be set so that when the input voltage is in the range of 30V-43V, the transistor Q4 operates in the amplification region. When the transistor Q4 operates in the amplification region, the relationship between the current at its base and collector is Ic = β*Ib.

[0084] Where β is the amplification factor of transistor Q4, Ic is the collector current, and Ib is the base current.

[0085] The resistance value of the second resistor R2 mentioned above needs to be set so that when the input voltage is 43V, the maximum output supply voltage is 35V, and when the input voltage is in the range of 30V-43V, the duty cycle of the first drive signal is controlled at approximately 81.4%. Here, the 81.4% duty cycle of the first drive signal can be understood as a theoretically calculated value. In the actual circuit, the specific output duty cycle will fluctuate within a certain range of 81.4%, and can be determined according to the actual circuit. The 81.4% in this embodiment is only for clearly illustrating the example value shown in the scheme.

[0086] In this embodiment, the relationship between the duty cycle of the first driving signal and the input voltage BAT+ and the output supply voltage Vout can be expressed as: D = Vout / BAT+. The relationship between the duty cycle and the input voltage BAT+ and the output supply voltage Vout is shown in Table 1.

[0087] Table 1

[0088]

[0089] In some embodiments, the control module 24 is configured to output to when the voltage of the dynamic adjustment signal is less than a preset value. Figure 4 The duty cycle of the first drive signal (i.e. Drv1) of the step-down module 21 is adjusted to be within a preset range.

[0090] In some embodiments, the above preset values ​​can be set according to actual needs, and the embodiments of this application are not limited thereto.

[0091] In the above Figure 5 The circuit shown works as follows:

[0092] When BAT+ is in the 30V-43V range, after being divided by R5 and R7, BAT+ enters the non-inverting input of U1A (pin 5 of U1A). The output of U1A (pin 2 of U1A) follows the output voltage VBAT+ from the non-inverting input. Since VBAT+ is greater than the reference voltage Vref, pin 2 of comparator U2A outputs a low-level signal, i.e., Drv2 is a low-level signal. This low-level signal causes... Figure 3 When Q2 is cut off, and Q5 is also cut off, the enable pin EN of the control IC will not be pulled low, and the control IC will continue to work.

[0093] Meanwhile, the output voltage VBAT+ of U1A (i.e., pin 2 of U1A) passes through the third transistor D3 and R6, and then enters Q4, causing Q4 to operate in the amplification region. At this time, R3, R2, and Q4 are connected in parallel and then R1 to divide Vout. The voltage divider then enters the feedback pin FB of the control chip, thereby adjusting the duty cycle of Drv1 to about 81.4% based on BAT+. The corresponding relationship between different BAT+ and Vout voltages is shown in Table 1.

[0094] When Q4 operates in the amplification region, its resistance decreases proportionally with increasing current. For example, a larger BAT+ value results in a smaller internal resistance of Q4, a smaller resistance after R3, R2, and Q4 are connected in parallel, and a smaller percentage of the voltage across the feedback pin FB. Since the feedback value is fixed, when the voltage detected by the feedback pin FB is less than the preset value, the control chip adjusts the duty cycle of Drv1 to increase the output supply voltage Vout. This ensures that when the battery voltage is in the range of 30V-43V, 81.4% of the cycle time is... Figure 3 Q3 conduction time is 18.6%. Figure 3 D2 performs continuous current operation, thus, under the same operating conditions, because Figure 3 The freewheeling time of D2 is significantly reduced, thus reducing losses in this stage of the circuit. Although the on-time of Q3 increases, due to... Figure 3 The internal resistance of Q3 is small, so the loss is still very small.

[0095] For example, with a 2mΩ resistor and a current of 10A, an increase of 30.4% in the on-time results in an increase of 0.06W in power loss. And for... Figure 3 If the on-state voltage drop of D2 is 0.7V, the freewheeling time is reduced by 30.4%, and the power loss is reduced by 2.128W. Therefore, in the example of 10A current operation, the total power loss is reduced by 2.068W.

[0096] It should be noted that the higher the battery voltage BAT+, the larger VBAT+, the larger the current Ib entering the base of Q4, and the larger the collector current Ic. Therefore, the smaller the value of the feedback pin FB of the control chip after R3, R2, and Q4 are connected in parallel and divided by R1 to Vout, the higher the output supply voltage Vout will be due to the internal control principle of the control chip.

[0097] When BAT+ is less than 30V, BAT+ is divided by R5 and R7 and enters the non-inverting input of U1A (pin 5 of U1A). The output of U1A (pin 2 of U1A) follows the output voltage VBAT+ from the non-inverting input. Since VBAT+ is less than the reference voltage Vref, pin 2 of comparator U2A outputs a high level, i.e., Drv2 is a high-level signal. This high-level signal controls... Figure 3 When Q2 is turned on, Q5 is also turned on, pulling the enable pin EN of the control chip low, causing the control chip to stop working, i.e., the BUCK circuit stops working.

[0098] In the example above, BAT+ went through Figure 3 By directly powering Q2, the losses caused by current flowing through the freewheeling diode during low battery voltage operation are avoided, as are the losses generated by the inductor. Similarly, although the on-time of the MOSFET is increased, the overall losses are reduced due to the reduction in losses from the freewheeling diode and inductor.

[0099] In summary, within the full range of battery voltage BAT+ from 24V to 43V, by applying the circuit in the embodiments of this application, the overall loss is reduced to varying degrees under different battery voltages, especially when the back-end is operating at full load, thereby increasing the battery power utilization rate of the energy storage power supply.

[0100] The circuit provided in this application embodiment can not only fix the duty cycle at about 81.4% and operate in a low-loss state when the battery voltage is high, but also avoid the loss generated in the freewheeling diode and the loss generated in the inductor when the battery voltage is low.

[0101] In some embodiments, this application also provides an energy storage system, which includes a low-loss conversion circuit as described in any of the above embodiments, and the circuit output terminal of the low-loss conversion circuit is connected to a plurality of DC output interfaces of the energy storage system.

[0102] The aforementioned DC output interfaces may include, but are not limited to: USB-C, USB-A, cigarette lighter, etc.

[0103] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0104] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A low-loss conversion circuit, characterized in that, include: A step-down module connected to a power supply, a bypass module connected in parallel with the step-down module, an adjustment module, and a control module; The adjustment module is used to detect the input voltage of the power supply; output a dynamic adjustment signal to the feedback pin of the control module based on the input voltage; and output a first control signal to the bypass module when the input voltage is greater than or equal to the reference voltage. When the input voltage is less than the reference voltage, a second control signal is output to the bypass module; The adjustment module includes: a feedback adjustment unit, used to output the dynamic adjustment signal to the feedback pin of the control module based on the input voltage; the feedback adjustment unit includes: an enable control subunit and an adjustable voltage divider unit, the enable control subunit being used to output a first enable signal to the enable pin of the control module under the action of the first control signal, and to output a second enable signal to the enable pin of the control module under the action of the second control signal; the adjustable voltage divider unit has an adjustable resistance value that decreases as the input voltage increases, and is used to divide the input voltage through the adjustable resistance value to obtain the dynamic adjustment signal; the adjustable voltage divider unit includes: a transistor, the base of which is connected to the voltage sampling unit, and the emitter of which is grounded; the transistor is used to operate in the amplification region when the input voltage is greater than or equal to the reference voltage, and the equivalent resistance between the collector and emitter of the transistor decreases as the input voltage increases; The bypass module is configured to operate under the action of the second control signal to bypass the buck module; and to stop operating under the action of the first control signal. The control module is used to adjust the duty cycle of the first drive signal output to the buck module to a preset range based on the dynamic adjustment signal; The step-down module is used to step down the input voltage based on the first drive signal and then output the supply voltage.

2. The low-loss conversion circuit according to claim 1, characterized in that, The bypass module includes: a switching unit and a driver; The first end of the switching unit is connected to the power supply, the second end of the switching unit is connected to the output end of the circuit, and the control end of the switching unit is connected to the output end of the driver. The driver has its input terminal connected to the adjustment module and its output terminal connected to the control terminal of the switching unit. The switching unit is used to turn on under the action of the second control signal and turn off under the action of the first control signal.

3. The low-loss conversion circuit according to claim 1 or 2, characterized in that, The adjustment module is further configured to output a first enable signal to the enable terminal of the control module when the input voltage is greater than or equal to the reference voltage, so that the control module adjusts the duty cycle of the first drive signal output to the buck module to be within a preset range based on the dynamic adjustment signal; and to output a second enable signal to the enable terminal of the control module when the input voltage is less than the reference voltage, so that the control module stops working.

4. The low-loss conversion circuit according to claim 1, characterized in that, The adjustment module further includes: A voltage sampling unit is used to acquire the input voltage; The comparison unit is configured to output the second control signal when the input voltage is less than the reference voltage, and to output the first control signal when the input voltage is greater than or equal to the reference voltage; The input terminal of the enable control subunit is connected to the output terminal of the comparator unit, and the input terminal of the adjustable voltage divider unit is connected to the voltage sampling unit.

5. The low-loss conversion circuit according to claim 4, characterized in that, The voltage sampling unit includes: a fifth resistor, a seventh resistor, and a voltage follower; The first end of the fifth resistor is connected to the power supply, the second end of the fifth resistor is connected to the first end of the seventh resistor and the non-inverting input of the voltage follower, the second end of the seventh resistor is grounded, and the inverting input of the voltage follower is connected to the output of the voltage follower.

6. The low-loss conversion circuit according to claim 4, characterized in that, The second control signal is a high-level signal, the first control signal is a low-level signal, and the comparison unit includes: The comparator has its inverting input connected to the voltage sampling unit, its non-inverting input connected to the reference power supply, and its output connected to the bypass module. The comparator outputs a high-level signal when the input voltage is less than the reference voltage and outputs a low-level signal when the input voltage is greater than or equal to the reference voltage.

7. The low-loss conversion circuit according to claim 1, characterized in that, The control module is used to adjust the duty cycle of the first drive signal output to the step-down module to be within the preset range when the voltage of the dynamic adjustment signal is less than a preset value.

8. An energy storage system, characterized in that, The energy storage system includes a low-loss conversion circuit as described in any one of claims 1 to 7, wherein the circuit output terminal of the low-loss conversion circuit is connected to multiple DC output interfaces of the energy storage system.

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