Voltage regulating circuit, control method thereof and driving equipment

Abstract

The invention discloses a voltage regulating circuit, a control method thereof and driving equipment, and relates to the technical field of voltage conversion. The circuit comprises a transformer, a first switch, a second switch, a third switch, a fourth switch, a short-circuit protection switch and an output capacitor, the starting end of the first secondary side is electrically connected with the short-circuit protection switch and the ending end of the second secondary side, the short-circuit protection switch is electrically connected with the first end of the output capacitor, the third switch is electrically connected with the starting end of the second secondary side, the fourth switch and the second end of the output capacitor, and the fourth switch is electrically connected with the ending end of the first secondary side; the first switch, the third switch and the fourth switch are simultaneously conducted for a first preset duration, and / or the second switch, the third switch and the fourth switch are simultaneously conducted for a second preset duration, so that the output gain is adjusted; and the short-circuit protection switch is used for being switched off when the first switch, the third switch and the fourth switch are simultaneously switched on for a first preset duration or the second switch, the third switch and the fourth switch are simultaneously switched on for a second preset duration.

Description

Technical Field

[0001] This application relates to the field of voltage conversion technology, specifically to a voltage regulation circuit and its control method, and a driving device. Background Technology

[0002] Compared to traditional gasoline vehicles, electric vehicles require a new path to charge the onboard low-voltage battery (e.g., 12V) through a high-voltage battery pack (e.g., 300-1000V) to prevent it from running out of power. This necessitates the use of high-to-low voltage DC-DC converter circuits. Traditional solutions primarily employ single-stage and two-stage approaches. Single-stage solutions often utilize phase-shifted full-bridge and LLC converters. While these require fewer components and are simpler to control than two-stage solutions, they struggle to meet the requirements for wide voltage regulation ratios and high efficiency. Two-stage solutions, building upon single-stage solutions, add a voltage pre-control stage, reducing the voltage regulation range of the second stage and improving system efficiency. However, compared to single-stage solutions, this approach uses more components and adds an extra control stage, increasing software complexity. Summary of the Invention

[0003] Purpose of the invention: This application provides a voltage regulating circuit to overcome the technical problems of existing devices having complex structures or being unable to meet the requirements of wide-range voltage regulation ratio and high efficiency; another purpose of this application is to provide a control method for a voltage regulating circuit; another purpose of this application is to provide a driving device.

[0004] Technical Solution: An embodiment of this application describes a voltage regulating circuit, comprising: a transformer, a first switch, a second switch, a third switch, a fourth switch, a short-circuit protection switch, and an output capacitor; wherein the transformer includes a primary side, a first secondary side, and a second secondary side; the first switch and the second switch form a half-bridge and are disposed on the primary side; the starting end of the first secondary side is electrically connected to the short-circuit protection switch and the ending end of the second secondary side, respectively; the short-circuit protection switch is also electrically connected to the first end of the output capacitor; the third switch is electrically connected to the starting end of the second secondary side, the fourth switch, and the second end of the output capacitor, respectively; the fourth switch is also electrically connected to the ending end of the first secondary side.

[0005] Wherein, the first switch, the third switch and the fourth switch are simultaneously turned on for a first preset duration, and / or the second switch, the third switch and the fourth switch are simultaneously turned on for a second preset duration, so as to adjust the output gain of the voltage regulating circuit;

[0006] The short-circuit protection switch is used to disconnect when the first switch, the third switch, and the fourth switch are simultaneously turned on for a first preset time, or when the second switch, the third switch, and the fourth switch are simultaneously turned on for a second preset time.

[0007] Accordingly, the control method for a voltage regulating circuit described in this application includes: adjusting the output gain of the voltage regulating circuit by controlling the first switch, the third switch and the fourth switch to be turned on simultaneously for a first preset duration, and / or the second switch, the third switch and the fourth switch to be turned on simultaneously for a second preset duration.

[0008] Furthermore, the short-circuit protection switch is disconnected when the first switch, the third switch, and the fourth switch are simultaneously turned on for a first preset duration, or when the second switch, the third switch, and the fourth switch are simultaneously turned on for a second preset duration.

[0009] Accordingly, the driving device described in this application includes: a high-voltage battery pack, a low-voltage battery pack, and a voltage regulating circuit as described above; wherein the high-voltage battery pack charges the low-voltage battery pack through the voltage regulating circuit.

[0010] Beneficial Effects: Compared with the prior art, the voltage regulating circuit and its control method and driving device of the present application embodiment include: a transformer, a first switch, a second switch, a third switch, a fourth switch, a short-circuit protection switch, and an output capacitor; wherein, the transformer includes a primary side, a first secondary side, and a second secondary side; the first switch and the second switch form a half-bridge and are disposed on the primary side; the starting end of the first secondary side is electrically connected to the short-circuit protection switch and the ending end of the second secondary side respectively, the short-circuit protection switch is also electrically connected to the first end of the output capacitor, the third switch is electrically connected to the starting end of the second secondary side, the fourth switch, and the second end of the output capacitor respectively, and the fourth switch is also electrically connected to the ending end of the first secondary side; wherein, the first switch, the third switch, and the fourth switch are simultaneously turned on for a first preset duration, and / or the second switch, the third switch, and the fourth switch are simultaneously turned on for a second preset duration, so as to adjust the output gain of the voltage regulating circuit; the short-circuit protection switch is used to disconnect when the first switch, the third switch, and the fourth switch are simultaneously turned on for a first preset duration, or when the second switch, the third switch, and the fourth switch are simultaneously turned on for a second preset duration. Therefore, this circuit can achieve the following: by setting up a transformer, a first switch, a second switch, a third switch, a fourth switch, and a short-circuit protection switch, the third and fourth switches on the secondary side of the transformer are used for full-wave rectification and also multiplexed as switching transistors. In conjunction with the first and second switches on the primary side of the transformer, the third and fourth switches are simultaneously short-circuited. The output gain of the circuit is adjusted by regulating the duration of the simultaneous short circuit of the third and fourth switches, thereby adjusting the voltage range, achieving a wider range of voltage regulation, and improving voltage conversion efficiency. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments 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.

[0012] Figure 1 This is a schematic diagram of a voltage regulation circuit provided in an embodiment of this application;

[0013] Figure 2 This is a timing diagram of a switch adjustment signal provided in an embodiment of this application;

[0014] Figure 3 This is a schematic diagram of the discrete AC / DC equivalent circuit of a voltage regulating circuit provided in the embodiments of this application;

[0015] Figure 4 This is a waveform diagram of a key node in the voltage circuit provided in the embodiments of this application;

[0016] Figure 5 This is a schematic diagram of the state trajectory of a single working cycle provided in the embodiments of this application;

[0017] Figure 6 This is a schematic diagram showing the relationship between the duration of simultaneous short circuit of the third and fourth switches and the output gain provided in the embodiments of this application;

[0018] Figure 7 This is a schematic diagram of a simulation calculation gain comparison curve provided in the embodiments of this application;

[0019] Figure 8 This is a schematic diagram of another voltage regulation circuit provided in the embodiments of this application;

[0020] Figure 9 This is a schematic diagram of another voltage regulation circuit provided in the embodiments of this application;

[0021] Figure 10 This is a flowchart of a control method for a voltage regulation circuit provided in the embodiments of this application.

[0022] Figure label:

[0023] Q1 - First switch; Q2 - Second switch; Q3 - Third switch; Q4 - Fourth switch; Tx - Transformer; T0 - Primary side; T1 - First secondary side; T2 - Second secondary side; Cout - Output capacitor; K0 - Short circuit protection switch; Rload - Load; Lr - Resonant inductor; Cr1 - First resonant capacitor; Cr2 - Second resonant capacitor; D1 - First diode; D2 - Second diode; D3 - Third diode; D4 - Fourth diode; D5 - Fifth diode; C1 - First capacitor; C2 - Second capacitor; C3 - Third capacitor; C4 - Fourth capacitor; Q0 - Switching MOSFET. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0025] It should be understood that although the terms first, second, etc., may be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another. Therefore, the first component discussed below may be referred to as the second component without departing from the teachings of this application. As used herein, the term "and / or" includes all combinations of any and more of the associated listed items.

[0026] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of exemplary embodiments and may not be to scale. The modules or processes shown in the drawings are not necessarily essential for implementing this application and therefore should not be used to limit the scope of protection of this application.

[0027] It should be noted that the embodiments of this application are applicable to voltage conversion in driving equipment, such as high-to-low voltage conversion. For example, in scenarios where an electric vehicle charges its low-voltage battery (12V) through a high-voltage battery pack (e.g., 300-1000V) to prevent depletion. In the conversion from high voltage to low voltage, this voltage regulation circuit can periodically short-circuit the third switch Q3 and the fourth switch Q4, thereby adjusting the output gain of the circuit, achieving a wider range of voltage regulation, and improving voltage conversion efficiency. Figure 1 This is a schematic diagram of a voltage regulation circuit provided in an embodiment of this application. Please refer to... Figure 1The voltage regulating circuit includes: a transformer Tx, a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4, a short-circuit protection switch K0, and an output capacitor Cout; wherein, the transformer Tx includes a primary side T0, a first secondary side T1, and a second secondary side T2; the first switch Q1 and the second switch Q2 form a half-bridge and are disposed on the primary side T0; the starting end of the first secondary side T1 is electrically connected to the short-circuit protection switch K0 and the ending end of the second secondary side T2, respectively; the short-circuit protection switch K0 is also electrically connected to the first end of the output capacitor Cout; the third switch Q3 is electrically connected to the starting end of the second secondary side T2, the fourth switch Q4, and the fifth switch Q5; the first switch Q1 and the second switch Q2 form a half-bridge and are disposed on the primary side T0; the starting end of the first secondary side T1 is electrically connected to the ending end of the second secondary side T1, the second switch Q2 is electrically connected to the ending end of the second secondary side T1, the third switch Q3 is electrically connected to the ending end of the fourth secondary side T1, the fifth switch Q4 is electrically connected to the ending end of the second secondary side T1, the sixth switch Q2, and the seventh switch Q4; the first switch Q1 is electrically connected to the first secondary side T1, the seventh switch Q2, and the eighth ... Switch Q4 and the second terminal of output capacitor Cout are electrically connected, and the fourth switch Q4 is also electrically connected to the end terminal of the first secondary side T1; wherein, the first switch Q1, the third switch Q3 and the fourth switch Q4 are simultaneously turned on for a first preset time, and / or the second switch Q2, the third switch Q3 and the fourth switch Q4 are simultaneously turned on for a second preset time, so as to adjust the output gain of the voltage regulating circuit; the short-circuit protection switch K0 is used to disconnect when the first switch Q1, the third switch Q3 and the fourth switch Q4 are simultaneously turned on for a first preset time, or when the second switch Q2, the third switch Q3 and the fourth switch Q4 are simultaneously turned on for a second preset time.

[0028] See Figure 1 ,according to Figure 1 From the circuit structure of the first switch Q1, second switch Q2, third switch Q3, fourth switch Q4, short-circuit protection switch K0, and output capacitor Cout, it can be seen that when the first switch Q1, the third switch Q3, and the fourth switch Q4 are all turned on simultaneously, the third switch Q3 and the fourth switch Q4 are simultaneously short-circuited. When the second switch Q2, the third switch Q3, and the fourth switch Q4 are all turned on simultaneously, the third switch Q3 and the fourth switch Q4 are also simultaneously short-circuited. At this time, by setting the short-circuit protection switch K0 in the circuit and controlling the short-circuit protection switch K0 to open when the third switch Q3 and the fourth switch Q4 are short-circuited, the voltage on the secondary side of the transformer is prevented from being short-circuited and released. For example, it prevents the voltage from not discharging from the output capacitor Cout to ground, thereby protecting the circuit and allowing the circuit to operate normally.

[0029] In this circuit, the third switch Q3 and the fourth switch Q4 are used for full-wave rectification in the secondary circuit. They are also multiplexed to work with the first switch Q1 and the second switch Q2 in the primary circuit. By simultaneously conducting with either the first switch Q1 or the second switch Q2 for a certain duration, the third switch Q3 and the fourth switch Q4 are simultaneously short-circuited. The duration of this short-circuit adjustment regulates the circuit's output gain, thereby adjusting the voltage range and achieving wider voltage regulation, as well as improving voltage conversion efficiency. Furthermore, by multiplexing the third and fourth switches in the secondary circuit, wide-range voltage regulation and full-wave rectification can be achieved while further simplifying the circuit structure, reducing the number of components, lowering design costs, and improving efficiency.

[0030] The duration of simultaneous short circuits of the third switch Q3 and the fourth switch Q4 is proportional to the output gain of the voltage regulation circuit.

[0031] The first preset duration and the second preset duration can be the same or different. The specific settings can be made according to the actual situation, and no specific restrictions are made here.

[0032] It should be noted that within one switching adjustment cycle, adjustment can be achieved by simultaneously short-circuiting the third switch Q3 and the fourth switch Q4 once or multiple times. For example, within one switching adjustment cycle, the first switch Q1, the third switch Q3, and the fourth switch Q4 can be controlled to conduct simultaneously for a first preset duration, thereby adjusting the output gain of the circuit through the first preset duration to achieve voltage regulation over a wider range. Similarly, within one switching adjustment cycle, the second switch Q2, the third switch Q3, and the fourth switch Q4 can be controlled to conduct simultaneously for a second preset duration, thereby adjusting the output gain of the circuit through the second preset duration to achieve voltage regulation over a wider range. Furthermore, within one switching adjustment cycle, the first switch Q1, the third switch Q3, and the fourth switch Q4 can be controlled to conduct simultaneously for a first preset duration, and the second switch Q2, the third switch Q3, and the fourth switch Q4 can also conduct simultaneously for a second preset duration, thereby adjusting the output gain of the circuit through both the first and second preset durations to achieve voltage regulation over a wider range.

[0033] For example, the operation of the voltage regulating circuit is illustrated by adjusting the voltage using a first preset duration and a second preset duration within one switching adjustment cycle (the same applies below, and will not be repeated). In the technical solution of this application embodiment, the working principle of the voltage regulating circuit is as follows: For example, refer to... Figure 1Within one switching adjustment cycle, the first switch Q1, the third switch Q3, and the fourth switch Q4 are simultaneously turned on for a first preset duration. During this time, the third switch Q3 and the fourth switch Q4 are simultaneously short-circuited. Simultaneously, during this first preset duration, the second switch Q2 and the short-circuit protection switch K0 are turned off to protect the circuit and prevent the voltage on the secondary side of the transformer from being released due to the short circuit. At this time, the output gain of the circuit can be adjusted by the first preset duration to achieve a wider range of voltage regulation and improve voltage conversion efficiency. Then, the second switch Q2, the third switch Q3, and the fourth switch Q4 are simultaneously turned on for a second preset duration. During this second preset duration, the third switch Q3 and the fourth switch Q4 are simultaneously short-circuited. Again, during this second preset duration, the first switch Q1 and the short-circuit protection switch K0 are turned off to protect the circuit and prevent the voltage on the secondary side of the transformer from being released due to the short circuit. At this time, the output gain of the circuit can be adjusted by the second preset duration to achieve a wider range of voltage regulation and improve voltage conversion efficiency. Therefore, by periodically short-circuiting the third switch Q3 and the fourth switch Q4, the output gain of the circuit is adjusted, achieving a wider range of voltage regulation and improving voltage conversion efficiency. Furthermore, by multiplexing the third and fourth switches on the secondary side, wide-range voltage regulation and full-wave rectification can be achieved while further simplifying the circuit structure, reducing the number of components used, lowering design costs, and improving efficiency.

[0034] Based on the above embodiments, optionally, the first preset switch adjustment signal of the first switch and the second preset switch adjustment signal of the second switch are complementary.

[0035] Within the same switching adjustment cycle, the on-time of the first switch and the off-time of the second switch are the same, and similarly, the off-time of the first switch and the on-time of the second switch are the same. In other words, when the first switch is on, the second switch is off, and when the first switch is off, the second switch is on.

[0036] For example, the preset switch adjustment signal of each switch can be a duty cycle adjustment signal. Specifically, the first preset switch adjustment signal of the first switch and the second preset switch adjustment signal of the second switch are complementary and conduct with a 50% duty cycle.

[0037] Based on the above embodiments, optionally, the first preset duration is equal to the second preset duration.

[0038] The specific values ​​of the first preset duration and the second preset duration can be set according to the actual situation, and no specific limitation is made here.

[0039] Continue reading Figure 1The voltage regulating circuit also includes: a first resonant capacitor Cr1, a second resonant capacitor Cr2, a resonant inductor Lr, a load Rload, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a first capacitor C1, a second capacitor C2, a third capacitor C3, and a fourth capacitor C4. The first and second resonant capacitors Cr1 and Cr2 form a passive bridge arm, the first switch Q1 and the second switch Q2 form an active bridge arm, and the third switch Q3 and the fourth switch Q4 form a full-wave rectifier circuit on the secondary side. The resonant inductor Lr, the first resonant capacitor Cr1, and the second resonant capacitor Cr2 form a resonant cavity, which has the advantages of low turn-off current and high conversion efficiency.

[0040] The first resonant capacitor Cr1 and the second resonant capacitor Cr2 in the passive half-bridge have two functions: first, they block DC current to prevent transformer magnetization; second, they provide resonance to reduce the turn-off current of the primary-side switch and improve system efficiency.

[0041] Among them, the first switch Q1, the second switch Q2, the third switch Q3 and the fourth switch Q4 can be switching transistors, such as MOSFET transistors, etc. The specific settings can be made according to the actual situation, and no specific restrictions are made here.

[0042] Based on the above embodiments, optionally, the preset switch adjustment signal for each switch can be a duty cycle signal. Figure 2 This is a timing diagram of a switch adjustment signal provided in an embodiment of this application. For the first preset switch adjustment signal of the first switch Q1, please refer to [link to relevant documentation]. Figure 2 Please refer to curve L1 in the figure, and the second preset switch adjustment signal of the second switch Q2. Figure 2 Please refer to curve L2 in the figure, and the third preset switch adjustment signal of the third switch Q3. Figure 2 Please refer to curve L3 in the figure, and the fourth preset switch adjustment signal of the fourth switch Q4. Figure 2Curve L4 in the diagram. For example, taking one switching adjustment cycle T as an example, according to curves L1 and L2, the first preset switching adjustment signal of the first switch Q1 is complementary to the second preset switching adjustment signal of the second switch Q2, and they are turned on with a 50% duty cycle and turned off with a 50% duty cycle. Furthermore, within the first preset duration Dboost1, the first switch Q1, the third switch Q3, and the fourth switch Q4 are simultaneously turned on (i.e., the third switch Q3 and the fourth switch Q4 are simultaneously short-circuited), and the second switch Q2 is turned off. Within the second preset duration Dboost2, the second switch Q2, the third switch Q3, and the fourth switch Q4 are simultaneously turned on (i.e., the third switch Q3 and the fourth switch Q4 are simultaneously short-circuited), and the first switch Q1 is turned off. Therefore, by adjusting the first preset duration Dboost1 and the second preset duration Dboost2, the output gain of the circuit can be adjusted, thereby achieving a wider range of voltage regulation and improving voltage conversion efficiency.

[0043] Figure 3 This is a schematic diagram of the discrete AC / DC equivalent circuit of a voltage regulating circuit provided in an embodiment of this application. Figure 4 This is a waveform diagram of a key node in the voltage circuit provided in the embodiments of this application. Figure 5 This is a schematic diagram of the state trajectory of a single working cycle provided in an embodiment of this application. For example, for ease of analysis, [the diagram is shown]. Figure 1 The circuit in the diagram is equivalent to Figure 3 The discrete AC / DC equivalent circuit is shown. Figure 3 In the equivalent circuit, equivalent power supplies V2 and V3 are obtained, both with a voltage value of Vin / 2, where Vin is the input voltage of power supply V1. (See also...) Figure 4 Curve S1 is the curve of the change of current ILr of resonant inductor Lr, curve S2 is the curve of the change of voltage Vcr of resonant capacitor Cr, curve S3 is the curve of the change of voltage Vsec*N (N is the turns ratio of the primary and secondary sides of the transformer) across the transformer, curve S4 is the curve of the change of voltage Vpri between circuit node P+ and node P-, and curve S5 is the curve of the change of input current Iin.

[0044] The t0-t1 segment is the duration of the simultaneous short circuit of the third switch Q3 and the fourth switch Q4, which is the first preset duration Dboost1. The T3-t4 segment is the duration of the simultaneous short circuit of the third switch Q3 and the fourth switch Q4, which is the second preset duration Dboost2.

[0045] See Figure 4The working principle of this voltage regulation circuit is as follows: Mode 1 (t0-t1): At time t0, the first switch Q1, the third switch Q3, and the fourth switch Q4 are turned on, and the second switch Q2 is turned off. The voltage input Vin, the first switch Q1, the resonant inductor Lr, the primary side of the transformer T0, and the second resonant capacitor Cr2 form a loop. Due to the short circuit of the third switch Q3 and the fourth switch Q4, the secondary side of the equivalent transformer is short-circuited. At this time, the voltage Vsec*N across the secondary side of the transformer is zero, and the voltage Vpri between the circuit nodes P+ and P- is Vin / 2. The current of the resonant inductor rises linearly, and energy is stored through the resonant inductor, thereby raising the voltage and increasing the output voltage gain to achieve voltage regulation. Mode 2 (t1-t2): At time t1, the first switch Q1 and the third switch Q3 are on, while the second switch Q2 and the fourth switch Q4 are off. At this time, the voltage on the second secondary side of the transformer is positive at the top and negative at the bottom. The current flows out from the end of the second secondary side, passes through the short-circuit protection switch, the output capacitor Cout, and the third switch Q3, and flows back to the beginning of the second secondary side. The voltage Vsec*N across the transformer secondary side is a high-level signal. The resonant inductor and resonant capacitor resonate, the current in the resonant inductor decreases, and the voltage in the resonant capacitor increases. Mode 3 (t2-t3): At time t2, the first and third switches are on, while the second and fourth switches are off. Due to the resonance of the transformer primary side, the current on the transformer secondary side gradually decreases until it reaches zero at time t2. At this time, the short-circuit protection switch opens to prevent the voltage on the transformer secondary side from being released due to the short circuit. At this time, the current in the resonant inductor is zero. Mode 4 (t3-t4): At time t3, the second switch Q2, the third switch Q3, and the fourth switch Q4 are turned on, and the first switch Q1 is turned off. The voltage input Vin, the first resonant capacitor Cr1, the primary side of the transformer T0, the resonant inductor Lr, and the second switch Q2 form a loop. Due to the short circuit of the third switch Q3 and the fourth switch Q4, the secondary side of the equivalent transformer is short-circuited. At this time, the voltage Vsec*N across the secondary side of the transformer is zero, and the voltage Vpri between the circuit nodes P+ and P- is Vin / 2. The current of the resonant inductor rises linearly, storing energy through the resonant inductor, thereby raising the voltage and increasing the output voltage gain to achieve voltage regulation. Mode 5 (t4-t5): At time t4, the second switch Q2 and the fourth switch Q4 are turned on, and the first switch Q1 and the third switch Q3 are turned off. At this time, the voltage on the first secondary side of the transformer is positive at the bottom and negative at the top. The current flows out from the beginning of the first secondary side, passes through the short-circuit protection switch, the output capacitor Cout, and the fourth switch Q4 in sequence, and flows back to the end of the first secondary side. The voltage Vsec*N across the secondary side of the transformer is a high-level signal. The resonant inductor and the resonant capacitor resonate. The current in the resonant inductor rises, and the voltage of the resonant capacitor falls.Mode 6 (t5-t6): At time t5, due to the resonance of the primary side of the transformer, the current on the secondary side of the transformer gradually decreases until it is zero at time t5. At this time, the short-circuit protection switch is opened to prevent the voltage on the secondary side of the transformer from being released due to the short circuit. At this time, the current of the resonant inductor is zero.

[0046] For example, taking the charging of a low-voltage battery pack from a high-voltage battery pack as an example, the implementation process of this voltage regulation circuit is as follows: (See...) Figure 4First, during the t0-t1 period, the first switch Q1, the third switch Q3, and the fourth switch Q4 are turned on, while the second switch Q2 is turned off. The voltage input Vin, the first switch Q1, the resonant inductor Lr, the primary side of the transformer T0, and the second resonant capacitor Cr2 form a circuit. Due to the short circuit of the third switch Q3 and the fourth switch Q4 on the secondary side, the equivalent secondary side of the transformer is short-circuited, and the current of the resonant inductor rises linearly. Energy is stored through the resonant inductor, thereby raising the voltage and increasing the output voltage gain, thus achieving voltage regulation. During the t1-t2 period, the first switch Q1 and the third switch Q3 are turned on, while the second switch Q2 and the fourth switch Q4 are turned off. At this time, the voltage on the second secondary side of the transformer is positive at the top and negative at the bottom. The current flows out from the end of the second secondary side, sequentially through the short-circuit protection switch, the output capacitor Cout, and the third switch Q3, flowing back to the beginning of the second secondary side. The voltage Vsec*N across the secondary side of the transformer is a high-level signal. The resonant inductor and the resonant capacitor resonate, the current of the resonant inductor decreases, and the voltage of the resonant capacitor increases. During the time interval t2-t3, the first and third switches are turned on, while the second and fourth switches are turned off. Due to the resonance of the primary side of the transformer, the current on the secondary side of the transformer gradually decreases until it reaches zero at time t2. At this point, the short-circuit protection switch is opened to prevent the voltage on the secondary side of the transformer from being released due to the short circuit. At this time, the current of the resonant inductor is zero. During the time interval t3-t4, the second switch Q2, the third switch Q3, and the fourth switch Q4 are turned on, while the first switch Q1 is turned off. The voltage input Vin, the first resonant capacitor Cr1, the primary side of the transformer T0, the resonant inductor Lr, and the second switch Q2 form a circuit. Due to the short circuit of the third switch Q3 and the fourth switch Q4, the equivalent secondary side of the transformer is short-circuited. The current of the resonant inductor rises linearly, storing energy through the resonant inductor, thereby raising the voltage and increasing the output voltage gain to achieve voltage regulation. During the t4-t5 period, the second switch Q2 and the fourth switch Q4 are turned on, while the first switch Q1 and the third switch Q3 are turned off. At this time, the voltage on the first secondary side of the transformer is positive at the bottom and negative at the top. The current flows out from the beginning of the first secondary side, passes through the short-circuit protection switch, the output capacitor Cout, and the fourth switch Q4, and flows back to the end of the first secondary side. The voltage Vsec*N across the transformer secondary side is a high-level signal. The resonant inductor and resonant capacitor resonate, the current in the resonant inductor increases, and the voltage in the resonant capacitor decreases. During the t5-t6 period, due to the resonance of the transformer primary side, the current on the transformer secondary side gradually decreases until it reaches zero at t5. At this time, the short-circuit protection switch opens to prevent the voltage on the transformer secondary side from being released due to a short circuit. The current in the resonant inductor is zero at this time. This allows the high-voltage battery pack to charge the low-voltage battery pack through this voltage regulation circuit, achieving a wider voltage regulation range and improving voltage conversion efficiency and charging efficiency.

[0047] pass Figure 3 Equivalent circuit and Figure 4The waveforms of key nodes are analyzed using a state trajectory analysis method. Simulation can obtain the state trajectory for each working cycle, such as... Figure 5 As shown. For example, see [link to relevant documentation]. Figure 5 , Figure 5 The x-coordinate in the middle is Figure 4 The voltage Vcr of the resonant capacitor Cr in the middle. Figure 5 The vertical axis in the figure is Figure 4 The current ILr in the resonant inductor Lr in the middle, Figure 5 Points A, B, C, and D in the diagram correspond to... Figure 4 The times t0, t1, t3, and t4 are given. The time from point A to point B corresponds to... Figure 4 The time interval from t0 to t1, from point B to point C, corresponds to... Figure 4 In the time interval t1 to t2, point C corresponds to Figure 4 The time interval from t2 to t3, from point C to point D, corresponds to Figure 4 The time interval from t3 to t4 corresponds to the time interval from point D to point A. Figure 4 In the time interval t4 to t5, point A corresponds to Figure 4 The time interval from t5 to t6 in the equation can be used to derive the relationship between the duration of the simultaneous short circuit of the third and fourth switches (Dboost) and the output gain time of the circuit:

[0048]

[0049] Among them, D boost The duration of simultaneous short circuits of the third and fourth switches, M is the output gain of the circuit, n is the turns ratio of the primary and secondary sides of the transformer, and f sw For switching frequency (e.g.) Figure 4 (the reciprocal of time t0-t6), C r For the resonant capacitor (i.e., the parallel connection of the first resonant capacitor Cr1 and the second resonant capacitor Cr2), R load For the load resistance, w r ω is the angular frequency at the resonant point.

[0050] in,

[0051]

[0052] Figure 6 This is a schematic diagram illustrating the relationship between the duration of simultaneous short circuits of the third and fourth switches and the output gain provided in this embodiment of the application. Based on the aforementioned relationship between the duration of simultaneous short circuits of the third and fourth switches, Dboost, and the output gain time of the circuit, the derivative of the duration of simultaneous short circuits of the third and fourth switches, Dboost, with respect to M is calculated as follows: Figure 6 As shown, the derivative is greater than zero, proving that the duration D of the simultaneous short circuit of the third and fourth switches is... boostThe output gain M of the circuit exhibits a monotonically increasing characteristic.

[0053] Figure 7 This is a schematic diagram of a simulation calculation gain comparison curve provided in an embodiment of this application. Curve F1 shows the relationship between Dboost calculated according to the above formula and the output gain M of the circuit, while curve F2 shows the relationship between Dboost calculated through simulation and the output gain M of the circuit. Figure 7 The simulation calculations and gain comparisons proved the correctness of the relationship between the duration of the simultaneous short circuit of the third and fourth switches, Dboost, and the output gain time of the circuit.

[0054] Based on the above embodiments, optionally, the first preset duration is proportional to the output gain of the voltage regulation circuit, and the second preset duration is proportional to the output gain of the voltage regulation circuit.

[0055] The first preset duration is proportional to the output gain of the voltage regulation circuit, and the second preset duration is also proportional to the output gain of the voltage regulation circuit. Therefore, by controlling the first switch Q1, the third switch Q3, and the fourth switch Q4 to be simultaneously turned on for the first preset duration, and / or the second switch Q2, the third switch Q3, and the fourth switch Q4 to be simultaneously turned on for the second preset duration, the output gain of the voltage regulation circuit can be adjusted by regulating the duration of the simultaneous short circuit of the third and fourth switches. This allows for adjustment of the circuit's voltage range, achieving a wider range of voltage regulation and improving voltage conversion efficiency.

[0056] Based on the above embodiments, optionally, the ratio of the first preset duration to the switching cycle and the ratio of the second preset duration to the switching cycle are both greater than zero and less than 0.5.

[0057] In this scenario, when the first switch Q1, the third switch Q3, and the fourth switch Q4 are simultaneously turned on, the duration of the short circuit between the third switch Q3 and the fourth switch Q4 accounts for a proportion greater than zero and less than 0.5% of the total switching cycle. Similarly, when the second switch Q2, the third switch Q3, and the fourth switch Q4 are simultaneously turned on, the duration of the short circuit between the third switch Q3 and the fourth switch Q4 also accounts for a proportion greater than zero and less than 0.5% of the total switching cycle.

[0058] Based on the above embodiments, optionally, the short-circuit protection switch includes at least one of a diode and a switching MOSFET.

[0059] Figure 8 This is a schematic diagram of another voltage regulation circuit provided in an embodiment of this application. Exemplary, Figure 8 This illustrates an implementation where the short-circuit protection switch is a diode. For example, it uses the charging of a low-voltage battery pack from a high-voltage battery pack as an example, combined with... Figure 4 and Figure 8 During the time interval t0-t1, when the first switch Q1, the third switch Q3, and the fourth switch Q4 are simultaneously turned on, the third switch Q3 and the fourth switch Q4 are simultaneously short-circuited. At this time, the voltage Vsec*N across the secondary side of the transformer is zero, and the fifth diode D5 cannot conduct. This prevents the voltage on the secondary side of the transformer from being released due to the short circuit when the third switch Q3 and the fourth switch Q4 are short-circuited, thus protecting the circuit and ensuring its normal operation. Similarly, during the time interval t3-t4, when the second switch Q2, the third switch Q3, and the fourth switch Q4 are simultaneously turned on, the third switch Q3 and the fourth switch Q4 are simultaneously short-circuited. At this time, the voltage Vsec*N across the secondary side of the transformer is zero, and the fifth diode D5 cannot conduct. This prevents the voltage on the secondary side of the transformer from being released due to the short circuit when the third switch Q3 and the fourth switch Q4 are short-circuited, thus protecting the circuit and ensuring its normal operation. Furthermore, during the period t1-t3, the first and third switches are on, while the second and fourth switches are off. Due to the resonance of the transformer primary side, the current on the transformer secondary side gradually decreases until it reaches zero at time t2. At this time, the fifth diode D5 is disconnected as no current flows through it, thus preventing the voltage on the transformer secondary side from being released due to a short circuit. Similarly, during the period t4-t6, the second and fourth switches are on, while the first and third switches are off. Due to the resonance of the transformer primary side, the current on the transformer secondary side gradually decreases until it reaches zero at time t5. At this time, the fifth diode D5 is disconnected as no current flows through it, thus preventing the voltage on the transformer secondary side from being released due to a short circuit.

[0060] Figure 9 This is a schematic diagram of another voltage regulation circuit provided in an embodiment of this application. Exemplary, Figure 9 This illustrates an implementation where the short-circuit protection switch is a switching MOSFET. For example, it uses the charging of a low-voltage battery pack from a high-voltage battery pack as an example, combined with... Figure 4 and Figure 9During the time interval t0-t1, when the first switch Q1, the third switch Q3, and the fourth switch Q4 are simultaneously turned on, the third switch Q3 and the fourth switch Q4 are simultaneously short-circuited. At this time, the voltage Vsec*N across the secondary side of the transformer is zero. The control switch MOSFET Q0 is then turned off, preventing the voltage on the secondary side of the transformer from being released due to the short circuit of the third switch Q3 and the fourth switch Q4, thus protecting the circuit and ensuring its normal operation. Similarly, during the time interval t3-t4, when the second switch Q2, the third switch Q3, and the fourth switch Q4 are simultaneously turned on, the third switch Q3 and the fourth switch Q4 are also simultaneously short-circuited. At this time, the voltage Vsec*N across the secondary side of the transformer is zero. By turning off the control switch MOSFET Q0, the voltage on the secondary side of the transformer from being released due to the short circuit of the third switch Q3 and the fourth switch Q4 can be prevented, for example, preventing the voltage from being released to ground through the output capacitor Cout, thus protecting the circuit and ensuring its normal operation. Furthermore, during the period t1-t3, the first and third switches are on, while the second and fourth switches are off. Due to the primary-side resonance of the transformer, the current on the secondary side of the transformer gradually decreases until it reaches zero at time t2. At this time, the control switch MOSFET Q0 is turned off, thus preventing the voltage on the secondary side of the transformer from being released due to a short circuit. Similarly, during the period t4-t6, the second and fourth switches are on, while the first and third switches are off. Due to the primary-side resonance of the transformer, the current on the secondary side of the transformer gradually decreases until it reaches zero at time t5. At this time, the control switch MOSFET Q0 is turned off, thus preventing the voltage on the secondary side of the transformer from being released due to a short circuit.

[0061] Figure 10 This is a flowchart illustrating a control method for a voltage regulating circuit provided in an embodiment of this application. Correspondingly, an embodiment of this application also provides a control method for a voltage regulating circuit. Please refer to... Figure 10 The method includes the following steps:

[0062] Step 110: Adjust the output gain of the voltage regulation circuit by controlling the first switch, the third switch and the fourth switch to be turned on simultaneously for a first preset duration, and / or the second switch, the third switch and the fourth switch to be turned on simultaneously for a second preset duration.

[0063] Step 120: Disconnect the short-circuit protection switch when the first switch, the third switch, and the fourth switch are simultaneously turned on for a first preset time, or when the second switch, the third switch, and the fourth switch are simultaneously turned on for a second preset time.

[0064] In this embodiment, the voltage regulating circuit includes a transformer, a first switch, a second switch, a third switch, a fourth switch, a short-circuit protection switch, and an output capacitor. The first and second switches form a half-bridge and are located on the primary side. The starting end of the first secondary side is electrically connected to the short-circuit protection switch and the ending end of the second secondary side, respectively. The short-circuit protection switch is also electrically connected to the first end of the output capacitor. The third switch is electrically connected to the starting end of the second secondary side, the fourth switch, and the second end of the output capacitor, respectively. The fourth switch is also electrically connected to the ending end of the first secondary side. The short-circuit protection switch is used to disconnect when the first, third, and fourth switches are simultaneously turned on for a first preset time, or when the second, third, and fourth switches are simultaneously turned on for a second preset time, to prevent the voltage on the secondary side of the transformer from being released due to a short circuit when the third and fourth switches are short-circuited.

[0065] The technical solution of this application embodiment provides a control method for a voltage regulating circuit. This method includes: controlling the first switch, the third switch, and the fourth switch to be simultaneously turned on for a first preset duration, and / or the second switch, the third switch, and the fourth switch to be simultaneously turned on for a second preset duration, to adjust the output gain of the voltage regulating circuit; and disconnecting the short-circuit protection switch when the first switch, the third switch, and the fourth switch are simultaneously turned on for the first preset duration, or the second switch, the third switch, and the fourth switch are simultaneously turned on for the second preset duration. Therefore, this method can achieve the following: by setting a transformer, a first switch, a second switch, a third switch, a fourth switch, and a short-circuit protection switch, the third and fourth switches on the secondary side of the transformer are used for full-wave rectification and also multiplexed as switching transistors, and cooperate with the first and second switches on the primary side of the transformer to simultaneously short-circuit the third and fourth switches. The output gain of the circuit is adjusted by regulating the duration of the simultaneous short circuit of the third and fourth switches, thereby adjusting the voltage range, achieving a wider range of voltage regulation, and improving voltage conversion efficiency. Furthermore, by multiplexing the third and fourth switches on the secondary side, wide-range voltage regulation and full-wave rectification can be achieved while further simplifying the circuit structure, reducing the number of components used, lowering design costs, and improving efficiency.

[0066] In some embodiments, the first preset duration is proportional to the output gain of the voltage regulation circuit, and the second preset duration is proportional to the output gain of the voltage regulation circuit.

[0067] In some embodiments, the first preset switch adjustment signal of the first switch and the second preset switch adjustment signal of the second switch are complementary.

[0068] In some embodiments, the first preset duration is equal to the second preset duration.

[0069] In some embodiments, the short-circuit protection switch includes at least one of a diode and a switching MOSFET.

[0070] In some embodiments, the ratio of the first preset duration to the switching cycle and the ratio of the second preset duration to the switching cycle are both greater than zero and less than 0.5.

[0071] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0072] Accordingly, this application also provides a driving device, which includes: a high-voltage battery pack, a low-voltage battery pack, and a voltage regulating circuit as described in any embodiment of this application; wherein the high-voltage battery pack charges the low-voltage battery pack through the voltage regulating circuit.

[0073] The voltage regulation circuit, control method, and driving device provided in the embodiments of this application have been described in detail above, and specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A voltage regulating circuit, characterized in that, include: The system comprises a transformer, a first switch, a second switch, a third switch, a fourth switch, a short-circuit protection switch, and an output capacitor. The transformer includes a primary side, a first secondary side, and a second secondary side. The first switch and the second switch form a half-bridge and are disposed on the primary side. The starting end of the first secondary side is electrically connected to the short-circuit protection switch and the ending end of the second secondary side, respectively. The short-circuit protection switch is also electrically connected to the first end of the output capacitor. The third switch is electrically connected to the starting end of the second secondary side, the fourth switch, and the second end of the output capacitor, respectively. The fourth switch is also electrically connected to the ending end of the first secondary side. Wherein, the first switch, the third switch and the fourth switch are simultaneously turned on for a first preset duration, and / or the second switch, the third switch and the fourth switch are simultaneously turned on for a second preset duration, so as to adjust the output gain of the voltage regulating circuit; The short-circuit protection switch is used to disconnect when the first switch, the third switch, and the fourth switch are simultaneously turned on for a first preset time, or when the second switch, the third switch, and the fourth switch are simultaneously turned on for a second preset time.

2. The voltage regulating circuit according to claim 1, characterized in that, The short-circuit protection switch includes at least one of a diode and a switching MOSFET.

3. The voltage regulating circuit according to claim 1, characterized in that, The first preset duration is proportional to the output gain of the voltage regulation circuit, and the second preset duration is proportional to the output gain of the voltage regulation circuit.

4. The voltage regulating circuit according to claim 1, characterized in that, The first preset switch adjustment signal of the first switch and the second preset switch adjustment signal of the second switch are complementary.

5. The voltage regulating circuit according to claim 1, characterized in that, The first preset duration is equal to the second preset duration.

6. The voltage regulating circuit according to claim 1, characterized in that, The ratio of the first preset duration to the switching cycle and the ratio of the second preset duration to the switching cycle are both greater than zero and less than 0.

5.

7. A control method for a voltage regulating circuit as described in any one of claims 1-6, characterized in that, include: The output gain of the voltage regulating circuit can be adjusted by controlling the first switch, the third switch and the fourth switch to be turned on simultaneously for a first preset duration, and / or the second switch, the third switch and the fourth switch to be turned on simultaneously for a second preset duration. Furthermore, the short-circuit protection switch is disconnected when the first switch, the third switch, and the fourth switch are simultaneously turned on for a first preset duration, or when the second switch, the third switch, and the fourth switch are simultaneously turned on for a second preset duration.

8. The control method for the voltage regulating circuit according to claim 7, characterized in that, The first preset duration is proportional to the output gain of the voltage regulation circuit, and the second preset duration is proportional to the output gain of the voltage regulation circuit.

9. The control method for the voltage regulating circuit according to claim 7, characterized in that, The first preset switch adjustment signal of the first switch and the second preset switch adjustment signal of the second switch are complementary.

10. The control method for the voltage regulating circuit according to claim 7, characterized in that, The first preset duration is equal to the second preset duration.

11. The control method for the voltage regulating circuit according to claim 7, characterized in that, The short-circuit protection switch includes at least one of a diode and a switching MOSFET.

12. The control method for the voltage regulating circuit according to claim 7, characterized in that, The ratio of the first preset duration to the switching cycle and the ratio of the second preset duration to the switching cycle are both greater than zero and less than 0.

5.

13. A driving device, characterized in that, include: A high-voltage battery pack, a low-voltage battery pack, and a voltage regulating circuit as described in any one of claims 1-6; wherein the high-voltage battery pack charges the low-voltage battery pack through the voltage regulating circuit.

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