Energy recovery circuit and electrical equipment

Abstract

The embodiment of the invention provides an energy recovery circuit, which comprises a front-end energy storage circuit, a switching circuit, a controller, a transformer, an energy absorption circuit, an energy transfer circuit and an energy control circuit, and is characterized in that when the switching circuit enters a turn-off state, the energy absorption circuit absorbs current flowing through a primary side coil of the transformer for storage; and the energy control circuit controls the energy transfer circuit to transfer the energy absorbed by the energy absorption circuit to the front-end energy storage circuit for storage. Therefore, according to the energy recovery circuit, when the switching circuit enters a turn-off state, the energy absorption circuit can prevent the current flowing through the primary side coil from forming peak voltage on the switching circuit, and high-voltage protection is carried out on the switching circuit; and the energy recovery circuit also adopts the energy transfer circuit to transfer the energy absorbed by the energy absorption circuit to the front-end energy storage circuit, so that the recovered energy is continuously transferred to the secondary coil, and the conversion efficiency of the power supply is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of switching power supplies, and in particular to an energy recovery circuit and electrical equipment. Background Art

[0002] The main switch in the switching power supply will be subjected to high voltage shock at the moment of entering the off state, causing damage to the main switch. In order to prevent the main switch from being damaged by high voltage shock, the switching voltage of the main switch is generally clamped by an absorption network in the switching power supply to suppress the switching voltage and provide high voltage protection for the main switch.

[0003] Although the absorption network can provide high voltage protection for the main switch tube, the absorption network consumes the absorbed energy, resulting in high energy loss and low energy conversion efficiency of the switching power supply. In addition, the absorption network consumes the absorbed energy, which will cause a large temperature rise inside the switching power supply, accelerate the aging of components, and thus reduce the reliability and service life of the entire system. Summary of the invention

[0004] The embodiments of the present application provide an energy recovery circuit and an electrical device, which can improve power conversion efficiency.

[0005] In a first aspect, an embodiment of the present application provides an energy recovery circuit, including:

[0006] A front-end energy storage circuit is configured to store energy, the front-end energy storage circuit comprising a first node;

[0007] A switch circuit including a second node;

[0008] A controller, electrically connected to the switch circuit, configured to control the switch circuit to enter an on state or an off state;

[0009] A transformer, comprising a coupled primary coil and a secondary coil, wherein the primary coil is electrically connected between the first node and the second node, and the primary coil is configured to transfer energy to the secondary coil based on the current output by the front-end energy storage circuit in response to the switch circuit entering an on state or an off state;

[0010] an energy absorption circuit, electrically connected to the second node, configured to absorb and store the current flowing through the primary coil in response to the switch circuit entering an off state, the energy absorption circuit comprising a third node;

[0011] an energy transfer circuit, electrically connected to the third node and also electrically connected to the front-end energy storage circuit;

[0012] The energy control circuit is electrically connected to the energy transfer circuit and is configured to control the energy transfer circuit to transfer the energy absorbed by the energy absorption circuit to the front-end energy storage circuit for storage.

[0013] In some embodiments, the energy control circuit is configured to control the energy transfer circuit to adjust the energy absorption circuit to be in a stable voltage state, so that the voltage across the primary coil is in a stable voltage state after the switching circuit is turned off, and the current flowing through the primary coil decreases evenly.

[0014] In some embodiments of the present application, the energy control circuit includes:

[0015] a voltage stabilization control circuit, electrically connected to the energy absorption circuit and the energy transfer circuit, respectively, and configured to control the energy transfer circuit to adjust the energy absorption circuit to be in a voltage stabilization state, so that the voltage across the primary coil is in a voltage stabilization state after the switch circuit is turned off, and the current flowing through the primary coil is uniformly reduced;

[0016] A delay circuit is electrically connected to the voltage stabilization control circuit and is configured to control the response of the voltage stabilization control circuit to lag behind the change of the voltage across the energy absorption circuit.

[0017] In some embodiments of the present application, the voltage stabilization control circuit includes:

[0018] a voltage detection circuit, electrically connected to the energy absorption circuit and the delay circuit, respectively, and configured to detect the voltage across the energy absorption circuit to obtain a sampled voltage, wherein the delay circuit is configured to control the sampled voltage to lag behind the change of the voltage across the energy absorption circuit;

[0019] The voltage monitoring circuit is electrically connected to the voltage detection circuit and the energy transfer circuit respectively, and is configured to control the working state of the energy transfer circuit based on the sampled voltage.

[0020] In some embodiments of the present application, the voltage detection circuit is electrically connected between the first node and the third node, and is configured to detect the voltage across the energy absorption circuit, obtain a sampled voltage, and transmit the sampled voltage to the voltage monitoring circuit.

[0021] In some embodiments of the present application, the voltage detection circuit includes a first resistor and a second resistor, one end of the first resistor is electrically connected to the third node, the other end of the first resistor and one end of the second resistor are electrically connected to a fourth node, the voltage monitoring circuit is electrically connected to the fourth node, and the other end of the second resistor is electrically connected to the first node.

[0022] In some embodiments of the present application, the voltage detection circuit includes: a first voltage sampling branch, a second voltage sampling branch, and an operational amplifier;

[0023] a first voltage sampling branch, electrically connected between the first node and the ground, the first voltage sampling branch comprising a fifth node, the inverting input terminal of the operational amplifier being electrically connected to the fifth node, and the first voltage sampling branch being configured to detect a voltage at the first node to obtain a first sampled voltage;

[0024] a second voltage sampling branch, electrically connected between the third node and the ground, the second voltage sampling branch comprising a sixth node, the non-inverting input terminal of the operational amplifier electrically connected to the sixth node, the output terminal of the operational amplifier electrically connected to the voltage monitoring circuit, and the second voltage sampling branch being configured to detect the voltage at the third node to obtain a second sampled voltage;

[0025] The operational amplifier is configured to perform signal conditioning processing on the first sampling voltage and the second sampling voltage to obtain conditioned sampling voltages.

[0026] In some embodiments of the present application, the transformer further includes an auxiliary coil, and the auxiliary coil is coupled to the primary coil;

[0027] The voltage detection circuit also includes a power input circuit, which is electrically connected to the auxiliary coil and the operational amplifier, respectively, and is configured to provide working power to the operational amplifier.

[0028] In some embodiments of the present application, the voltage monitoring circuit is configured to control the energy transfer circuit to transfer the energy absorbed by the energy absorption circuit in response to the sampling voltage being greater than a preset reference voltage; or,

[0029] The voltage monitoring circuit is configured to control the energy transfer circuit to stop transferring the energy absorbed by the energy absorption circuit in response to the sampling voltage being less than or equal to a preset reference voltage.

[0030] In some embodiments of the present application, the delay circuit includes a delay capacitor, and the delay capacitor is electrically connected to an input node between the voltage detection circuit and the voltage monitoring circuit.

[0031] In some embodiments of the present application, the energy transfer circuit includes:

[0032] An energy processing circuit, electrically connected to the energy absorption circuit and the front-end energy storage circuit respectively;

[0033] The transfer control circuit is electrically connected to the energy control circuit and the energy processing circuit, respectively, and is configured to respond to a first start signal transmitted by the energy control circuit to control the energy processing circuit to receive energy released by the energy absorption circuit, or respond to a first stop signal transmitted by the energy control circuit to control the energy processing circuit to stop receiving energy released by the energy absorption circuit. In the stopped state, the energy processing circuit transmits the received energy back to the front-end energy storage circuit for storage.

[0034] In some embodiments of the present application, the energy processing circuit includes:

[0035] An energy storage transfer unit, electrically connected to the front-end energy storage circuit;

[0036] The first switch unit is electrically connected to the energy absorption circuit and the transfer control circuit, respectively, and is configured to respond to a second start signal transmitted by the transfer control circuit to enter an on state, so that the energy released by the energy absorption circuit flows to the energy storage transfer unit through the first switch unit for storage, or, respond to a second stop signal transmitted by the transfer control circuit to enter an off state to block the energy released by the energy absorption circuit from flowing to the energy storage transfer unit through the first switch unit for storage, and to enable the energy storage transfer unit to transfer the stored energy to the front-end energy storage circuit.

[0037] In some embodiments of the present application, the first switching unit includes a first switching tube, which is electrically connected to the energy absorption circuit, the transfer control circuit and the energy storage transfer unit, respectively, and is configured to enter an on state in response to the second start signal, or to enter an off state in response to the second stop signal.

[0038] In some embodiments of the present application, the energy storage transfer unit includes:

[0039] an energy storage inductor, one end of which is electrically connected to the first switch unit, and the other end of which is electrically connected to the front-end energy storage circuit;

[0040] A first unidirectional conduction circuit, one end of the first unidirectional conduction circuit is electrically connected to one end of the energy storage inductor, the other end of the first unidirectional conduction circuit is grounded together with the ground end of the front-end energy storage circuit, and the first unidirectional conduction circuit is configured so that when the first switch unit enters the off state, the current flowing through the energy storage inductor can flow back to the front-end energy storage circuit through the first unidirectional conduction circuit.

[0041] In some embodiments of the present application, the transfer control circuit includes:

[0042] A second switch unit, electrically connected to the energy control circuit, and configured to enter an on state in response to the first start signal, or enter an off state in response to the first stop signal;

[0043] The voltage divider unit is electrically connected to the third node, the energy processing circuit and the second switch unit, respectively, and is configured to respond to the second switch unit entering the on state by converting the voltage at the third node into a second start signal, so that the energy processing circuit responds to the second start signal and receives the energy released by the energy absorption circuit, or, respond to the second switch unit entering the off state, convert the voltage across the energy absorption circuit into a second stop signal, so that the energy processing circuit responds to the second stop signal and stops receiving the energy released by the energy absorption circuit.

[0044] In some embodiments of the present application, the second switching unit includes a second switching tube, which is electrically connected to the energy control circuit and the voltage divider unit, respectively, and is configured to enter an on state in response to the first start signal, or to enter an off state in response to the first stop signal.

[0045] In some embodiments of the present application, the energy absorption circuit includes:

[0046] Absorption unit;

[0047] A second unidirectional conducting circuit is electrically connected between the second node and the third node, and the second unidirectional conducting circuit is configured so that when the switching circuit enters the off state, the current flowing through the primary coil can flow back to the absorption unit through the second unidirectional conducting circuit for storage.

[0048] In some embodiments of the present application, the absorption unit is electrically connected between the first node and the third node; or,

[0049] The absorption unit is electrically connected between the third node and a ground terminal.

[0050] In some embodiments of the present application, the absorption unit is a first capacitor.

[0051] In some embodiments of the present application, the front-end energy storage circuit is a second capacitor, one end of the second capacitor is electrically connected to the first node, and the other end of the second capacitor is grounded.

[0052] In some embodiments of the present application, the switching circuit includes a main switching tube, which is electrically connected to the primary coil and also electrically connected to the controller, and is configured to respond to a conduction signal sent by the controller to enter an on state, or respond to an off state in response to an off signal sent by the controller.

[0053] In some embodiments of the present application, the transformer operates in a flyback mode or a forward mode.

[0054] In a second aspect, an embodiment of the present application provides an electrical device, comprising the energy recovery circuit as described above.

[0055] Compared with the prior art, the energy recovery circuit of the embodiment of the present application includes a front-end energy storage circuit, a switch circuit, a controller, a transformer, an energy absorption circuit, an energy transfer circuit and an energy control circuit, wherein the controller controls the switch circuit to enter an on state or an off state, and the primary coil responds to the switch circuit entering an on state or an off state, and transfers energy to the secondary coil based on the current output by the front-end energy storage circuit. When the switch circuit enters the off state, the energy absorption circuit absorbs the current flowing through the primary coil for storage. And the energy control circuit controls the energy transfer circuit to transfer the energy released by the energy absorption circuit, so that the received energy is transferred to the front-end energy storage circuit for storage, thereby completing energy recovery. Therefore, when the switch circuit of the energy recovery circuit enters the off state, the energy absorption circuit can absorb the peak voltage formed on the switch circuit by the current flowing through the primary coil, and perform high voltage protection on the switch circuit, and the energy recovery circuit also uses the energy transfer circuit to transfer the energy absorbed by the energy absorption circuit to the front-end energy storage circuit for storage, so that the recovered energy continues to be transferred to the secondary coil, thereby improving the conversion efficiency of the power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] One or more embodiments are exemplarily described by the figures in the corresponding drawings, and these exemplary descriptions are not intended to limit the embodiments. Elements with the same reference numerals in the drawings represent similar elements.

[0057] Figure 1 It is a structural schematic diagram of one of the power supply systems provided in the embodiments of the present application;

[0058] Figure 2 is a structural schematic diagram of one of the energy recovery circuits provided in the embodiments of the present application;

[0059] Figure 3 is a structural schematic diagram of one of the energy absorption circuits provided in the embodiments of the present application;

[0060] Figure 4 is a structural schematic diagram of one of the energy control circuits provided in the embodiments of the present application;

[0061] Figure 5 is a structural schematic diagram of one of the energy control circuits provided in the embodiments of the present application;

[0062] Figure 6is a structural schematic diagram of one of the energy control circuits provided in the embodiments of the present application;

[0063] Figure 7 is a structural schematic diagram of one of the energy transfer circuits provided in the embodiments of the present application;

[0064] Figure 8 is a structural schematic diagram of one of the energy transfer circuits provided in the embodiments of the present application;

[0065] Fig. 9 is a structural schematic diagram of one of the energy transfer circuits provided in the embodiments of the present application;

[0066] Fig.10 is a schematic diagram of a circuit structure of an energy recovery circuit provided in an embodiment of the present application;

[0067] Fig.11 is a schematic diagram of a circuit structure of an energy recovery circuit provided in an embodiment of the present application;

[0068] Fig.12 is a schematic diagram of a circuit structure of an energy recovery circuit provided in an embodiment of the present application;

[0069] Fig.13 It is a circuit structure diagram of one of the energy recovery circuits provided in the embodiments of the present application. DETAILED DESCRIPTION

[0070] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and in detail in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0071] In the present application, when an element is expressed as being “connected to” another element, it may be directly connected to the other element, or one or more intervening elements may be present therebetween.

[0072] In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as there is no structural conflict between them.

[0073] See also Figure 1 , Figure 1 Schematic diagram of the structure of an electrical device provided in an embodiment of the present application. Figure 1 As shown, the electrical device includes an energy recovery circuit 100 , a power source 200 and a load 300 .

[0074] The power supply 200 is connected to the energy recovery circuit 100 to provide power for the energy recovery circuit 100. The power supply 200 can be a DC power supply or an AC power supply. When the power supply 200 is an AC power supply, it provides DC power to the energy recovery circuit 100 after rectification and filtering. In addition, the power supply 200 can be a power supply circuit composed of any suitable discrete components. For example, in some embodiments, the power supply 200 is a power supply circuit composed of a filtering circuit, a rectifying circuit, and a voltage stabilizing circuit. For another example, in some embodiments, the power supply 200 is an integrated power chip.

[0075] The energy recovery circuit 100 processes the power provided by the power supply 200 to obtain a secondary voltage signal, the voltage of which is an output voltage. The output voltage may be a high voltage signal or a safety voltage, such as 24V or 36V.

[0076] The energy recovery circuit 100 is connected to the load 300 and provides an output voltage to the load 300 . The load 300 implements corresponding load control logic according to the driving of the secondary voltage signal.

[0077] like Figure 2 As shown, the energy recovery circuit 100 includes a front-end energy storage circuit 1, a switch circuit 2, a controller 3, an energy absorption circuit 4, a transformer 5, an energy transfer circuit 6 and an energy control circuit 7, wherein the transformer 5 includes a coupled primary coil L1 and a secondary coil L2. The grounding end is point a, the front-end energy storage circuit 1 includes a first node point b, the switch circuit includes a second node point c, wherein the primary coil L1 is electrically connected between the first node point b and the second node point c, the switch circuit 2 is electrically connected to the second node point c, the energy absorption circuit 4 is electrically connected between the first node point b and the second node point c, and the switch circuit 2 is also electrically connected to the controller 3. The energy transfer circuit 6 is electrically connected to the third node point d of the energy absorption circuit 4, the energy transfer circuit 6 is also electrically connected to the front-end energy storage circuit 1 at the first node point b, and the energy control circuit 7 is electrically connected to the energy transfer circuit 6.

[0078] The front-end energy storage circuit 1 stores energy, specifically the electrical energy of the power supply 200. The controller 3 controls the switch circuit 2 to enter the on state or the off state. The working state of the switch circuit 2 controls the energy coupling between the primary coil L1 and the secondary coil L2. The energy on the front-end energy storage circuit 1 is converted into a secondary isolated power supply through the coupling of the primary coil L1 and the secondary coil L2, and acts on the load 300.

[0079] Specifically, if the energy recovery circuit 100 is a forward switching power supply, the controller 3 controls the switching circuit 2 to enter the on state, and the current output by the front-end energy storage circuit 1 flows through the primary coil L1. Through the alternating conversion of the electromagnetic field, the electric energy flowing through the primary coil L1 is coupled to the secondary coil L2, and the secondary coil L2 generates an induced voltage to transfer energy to the load circuit.

[0080] The controller 3 then controls the switch circuit 2 to enter the off state, and the current of the primary coil L1 cannot return to zero instantly, and there is a process of decreasing from the maximum to zero. Since the current of the primary coil L1 is suddenly cut off, the current changes abruptly, causing a spike voltage to be generated at both ends of the primary coil L1. Therefore, at the moment when the switch circuit 2 is turned off, the voltage across the switch circuit 2 is the sum of a transient spike voltage and the voltage of the primary coil L1. At the same time, after the switch circuit 2 is turned off, part of the energy corresponding to the freewheeling current of the primary coil L1 needs to be processed, such as being absorbed or consumed.

[0081] If the energy recovery circuit 100 is a flyback switching power supply, the controller 3 controls the switch circuit 2 to enter the on state, and the current output by the front-end energy storage circuit 1 flows through the primary coil L1 to store energy in the primary coil L1. The controller 3 then controls the switch circuit 2 to enter the off state, and the energy stored in the primary coil L1 is coupled to the secondary coil L2 to transfer energy to the secondary coil L2. Similar to the forward switching power supply, at the moment when the switch circuit 2 is turned off, the voltage across the switch circuit 2 is the sum of a transient spike voltage and the voltage of the primary coil L1. At the same time, after the switch circuit 2 is turned off, a portion of the energy corresponding to the freewheeling current of the primary coil L1 needs to be processed, such as being absorbed or consumed.

[0082] In some embodiments, the controller 3 is a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a single-chip microcomputer, an ARM (Acorn RISC Machine) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or a combination of these components.

[0083] In order to prevent the switch circuit 2 from being impacted by the transient spike voltage after being turned off, and to effectively utilize the energy contained in the freewheeling current, the energy recovery circuit 100 further includes an energy absorption circuit 4, which is electrically connected between the second node c and the first node b, or between the second node c and the ground point a. The energy absorption circuit 4 absorbs the freewheeling current flowing through the primary coil L1 and the energy contained therein for storage, and clamps the voltage to which the switch circuit 2 is subjected after being turned off, so as to protect the switch circuit 2. The energy absorption circuit 4 is composed of a unidirectional conduction circuit and a capacitor of microfarad level or above.

[0084] Please continue reading Figure 2 When the switch circuit 2 enters the off state, the energy absorption circuit 4 absorbs the current flowing through the primary coil L1 and the energy contained therein for storage to obtain the first energy, while preventing the switch circuit 2 from being impacted by the peak high voltage at the moment of shutdown, thereby protecting the switch circuit 2.

[0085] In order to fully utilize the energy absorbed by the energy absorption circuit, the energy control circuit 7 controls the energy transfer circuit 6 to transfer the energy absorbed by the energy absorption circuit 4 to the front-end energy storage circuit 1 for storage.

[0086] Specifically, as the first energy stored in the energy absorption circuit 4 increases, when the energy control circuit 7 detects that the first energy stored in the energy absorption circuit 4 is greater than the preset energy, the energy control circuit 7 sends a first start signal to control the energy transfer circuit 6 to receive the energy released by the energy absorption circuit 4 and store it.

[0087] As the amount of the first energy released by the energy absorption circuit 4 increases, when the energy control circuit 7 detects that the remaining first energy of the energy absorption circuit 4 is less than the preset energy, the energy control circuit 7 sends a first stop signal to control the energy transfer circuit 6 to stop receiving the energy released by the energy absorption circuit 4, and the energy absorption circuit 4 can no longer release energy to the energy transfer circuit 6 through the third node d.

[0088] At the same time, the energy transfer circuit 6 transmits the received energy back to the front-end energy storage circuit 1 for storage. For example, if the first energy is E1 and the recovered energy is the second energy E2, the energy transfer circuit 6 transfers the second energy E2 to the front-end energy storage circuit 1 for storage, and the difference between the first energy E1 and the second energy E2 is the remaining energy of the energy absorption circuit 4.

[0089] The front-end energy storage circuit 1 stores the second energy E2. When the switch circuit 2 enters the next on state or off state, the front-end energy storage circuit 1 continues to transfer the second energy E2 to the secondary coil L2 through the coupling between the primary coil L1 and the secondary coil L2, thereby supplying power to the load 300.

[0090] Therefore, in the embodiment of the present application, the energy absorption circuit 4 absorbs the peak voltage formed on the switch circuit 2 by the current flowing through the primary coil L1, and performs high voltage protection on the switch circuit 2. Moreover, the energy absorbed by the energy absorption circuit 4 is not consumed, but the energy released by the energy absorption circuit 4 is received by the energy transfer circuit 6 and transmitted back to the front-end energy storage circuit 1, so that the recovered energy continues to be transmitted to the secondary coil L2 through coupling, and is reused, thereby improving the conversion efficiency of the power supply, thereby reducing the temperature rise of the system and improving the system reliability.

[0091] In some embodiments, Figure 3 As shown, the energy absorption circuit 4 includes an absorption unit 42 and a second unidirectional conduction circuit 41, wherein the second unidirectional conduction circuit 41 is electrically connected between the second node c and the third node d, and the absorption unit 42 is electrically connected between the first node b and the third node d, or the absorption unit 42 is electrically connected between the third node d and the ground. Figure 4In the figure, it is taken as an example that the absorption unit 42 is electrically connected between the third node d and the first node b.

[0092] When the switch circuit 2 enters the off state, the primary coil L1, the second unidirectional conduction circuit 41 and the absorption unit 42 form a loop, and the current flowing through the primary coil L1 flows back to the absorption unit 42 through the second unidirectional conduction circuit 41 for storage. The direction of the current is: primary coil L1→second unidirectional conduction circuit 41→absorption unit 42.

[0093] The second unidirectional conduction circuit 41 can be implemented by means of a synchronous rectification circuit, a diode, a field effect transistor, a unidirectional conduction thyristor, etc. The absorption unit 42 is a circuit that can store energy, which can be implemented by means of a capacitor, a battery, etc.

[0094] In some embodiments, Figure 4 As shown, the energy control circuit 7 includes a voltage stabilization control circuit 71, wherein the voltage stabilization control circuit 71 is electrically connected to the energy absorption circuit 4 and the energy transfer circuit 6 respectively.

[0095] When the voltage stabilizing control circuit 71 detects that the first energy of the energy absorbing circuit 4 is greater than the preset energy, the voltage stabilizing control circuit 71 sends a first start signal to control the energy transfer circuit 6 to transfer the energy absorbed by the energy absorbing circuit 4 and transfer the absorbed energy to the front-end energy storage circuit 1. As the transfer occurs, the energy of the energy absorbing circuit 4 will become lower and lower. When the voltage stabilizing control circuit 71 detects that the remaining first energy of the energy absorbing circuit 4 is less than the preset energy, the voltage stabilizing control circuit 71 sends a first stop signal to control the energy transfer circuit 6 to stop transferring the energy absorbed by the energy absorbing circuit 4.

[0096] Therefore, the energy transfer circuit 6 can control the energy of the energy absorption circuit 4 to make it fluctuate within a small range, so that the voltage across it is equivalent to being in a stable voltage state. After the switch circuit 2 is turned off, the voltage across the primary coil L1 is the same as the voltage across the energy absorption circuit 4, which is equivalent to the voltage across the primary coil L1 being in a stable voltage state, thereby making the current flowing through the primary coil L1 drop evenly, and the magnetic flux in the magnetic circuit of the transformer 5 changes evenly, so that the output voltage at the secondary coil L2 remains stable.

[0097] The voltage at the third node d reflects the voltage across the energy absorption circuit 4 in real time. Therefore, in the embodiment of the present application, a voltage detection circuit is used to detect the voltage at the third node d.

[0098] Specifically, Figure 4As shown, the voltage stabilization control circuit 71 includes a voltage detection circuit 711 and a voltage monitoring circuit 712, wherein the voltage detection circuit 711 is electrically connected to the energy absorption circuit 4, and the voltage monitoring circuit 712 is electrically connected to the voltage detection circuit 711 and the energy transfer circuit 6 respectively.

[0099] The voltage detection circuit 711 is electrically connected between the third node d and the first node b. The voltage detection circuit 711 detects the voltage across the energy absorption circuit 4 to obtain a sampled voltage, and transmits the sampled voltage to the voltage monitoring circuit 712. The voltage monitoring circuit 712 controls the working state of the energy transfer circuit 6 based on the sampled voltage.

[0100] When the energy absorption circuit 4 absorbs more and more energy, the voltage across the energy absorption circuit 4 becomes higher and higher, and the voltage value of the sampling voltage becomes higher and higher. When the sampling voltage is greater than the preset reference voltage, the voltage monitoring circuit 712 controls the energy transfer circuit 6 to start recovering and transferring the energy absorbed by the energy absorption circuit 4. The sampling voltage signal greater than the preset reference voltage is the first trigger signal in the above embodiment.

[0101] As the energy is transferred, the energy of the energy absorption circuit 4 becomes lower and lower, and the voltage across the energy absorption circuit 4 becomes lower and lower. When the sampled voltage is less than or equal to the preset reference voltage, the voltage monitoring circuit 712 controls the energy transfer circuit 6 to stop transferring the energy released by the energy absorption circuit 4. The sampled voltage signal less than or equal to the preset reference voltage is the second trigger signal in the above embodiment.

[0102] Therefore, the embodiment of the present application monitors the voltage across the energy absorption circuit 4 in real time through the voltage detection circuit 711 to control the energy of the energy absorption circuit 4. When the voltage across the energy absorption circuit 4 is high, the voltage monitoring circuit 712 controls the energy transfer circuit 6 to transfer the energy of the energy absorption circuit 4. The voltage detection circuit 711 and the voltage monitoring circuit 712 can effectively control the process of energy transfer of the energy transfer circuit 6.

[0103] In the above embodiment, when the voltage across the energy absorption circuit 4 changes, the sampling voltage reflects the change of the voltage across the energy absorption circuit 4 in real time, and the sampling voltage follows the voltage across the energy absorption circuit 4 to increase or decrease in real time, so that the voltage monitoring circuit 712 follows the increase or decrease of the sampling voltage, responds in real time, and controls the energy transfer circuit 6 to enter the working state or the stop working state.

[0104] However, this may cause the working state of the energy transfer circuit 6 to change too frequently. For example, if the voltage across the energy absorption circuit 4 is V1, the sampled voltage is greater than the preset reference voltage, but the difference between the sampled voltage and the preset reference voltage is very small, but it is enough to keep the energy transfer circuit 6 in the working state, and the energy transfer circuit 6 recovers the energy of the energy absorption circuit 4 normally. When the voltage across the energy absorption circuit 4 changes slightly and drops to V2, the sampled voltage reflects the slight change in real time. The slight change makes the sampled voltage less than the preset reference voltage, and the voltage monitoring circuit 712 is triggered by the sampled voltage, thereby controlling the energy transfer circuit 6 to enter the stop working state. Similarly, if the voltage across the energy absorption circuit 4 changes slightly again at this time and rises to V3, the slight change is again reflected in the sampled voltage in real time. If the sampled voltage is greater than the preset reference voltage again, the voltage monitoring circuit 712 is triggered by the sampled voltage, thereby controlling the energy transfer circuit 6 to enter the working state again.

[0105] If the sampling voltage responds to the voltage across the energy transfer circuit 6 in real time, the voltage monitoring circuit 712 may be triggered frequently and the working state of the energy transfer circuit 6 may be changed frequently. This may cause frequent responses to some false triggering events, increase the loss of the voltage monitoring circuit 712 and the energy transfer circuit 6, and even cause the temperature of components to rise or be damaged.

[0106] For the reasons above, please continue to read Figure 4 In an embodiment of the present application, the energy control circuit 7 also includes a delay circuit 72, wherein the delay circuit 72 is electrically connected to an input node between the voltage detection circuit 711 and the voltage monitoring circuit 712, and the delay circuit 72 controls the sampling voltage to lag behind the change of the voltage at both ends of the energy absorption circuit 4.

[0107] In the embodiment of the present application, a delay circuit 72 is used to control the sampling voltage to lag behind the change of the voltage at both ends of the energy absorption circuit 4. When the voltage at both ends of the energy absorption circuit 4 changes between V1 and V2, or changes between V2 and V3, the sampling voltage changes with lag, thereby reducing the frequent triggering of the voltage monitoring circuit 712 and the energy transfer circuit 6, preventing false triggering, and improving the reliability and stability of the system.

[0108] The delay circuit 72 can be implemented in a variety of ways, such as an RC delay circuit, a 555 timer delay circuit or a monostable trigger delay circuit, a transistor delay circuit, an oscillation counter delay circuit, etc.

[0109] In some embodiments, Figure 5As shown, the voltage detection circuit 711 also includes a voltage sampling circuit 7111 and a signal conditioning circuit 7112, wherein the voltage sampling circuit 7111 is electrically connected to the energy absorption circuit 4, and the signal conditioning circuit 7112 is electrically connected to the voltage sampling circuit 7111 and the voltage monitoring circuit 712 respectively.

[0110] In the embodiment of the present application, the first end of the voltage sampling circuit 7111 is electrically connected to the third node d, the second end thereof is electrically connected to the first node b, and the third end thereof is grounded. The output end of the voltage sampling circuit 7111 is also electrically connected to the input end of the signal conditioning circuit 7112, and the output end of the signal conditioning circuit 7112 is electrically connected to the voltage monitoring circuit 712.

[0111] The voltage sampling circuit 7111 detects the voltage across the energy absorption circuit 4 to obtain a sampling voltage, and the sampling voltage is transmitted to the input end of the signal conditioning circuit 7112. The signal conditioning circuit 7112 performs signal conditioning processing on the sampling voltage to obtain a conditioned sampling voltage, so that the voltage monitoring circuit 712 controls the working state of the energy transfer circuit 6 based on the conditioned sampling voltage.

[0112] The voltage sampling circuit 7111 can be implemented in a variety of ways, such as through a resistor voltage divider network or a dedicated sampling element. The signal conditioning circuit 7112 can amplify, filter or isolate the sampled voltage, so that the conditioned sampled voltage is more stable and accurate, and it is convenient for the voltage monitoring circuit 712 to respond to the conditioned sampled voltage.

[0113] In some embodiments, the normal operation of the signal conditioning circuit 7112 requires a working power supply, which can be a separate independent power supply, such as a separate power module or battery, which does not rely on other parts of the system for power supply, and can provide stable voltage and current. The working power supply can also be directly coupled from the primary coil L1, which can reduce the demand for external power supply, simplify circuit design, and reduce circuit cost.

[0114] In the embodiment of the present application, the working power supply is coupled from the primary coil L1, specifically, Figure 5 As shown, the transformer 5 further includes an auxiliary coil L4, which is coupled to the primary coil L1.

[0115] When the switch circuit 2 is in the on state, current flows through the primary coil L1, the primary coil L1 generates a magnetic field, and part of the energy of the primary coil L1 is transferred to the auxiliary coil L4 through coupling, and a coupling voltage is generated on the auxiliary coil L4, wherein the value of the coupling voltage is determined by the turns ratio of the auxiliary coil L4 to the primary coil L1, and the turns ratio of the auxiliary coil L4 to the primary coil L1 is determined based on the working power supply of the signal conditioning circuit 7112.

[0116] In some embodiments, the coupling voltage does not directly supply power to the signal conditioning circuit 7112 , but the coupling voltage needs to be conditioned and the conditioned coupling voltage is used as the working power supply of the signal conditioning circuit 7112 .

[0117] Specifically, the voltage detection circuit 711 also includes a power input circuit 7113, which is electrically connected to the auxiliary coil L4 and the signal conditioning circuit 7112, respectively. The power input circuit 7113 provides working power to the signal conditioning circuit 7112 based on the coupling voltage. The power input circuit 7113 performs voltage stabilization, filtering, and noise removal on the coupling voltage, and uses the processed coupling voltage as the working power of the signal conditioning circuit 7112 to supply power to the signal conditioning circuit 7112. The power processing circuit stabilizes the coupling voltage to reduce voltage fluctuations, and performs noise reduction on the coupling voltage, so that the conditioned coupling voltage is more stable and reliable.

[0118] In some embodiments, see Figure 6 The signal conditioning circuit 7112 is an operational amplifier op1, and the voltage sampling circuit 7111 includes a first voltage sampling branch 71111 and a second voltage sampling branch 71112, wherein the first voltage sampling branch 71111 is electrically connected between the first node b and the ground, and the first voltage sampling branch 71111 includes a fifth node, and the inverting input terminal of the operational amplifier op1 is electrically connected to the fifth node. The second voltage sampling branch 71112 is electrically connected between the third node d and the ground, and the second voltage sampling branch 71112 includes a sixth node, and the non-inverting input terminal of the operational amplifier op1 is electrically connected to the sixth node, and the output terminal of the operational amplifier op1 is electrically connected to the voltage monitoring circuit 712.

[0119] One end of the first voltage sampling branch 71111 connected to the first node b is the second end of the voltage sampling circuit 7111, one end of the second voltage sampling branch 71112 connected to the third node d is the first end of the voltage sampling circuit 7111, and the common grounding end of the first voltage sampling branch 71111 and the second voltage sampling branch 71112 is the third end of the voltage sampling circuit 7111.

[0120] The first voltage sampling branch 71111 samples the voltage at the first node b to obtain a first sampling voltage, the second voltage sampling branch 71112 samples the voltage at the third node d to obtain a second sampling voltage, the operational amplifier op1 differentially amplifies the first sampling voltage and the second sampling voltage to obtain a conditioned sampling voltage, and the voltage monitoring circuit 712 controls the working state of the energy transfer circuit 6 based on the conditioned sampling voltage.

[0121] The first voltage sampling branch 71111 and the second voltage sampling branch 71112 are used to sample the voltage at the first node b and the voltage at the third node d respectively. The conditioned sampling voltage reflects the change in the voltage difference between the first node b and the third node d. The conditioned sampling voltage is obtained by differential amplification, which can eliminate common-mode interference in the first sampling voltage and the second sampling voltage, such as noise or electromagnetic interference in the environment, thereby improving the signal-to-noise ratio of the signal, and can also enhance the difference between the first sampling voltage and the second sampling voltage, so as to more accurately measure the voltage difference between the two nodes, thereby improving the accuracy of the sampling voltage.

[0122] In some embodiments, see Figure 7 , Figure 7 is a schematic diagram of the structure of an energy transfer circuit 6 provided in an embodiment of the present application, such as Figure 7 As shown, the energy transfer circuit 6 includes an energy processing circuit 61 and a transfer control circuit 62, wherein the energy processing circuit 61 is electrically connected to the energy absorption circuit 4 and the front-end energy storage circuit 1 respectively, and the transfer control circuit 62 is electrically connected to the energy control circuit 7 and the energy processing circuit 61 respectively.

[0123] Specifically, the energy processing circuit 61 is electrically connected to the third node d, the front-end energy storage circuit 1, and the transfer control circuit 62. When the switch circuit 2 enters the off state, the energy absorption circuit 4 absorbs the current flowing through the primary coil L1 for storage. When the energy control circuit 7 detects that the first energy absorbed by the energy absorption circuit 4 is greater than the preset energy, the energy control circuit 7 transmits a first start signal to the transfer control circuit 62. The transfer control circuit 62 responds to the first start signal and controls the energy processing circuit 61 to transfer the energy absorbed by the energy absorption circuit 4. The energy of the energy absorption circuit 4 is transferred to the energy processing circuit 61 via the third node d.

[0124] As the energy of the energy absorption circuit 4 is released, when the energy control circuit 7 detects that the first energy absorbed by the energy absorption circuit 4 is less than or equal to the preset energy, the energy control circuit 7 transmits a first stop signal to the transfer control circuit 62, controls the energy processing circuit 61 to stop receiving the energy released by the energy absorption circuit 4, and transmits the received energy back to the front-end energy storage circuit 1 for storage.

[0125] The energy processing circuit 61 recovers the energy released by the energy absorption circuit 4, which can be recovered by storage, that is, the energy processing circuit 61 stores the energy released by the received energy absorption circuit 4, and transmits the stored energy back to the front-end energy storage circuit 1 in a stopped state, so that the front-end energy storage circuit 1 stores the returned energy. For example, if the energy released by the energy absorption circuit 4 is the second energy E2, the energy processing circuit 61 first receives and stores the second energy E2, and in its stopped state, transmits the second energy E2 back to the front-end energy storage circuit 1, and the front-end energy storage circuit 1 stores the second energy E2, and finally recovers the second energy E2 to the front-end energy storage circuit 1 through secondary transfer and secondary storage.

[0126] In some embodiments, see Figure 8 The energy processing circuit 61 includes an energy storage transfer unit 611 and a first switch unit 612, wherein the energy storage transfer unit 611 is electrically connected to the front-end energy storage circuit 1, and the first switch unit 612 is electrically connected to the energy absorption circuit 4 and the transfer control circuit 62 respectively. Specifically, the first switch unit 612 is electrically connected to the third node d and the transfer control circuit 62, and the energy storage transfer unit 611 is electrically connected to the front-end energy storage circuit 1.

[0127] When the transfer control circuit 62 responds to the first start signal, the transfer control circuit 62 transmits the second start signal to the first switch unit 612, the first switch unit 612 enters the on state, and the energy released by the energy absorption circuit 4 flows to the energy storage transfer unit 611 through the third node d and the first switch unit 612, and the energy storage transfer unit 611 stores the released energy. When the transfer control circuit 62 responds to the first stop signal, the transfer control circuit 62 transmits the second stop signal to the first switch unit 612, the first switch unit 612 enters the off state, and then blocks the energy released by the energy absorption circuit 4 from flowing to the energy storage transfer unit 611 through the third node d and the first switch unit 612, that is, the energy absorption circuit 4 can no longer release energy to the energy storage transfer unit 611 through the third node d and the first switch unit 612, or can no longer transfer energy to the energy storage transfer unit 611, or the energy released by the energy absorption circuit 4 can no longer flow to the energy storage transfer unit 611. Furthermore, after the first switch unit 612 enters the off state, the energy stored in the energy storage transfer unit 611 is transmitted back to the front-end energy storage circuit 1 .

[0128] Therefore, in an embodiment of the present application, the energy control circuit 7 sends a first start signal or a first stop signal, and then sends a second start signal or a second stop signal to the control transfer control circuit 62 to control the working state of the first switch unit 612, and then control the energy storage transfer unit 611 to recover or store the energy released by the energy absorption circuit 4.

[0129] In the embodiment of the present application, the energy storage transfer unit 611 stores the energy released by the energy absorption circuit 4, and then transmits the stored energy back to the front-end energy storage circuit 1, so that the front-end energy storage circuit 1 stores the energy released by the energy absorption circuit 4, and the energy is transferred and stored for the second time to realize energy recovery.

[0130] In some embodiments, please refer to Figure 8 The energy storage transfer unit 611 includes an energy storage inductor 6111 and a first unidirectional conduction circuit 6112, wherein one end of the energy storage inductor 6111 is electrically connected to the first switch unit 612, the other end of the energy storage inductor 6111 is electrically connected to the front-end energy storage circuit 1, one end of the first unidirectional conduction circuit 6112 is electrically connected to one end of the energy storage inductor 6111, and the other end of the first unidirectional conduction circuit 6112 is grounded together with the ground end of the front-end energy storage circuit 1. The first unidirectional conduction circuit 6112 can be implemented by a synchronous rectification circuit, a diode, a field effect transistor, a unidirectional conduction thyristor, and the like.

[0131] When the first switch unit 612 is in the on state, the energy of the energy absorption circuit 4 flows to the energy storage inductor 6111 via the third node d and the first switch unit 612, and the energy storage inductor 6111 stores the energy released by the energy absorption circuit 4. When the first switch unit 612 is in the off state, the energy of the energy absorption circuit 4 stops flowing to the energy storage inductor 6111, and at the same time, the energy stored in the energy storage inductor 6111 flows back to the front-end energy storage circuit 1 via the first unidirectional conduction circuit 6112, that is, the energy stored in the energy storage inductor 6111 is transmitted back to the front-end energy storage circuit 1 for storage.

[0132] In the embodiment of the present application, the energy released by the energy absorption circuit 4 is first transferred to the energy storage inductor 6111, and then transferred to the front-end energy storage circuit 1 through the energy storage inductor 6111. The energy released by the energy absorption circuit 4 is transferred and stored twice to achieve energy recovery.

[0133] In some embodiments, Fig. 9 As shown, the transfer control circuit 62 includes a second switch unit 621 and a voltage divider unit 622, wherein the second switch unit 621 is electrically connected to the energy control circuit 7, and the voltage divider unit 622 is electrically connected to the energy absorption circuit 4, the energy processing circuit 61 and the second switch unit 621, respectively. Specifically, the voltage divider unit 622 is electrically connected to the third node d, the energy processing circuit 61 and the second switch unit 621, respectively.

[0134] When the energy control circuit 7 sends a first start signal to the second switch unit 621, the second switch unit 621 is in an on state, the voltage divider unit 622 divides the voltage at the third node and generates a voltage divider signal, which is a second start signal. The second start signal is transmitted to the energy processing circuit 61, and the energy processing circuit 61 responds to the second start signal to recover the energy released by the energy absorption circuit 4.

[0135] When the energy control circuit 7 sends a first stop signal to the second switch unit 621, the second switch unit 621 enters an off state, and the voltage divider unit 622 responds to the second switch unit 621 entering the off state, converts the voltage across the energy absorption circuit 4 into a second stop signal, and the energy processing circuit 61 responds to the second stop signal to stop recovering the energy released by the energy absorption circuit 4.

[0136] In an embodiment of the present application, the energy control circuit 7 controls the working state of the second switch unit 621 through a first start signal and a first stop signal, and then controls the second switch unit 621 to send a second start signal or a second stop signal to the energy processing circuit 61 to control the energy processing circuit 61 to be in a recovery state or stop the recovery state.

[0137] See also Fig.10 , Fig.10 is a schematic diagram of a circuit structure of an energy recovery circuit provided in an embodiment of the present application, such as Fig.10 As shown, the transformer 5 is the transformer T1, the absorption unit 42 is the first capacitor C2, the front-end energy storage circuit 1 is the second capacitor C0, one end of the second capacitor C0 is electrically connected to the first node b, and the other end of the second capacitor C0 is grounded, wherein the capacitance value of the first capacitor C2 is greater than or equal to the microfarad level.

[0138] The second unidirectional conduction circuit 41 is a diode D1, the anode of the diode D1 is electrically connected to the second node c, the cathode of the diode D1 and one end of the first capacitor C2 are electrically connected to the third node d, and the other end of the first capacitor C2 is electrically connected to the first node b, wherein one end of the first capacitor C2 can be its positive electrode, and the other end of the first capacitor C2 can be its negative electrode.

[0139] The switch circuit 2 includes a main switch tube G1, which is a MOS tube. The drain of the main switch tube G1 is electrically connected to the primary coil L1 at the second node c, the gate of the main switch tube G1 is connected to the controller 3, and the source of the main switch tube G1 is grounded.

[0140] The controller 3 sends a conduction signal to the gate of the main switch tube G1, and the main switch tube G1 enters the conduction state. The controller 3 sends an off signal to the gate of the main switch tube G1, and the main switch tube G1 enters the off state. The working state of the main switch tube G1 controls the energy coupling between the primary coil L1 and the secondary coil L2.

[0141] The second capacitor C0 is used to store the electric energy of the power supply. The electric energy stored in the second capacitor C0 is transmitted to the secondary coil L2 through the coupling between the primary coil L1 and the secondary coil L2, and then supplies power to the load.

[0142] When the main switch G1 is turned off, the current flowing through the primary coil L1 is I 12 , the voltage in the primary coil L1 is U 12 , the current I flowing through the primary coil L1 12 The current flows through the diode D1 to the first capacitor C2, and the first capacitor C2 absorbs the current flowing through the primary coil L1 for storage, clamps the switch voltage of the main switch tube G1, prevents it from being impacted by the peak high voltage, and protects the main switch tube G1. After the power supply is started, the first capacitor C2 continuously absorbs the energy E12 in the primary coil L1 after the main switch tube G1 is turned off, and stores it to form energy Ec2. As the energy EC2 absorbed and stored by the first capacitor C2 increases, the voltage Udb across the first capacitor C2 increases with the increase of energy EC2.

[0143] Please continue reading Fig.10 The voltage detection circuit 711 includes a resistor R4 and a resistor R5, the voltage monitoring circuit 712 is a voltage monitor U1, pin 1 of the voltage monitor U1 is an e-node, pin 2 of the voltage monitor U1 is a g-node, and pin 3 of the voltage monitor U1 is connected to a b-node.

[0144] The delay circuit 72 is a capacitor C3, wherein resistors R4 and R5 are connected in series between a third node d and a first node b, a common connection end of resistors R4 and R5 is respectively connected to pin 1 of the voltage monitor U1 and one end of capacitor C3, the other end of capacitor C3 and pin 3 of the voltage monitor U1 are commonly connected to the first node b, and pin 2 of the voltage monitor U1 is electrically connected to the energy transfer circuit 6.

[0145] The first switch unit 612 includes a first switch tube G2, the second switch unit 621 includes a second switch tube G3, the voltage divider unit 622 includes a resistor R2 and a resistor R3, the energy storage inductor 6111 is an inductor L3, and the first unidirectional conduction circuit 6112 is a diode D2.

[0146] The gate of the second switch tube G3 is connected to pin 2 of the voltage monitor U1, the source of the second switch tube G3 is connected to the first node b, the resistor R2 and the resistor R3 are connected in series between the third node d and the drain of the second switch tube G3, the common connection end of the resistor R2 and the resistor R3 is the node i, which is connected to the gate of the first switch tube G2, the source of the first switch tube G2 is connected to the third node d, the drain of the first switch tube G2 is respectively connected to one end of the inductor L3 and the cathode of the diode D2 at point h, the other end of the inductor L3 is connected to the first node b, and the anode of the diode D2 is grounded.

[0147] Resistors R4 and R5 divide the voltage across the first capacitor C2 to generate a voltage Ueb at pin 1 of the voltage monitor U1. The voltage Ueb is also the voltage across the capacitor C3. The voltage Ueb increases as the voltage across the first capacitor C2 increases. Since the capacitor C3 has a delay effect, the increase process of the voltage Ueb lags behind the increase process of the voltage across the first capacitor C2.

[0148] When Udb increases to ((R4+R5)÷R5)×Vref (threshold voltage of voltage monitor U1), Ueb is still lower than Vref. Only when Udb increases to a certain value (specifically defined as Udb0 here), Ueb will increase to Vref.

[0149] When the voltage Udb across the first capacitor C2 continues to increase until the voltage Ueb is equal to the threshold voltage Vref of the voltage monitor U1, the voltage monitor U1 outputs a high level, that is, the voltage Ugb between the g node and the b node is a high level.

[0150] The high level voltage Ugb drives the second switch tube G3 to turn on. At this time, the voltage Udb generates a voltage drop Udi on the resistor R2. Udi drives the first switch tube G2 to turn on. At this time, the first capacitor C2 absorbs the stored energy Ec2 and transfers it to the inductor L3 through the first switch tube G2. The current in the inductor L3 (here defined as I L3 ) gradually increases from 0.

[0151] As the energy Ec2 is transferred to the inductor L3 through the first switch tube G2, the voltage Udb of the first capacitor C2 will decrease. As the voltage Udb decreases, the voltage Ueb across the capacitor C3 will also decrease, but due to the blocking effect of the resistor R4 and the resistor R5, the voltage reduction process of the voltage Ueb across the capacitor C3 lags behind the reduction process of the voltage Udb across the first capacitor C2. When Udb decreases to equal ((R4+R5)÷R5)×Vref (the threshold voltage of the voltage monitor U1), Ueb is still higher than Vref. At this time, the voltage monitor U1 still outputs a high level, and the energy Ec2 continues to be transferred to the inductor L3 through the first switch tube G2. Only when Udb continues to decrease to below a certain value (the value is specifically defined as Udb1 here), Ueb will be reduced to equal Vref. As the voltage Udb continues to decrease, Ueb will decrease to slightly below Vref, and the voltage monitor U1 will output a low level, that is, the voltage Ugb between the g node and the b node is almost 0, and the second switch tube G3 is turned off.

[0152] After the second switch tube G3 is turned off, the voltage Udb generates a voltage drop Ud i of 0 on the resistor R2, and the first switch tube G2 is turned off. At this time, the first capacitor C2 absorbs the stored energy Ec2 and stops transferring it to the inductor L3 through the first switch tube G2 (herein, the energy stored in C2 and transferred to the inductor L3 is defined as Ec2). L3 ), the current I in inductor L3 L3 reaches the maximum (here the maximum current is defined as I L31 ).

[0153] Due to the freewheeling characteristics of the inductor L3, after the first switch tube G2 is turned off, the inductor L3 drives the current I L3 The current I flows into the second capacitor C0 through the loop formed by the inductor L3, the diode D2 and the second capacitor C0. Before the first switch G2 is turned on again, the current I L3 By the maximum current I L31 At the same time, the energy E transferred from the first capacitor C2 received by the inductor L3 L3 The second capacitor C0 is transferred to the primary coil L1 after the switch tube G1 is turned off. 12 , U 12 The energy E 12 of recycling.

[0154] I in the primary coil L1 12 , U 12 The energy E 12 After the secondary transfer, the secondary storage is transferred to the second capacitor C0, so that the recovered energy continues to be transferred to the secondary coil L2 through coupling, thereby improving the conversion efficiency of the power supply.

[0155] In the embodiments of the present application, energy-consuming components are removed, so that the internal heat of the power supply is greatly reduced, the temperature rise of the power supply is greatly reduced, the influence of the temperature rise on the power supply components is greatly reduced, the reliability of the components is greatly improved, the working time of the components is greatly improved, and the reliability of the power supply is greatly improved.

[0156] Moreover, due to the delay effect of capacitor C3, the change of Ueb lags behind the change of Udb. The switch control process of the second switch tube G3 output by the voltage monitor U1 has a hysteresis process. During this hysteresis process, the voltage Udb across the first capacitor C2 fluctuates between Udb0 and Udb1, but is basically stable at the value of ((R4+R5)÷R5)×Vref.

[0157] Therefore, the voltage Udb across the first capacitor C2 is equivalent to being in a voltage-stabilizing state, and is stabilized at a fixed value ((R4+R5)÷R5)×Vref (with ripples). Then the voltage Udb across the first capacitor C2 is stabilized at a fixed value, so that after the switch tube G1 is turned off, the current I 12 The voltage U in the primary coil L1 decreases evenly from the maximum value to 0. 12 At the current I 12 The current I 12 When it returns to 0, it returns to 0. The current I in the primary coil L1 12 The uniform change of makes the magnetic flux in the magnetic circuit of transformer T1 change uniformly, so that the output voltage of secondary coil L2 remains stable.

[0158] It should be noted that, except for the first capacitor C1 and the inductor L3, all other components in the energy absorption circuit 4, the energy control circuit 7 and the energy transfer circuit 6 can be integrated into one chip, or integrated with the controller 3 to form one chip.

[0159] See also Fig.11 , Fig.11 is a schematic diagram of a circuit structure of an energy recovery circuit provided in an embodiment of the present application, such as Fig.11 As shown, the embodiments of the present application are Fig.10 The difference of the embodiment shown is that the negative electrode of the first capacitor C2 is grounded, and the connection and working principle of other components are the same as Fig.11 The embodiments shown are the same and will not be described again.

[0160] See also Fig.12 , Fig.12 is a schematic diagram of a circuit structure of an energy recovery circuit provided in an embodiment of the present application, such as Fig.12 As shown, the embodiments of the present application are Fig.10The difference of the embodiment shown is that the resistor R3 is replaced by a voltage stabilizing element D3, the cathode of the voltage stabilizing element is connected to the node i, the anode of the voltage stabilizing element D3 is connected to the drain of the second switch tube G3, and the connection and working principle of other components are the same as Fig.11 The embodiments shown are the same and will not be described again.

[0161] In the embodiment of the present application, due to the voltage stabilizing effect of the voltage stabilizing element D3, the parameter selection of the resistor R2 is more flexible, and the second switch tube G3 obtains a more stable driving voltage.

[0162] See also Fig.13 , Fig.13 is a schematic diagram of a circuit structure of an energy recovery circuit provided in an embodiment of the present application, such as Fig.13 As shown, the embodiments of the present application are Fig.10 The difference of the illustrated embodiment is that the voltage detection circuit 711 includes a voltage sampling circuit 7111 and a signal conditioning circuit 7112 , wherein the voltage sampling circuit 7111 includes a first voltage sampling branch 71111 and a second voltage sampling branch 71112 .

[0163] The first voltage sampling branch 71111 includes a resistor R6 and a resistor R7, the second voltage sampling branch 71112 includes a resistor R4 and a resistor R5, and the signal conditioning circuit 7112 includes an operational amplifier op1, and resistors R8 to R11. Among them, the resistor R4 and the resistor R5 are connected in series between the third node d and the ground, the resistor R4, the resistor R5, the capacitor C3 and one end of the resistor R10 are connected to the e node, the resistor R6 and the resistor R7 are connected in series between the first node b and the ground, the resistor R6, the resistor R7 and one end of the resistor R9 are connected to the f node, the other end of the resistor R9 is respectively connected to the inverting input terminal of the operational amplifier op1 and one end of the resistor R8, the other end of the resistor R10 is respectively connected to the non-inverting input terminal of the operational amplifier op1 and one end of the resistor R11, the other end of the resistor R8 is respectively connected to the output terminal of the operational amplifier op1 and the 1 pin of the voltage monitor U1, the other end of the resistor R11 is grounded, and the 3 pin of the voltage monitor U1 is grounded. And the source of the second switch tube G3 is no longer connected to the first node b, but is grounded.

[0164] Therefore, in the embodiment of the present application, the voltage reference point of the voltage sampling circuit 7111 is the ground. At the same time, in the embodiment of the present application, the operating power is provided to the operational amplifier op1 through the auxiliary coil L4 and the power input circuit 7113.

[0165] Specifically, the transformer T1 also includes an auxiliary coil L4, which is coupled to the primary coil L1. The power input circuit 7113 includes a Schottky diode D3, a Schottky diode D4, a capacitor C4 and a capacitor C5, wherein one end of the auxiliary coil L4 is connected to the anode of the regulator D3 and the anode of the regulator D4 respectively, the other end of the auxiliary coil L4 is grounded, the cathode of the regulator D3 is connected to one end of the capacitor C4, the other end of the capacitor C4 is grounded, the cathode of the regulator D4 is connected to one end of the capacitor C5, and the other end of the capacitor C5 is grounded.

[0166] When the switch tube G1 is in the on state, current flows through the primary coil L1, the primary coil L1 generates a magnetic field, and part of the energy of the primary coil L1 is transferred to the auxiliary coil L4 through coupling, and a coupling voltage is generated on the auxiliary coil L4.

[0167] After being stabilized by the stabilizers D3 and D4 and filtered by the capacitors C4 and C5, the coupling voltage is converted into a power supply for the operational amplifier op1, which supplies power to the operational amplifier op1 and enables it to work normally.

[0168] Resistors R4 and R5 divide the voltage at the third node d to obtain a first sampling voltage, resistors R6 and R7 divide the voltage at the first node b to obtain a second sampling voltage, and operational amplifier op1 differentially amplifies the first sampling voltage and the second sampling voltage to obtain a conditioned sampling voltage. The voltage monitor U1 controls the working state of the second switch tube G3 based on the conditioned sampling voltage.

[0169] The connection methods and working principles of other components are similar to Fig.11 The embodiments shown are the same and will not be described again.

[0170] To sum up, when the switching circuit of the energy recovery circuit enters the off state, the energy absorption circuit can absorb the peak voltage formed on the switching circuit by the current flowing through the primary coil, and perform high-voltage protection on the switching circuit. The energy recovery circuit also uses an energy transfer circuit to transfer the energy released by the energy absorption circuit to the front-end energy storage circuit, so that the recovered energy continues to be transmitted to the secondary coil, thereby improving the conversion efficiency of the power supply.

[0171] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

[0172] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them. Under the idea of ​​the present application, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. It should be understood by ordinary technicians in this field that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An energy recovery circuit, characterized in that: include: A front-end energy storage circuit is configured to store energy, the front-end energy storage circuit comprising a first node; A switch circuit including a second node; A controller, electrically connected to the switch circuit, configured to control the switch circuit to enter an on state or an off state; A transformer, comprising a coupled primary coil and a secondary coil, wherein the primary coil is electrically connected between the first node and the second node, and the primary coil is configured to transfer energy to the secondary coil based on the current output by the front-end energy storage circuit in response to the switch circuit entering an on state or an off state; an energy absorption circuit, electrically connected to the second node, configured to absorb and store the current flowing through the primary coil in response to the switch circuit entering an off state, the energy absorption circuit comprising a third node; an energy transfer circuit, electrically connected to the third node and also electrically connected to the front-end energy storage circuit; The energy control circuit is electrically connected to the energy transfer circuit and is configured to control the energy transfer circuit to transfer the energy absorbed by the energy absorption circuit to the front-end energy storage circuit for storage.

2. The energy recovery circuit according to claim 1, characterized in that: The energy control circuit is configured to control the energy transfer circuit to adjust the energy absorption circuit to be in a voltage stabilization state, so that the voltage across the primary coil is in a voltage stabilization state after the switch circuit is turned off, and the current flowing through the primary coil decreases evenly.

3. The energy recovery circuit according to claim 2, characterized in that: The energy control circuit comprises: a voltage stabilization control circuit, electrically connected to the energy absorption circuit and the energy transfer circuit, respectively, and configured to control the energy transfer circuit to adjust the energy absorption circuit to be in a voltage stabilization state, so that the voltage across the primary coil is in a voltage stabilization state after the switch circuit is turned off, and the current flowing through the primary coil is uniformly reduced; A delay circuit is electrically connected to the voltage stabilization control circuit and is configured to control the response of the voltage stabilization control circuit to lag behind the change of the voltage across the energy absorption circuit.

4. The energy recovery circuit according to claim 3, characterized in that: The voltage stabilization control circuit comprises: a voltage detection circuit, electrically connected to the energy absorption circuit and the delay circuit, respectively, and configured to detect the voltage across the energy absorption circuit to obtain a sampled voltage, wherein the delay circuit is configured to control the sampled voltage to lag behind the change of the voltage across the energy absorption circuit; The voltage monitoring circuit is electrically connected to the voltage detection circuit and the energy transfer circuit respectively, and is configured to control the working state of the energy transfer circuit based on the sampled voltage.

5. The energy recovery circuit according to claim 4, characterized in that: The voltage detection circuit is electrically connected between the first node and the third node, and is configured to detect the voltage across the energy absorption circuit, obtain a sampled voltage, and transmit the sampled voltage to the voltage monitoring circuit.

6. The energy recovery circuit according to claim 5, characterized in that: The voltage detection circuit includes a first resistor and a second resistor, one end of the first resistor is electrically connected to the third node, the other end of the first resistor and one end of the second resistor are electrically connected to a fourth node, the voltage monitoring circuit is electrically connected to the fourth node, and the other end of the second resistor is electrically connected to the first node.

7. The energy recovery circuit according to claim 4, characterized in that: The voltage detection circuit comprises: a first voltage sampling branch, a second voltage sampling branch and an operational amplifier; a first voltage sampling branch, electrically connected between the first node and the ground, the first voltage sampling branch comprising a fifth node, the inverting input terminal of the operational amplifier being electrically connected to the fifth node, and the first voltage sampling branch being configured to detect a voltage at the first node to obtain a first sampled voltage; a second voltage sampling branch, electrically connected between the third node and the ground, the second voltage sampling branch comprising a sixth node, the non-inverting input terminal of the operational amplifier electrically connected to the sixth node, the output terminal of the operational amplifier electrically connected to the voltage monitoring circuit, and the second voltage sampling branch being configured to detect the voltage at the third node to obtain a second sampled voltage; The operational amplifier is configured to perform signal conditioning processing on the first sampling voltage and the second sampling voltage to obtain conditioned sampling voltages.

8. The energy recovery circuit according to claim 7, characterized in that: The transformer further comprises an auxiliary coil, wherein the auxiliary coil is coupled to the primary coil; The voltage detection circuit also includes a power input circuit, which is electrically connected to the auxiliary coil and the operational amplifier, respectively, and is configured to provide working power to the operational amplifier.

9. The energy recovery circuit according to any one of claims 4 to 8, characterized in that: The voltage monitoring circuit is configured to control the energy transfer circuit to transfer the energy absorbed by the energy absorption circuit in response to the sampling voltage being greater than a preset reference voltage; or, The voltage monitoring circuit is configured to control the energy transfer circuit to stop transferring the energy absorbed by the energy absorption circuit in response to the sampling voltage being less than or equal to a preset reference voltage.

10. The energy recovery circuit according to claim 4, characterized in that: The delay circuit includes a delay capacitor, and the delay capacitor is electrically connected to an input node between the voltage detection circuit and the voltage monitoring circuit.

11. The energy recovery circuit according to any one of claims 1 to 8, characterized in that: The energy transfer circuit comprises: An energy processing circuit, electrically connected to the energy absorption circuit and the front-end energy storage circuit respectively; The transfer control circuit is electrically connected to the energy control circuit and the energy processing circuit, respectively, and is configured to respond to a first start signal transmitted by the energy control circuit to control the energy processing circuit to receive energy released by the energy absorption circuit, or respond to a first stop signal transmitted by the energy control circuit to control the energy processing circuit to stop receiving energy released by the energy absorption circuit. In the stopped state, the energy processing circuit transmits the received energy back to the front-end energy storage circuit for storage.

12. The energy recovery circuit according to claim 11, characterized in that: The energy processing circuit comprises: An energy storage transfer unit, electrically connected to the front-end energy storage circuit; The first switch unit is electrically connected to the energy absorption circuit and the transfer control circuit, respectively, and is configured to respond to a second start signal transmitted by the transfer control circuit to enter an on state, so that the energy released by the energy absorption circuit flows to the energy storage transfer unit through the first switch unit for storage, or, respond to a second stop signal transmitted by the transfer control circuit to enter an off state to block the energy released by the energy absorption circuit from flowing to the energy storage transfer unit through the first switch unit for storage, and to enable the energy storage transfer unit to transfer the stored energy to the front-end energy storage circuit.

13. The energy recovery circuit according to claim 12, characterized in that: The first switch unit includes a first switch tube, which is electrically connected to the energy absorption circuit, the transfer control circuit and the energy storage transfer unit respectively, and is configured to enter an on state in response to the second start signal, or to enter an off state in response to the second stop signal.

14. The energy recovery circuit according to claim 12, characterized in that: The energy storage transfer unit comprises: an energy storage inductor, one end of which is electrically connected to the first switch unit, and the other end of which is electrically connected to the front-end energy storage circuit; A first unidirectional conduction circuit, one end of the first unidirectional conduction circuit is electrically connected to one end of the energy storage inductor, the other end of the first unidirectional conduction circuit is grounded together with the ground end of the front-end energy storage circuit, and the first unidirectional conduction circuit is configured so that when the first switch unit enters the off state, the current flowing through the energy storage inductor can flow back to the front-end energy storage circuit through the first unidirectional conduction circuit.

15. The energy recovery circuit according to claim 11, characterized in that: The transfer control circuit comprises: A second switch unit, electrically connected to the energy control circuit, and configured to enter an on state in response to the first start signal, or enter an off state in response to the first stop signal; The voltage divider unit is electrically connected to the third node, the energy processing circuit and the second switch unit, respectively, and is configured to respond to the second switch unit entering the on state by converting the voltage at the third node into a second start signal, so that the energy processing circuit responds to the second start signal and receives the energy released by the energy absorption circuit, or, respond to the second switch unit entering the off state, convert the voltage across the energy absorption circuit into a second stop signal, so that the energy processing circuit responds to the second stop signal and stops receiving the energy released by the energy absorption circuit.

16. The energy recovery circuit according to claim 15, characterized in that: The second switch unit includes a second switch tube, which is electrically connected to the energy control circuit and the voltage divider unit respectively, and is configured to enter an on state in response to the first start signal, or enter an off state in response to the first stop signal.

17. The energy recovery circuit according to any one of claims 1 to 8, characterized in that: The energy absorption circuit comprises: Absorption unit; A second unidirectional conducting circuit is electrically connected between the second node and the third node, and the second unidirectional conducting circuit is configured so that when the switching circuit enters the off state, the current flowing through the primary coil can flow back to the absorption unit through the second unidirectional conducting circuit for storage.

18. The energy recovery circuit according to claim 17, characterized in that: The absorption unit is electrically connected between the first node and the third node; or, The absorption unit is electrically connected between the third node and a ground terminal.

19. The energy recovery circuit according to claim 17, characterized in that: The absorption unit is a first capacitor.

20. The energy recovery circuit according to any one of claims 1 to 8, characterized in that: The front-end energy storage circuit is a second capacitor, one end of the second capacitor is electrically connected to the first node, and the other end of the second capacitor is grounded.

21. The energy recovery circuit according to any one of claims 1 to 8, characterized in that: The switching circuit includes a main switching tube, which is electrically connected to the primary coil and also electrically connected to the controller, and is configured to respond to a conduction signal sent by the controller to enter an on state, or respond to a shutdown signal sent by the controller to enter an off state.

22. The energy recovery circuit according to any one of claims 1 to 8, characterized in that: The transformer operates in a flyback mode or a forward mode.

23. An electrical device, characterized in that: Comprising an energy recovery circuit as claimed in any one of claims 1 to 22.

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