High-energy-efficiency outdoor switching power supply

Abstract

The utility model relates to the technical field of switching power supplies, in particular to a high-energy-efficiency outdoor switching power supply, which comprises a rectifier bridge BD1, a PFC (Power Factor Correction) module, an LLC (Logical Link Control) power module and a transformer T1, the output end of the rectifier bridge BD1 is electrically connected with the PFC module, the PFC module is electrically connected with the LLC power module, and the LLC power module is electrically connected with a primary winding of the transformer T1; the number of contact surfaces between magnetic cores of the transformer T1 is less than four; the problem that a traditional switching power supply is not suitable for an outdoor environment due to insufficient stability and energy efficiency is solved.

Description

Technical Field

[0001] This utility model relates to the field of switching power supply technology, and in particular to a high-efficiency outdoor switching power supply. Background Technology

[0002] With the rapid development of outdoor lighting, outdoor communication equipment, and outdoor security monitoring, the demand for outdoor switching power supplies is increasing. However, the outdoor environment is complex and changeable, and harsh conditions such as high temperature, low temperature, humidity, and dust pose serious challenges to the reliability, energy efficiency, and lifespan of power supplies.

[0003] Currently, mainstream switching power supplies of 50W and above typically use single-stage high-PF switching power supplies (i.e., adding a PFC module to improve the power factor). However, due to the presence of 50Hz / 60Hz voltage frequency ripple, such switching power supplies require a large-capacity output electrolytic capacitor to reduce the ripple current. At the same time, in order to further reduce the ripple current and achieve the purpose of eliminating flicker, switching power supplies generally reduce the output ripple current in a depletion-type manner by adding an IC with flicker-eliminating function to drive the MOSFET. This results in the overall energy efficiency of the switching power supply not exceeding 87% at most, and the ripple current is still as high as 70%, and flicker still exists.

[0004] Clearly, the performance of mainstream switching power supplies on the market still cannot meet the needs of outdoor switching power supplies. Ripple current and flicker will have amplified effects on the overall circuit of the switching power supply in outdoor environments, seriously affecting the stability of the switching power supply and further reducing its energy efficiency in outdoor environments. Utility Model Content

[0005] To address the aforementioned shortcomings, the purpose of this invention is to propose a high-efficiency outdoor switching power supply, which solves the problem that traditional switching power supplies are unsuitable for outdoor environments due to insufficient stability and energy efficiency.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A high-efficiency outdoor switching power supply includes a rectifier bridge BD1, a PFC module, an LLC power module, and a transformer T1; the output terminal of the rectifier bridge BD1 is electrically connected to the PFC module, the PFC module is electrically connected to the LLC power module, and the LLC power module is electrically connected to the primary winding of the transformer T1.

[0008] The transformer T1 has fewer than four contact surfaces between its magnetic cores.

[0009] Furthermore, the magnetic core of the transformer T1 is of type EE.

[0010] Furthermore, it also includes a safety module, which includes a fuse F1, a varistor VR1, a thermistor RNT1, a safety capacitor CX1, a resistor R1, a resistor R2, a common-mode inductor LF1, a differential-mode inductor L1, a resistor R3, and a varistor VR2.

[0011] The live wire is connected in series with the fuse F1 and the thermistor RNT1, and then electrically connected to one end of the first winding of the common-mode inductor LF1; the neutral wire is electrically connected to one end of the second winding of the common-mode inductor LF1; the varistor VR1 is connected in parallel between the common junction of the fuse F1 and the thermistor RNT1 and the neutral wire; the safety capacitor CX1 is connected in parallel between the common junction of the thermistor RNT1 and the common-mode inductor LF1 and the neutral wire; the resistors R1 and R2 are connected in series... A resistor R3 is connected in parallel between the common junction of the thermistor RNT1 and the common-mode inductor LF1 and the neutral wire; the other end of the first winding of the common-mode inductor LF1 is electrically connected to one end of the varistor VR2; the other end of the second winding of the common-mode inductor LF1 is connected in series with the differential-mode inductor L1 and then electrically connected to the other end of the varistor VR2; the resistor R3 is connected in parallel across the two ends of the differential-mode inductor L1, and one end and the other end of the varistor VR2 are both electrically connected to the input terminal of the rectifier bridge BD1.

[0012] Furthermore, the safety block also includes capacitors CY3 and CY4; the common connection point of resistor R3, differential mode inductor L1, and common mode inductor LF1 is electrically connected to one end of capacitor CY3, and the common connection point of varistor VR2 and common mode inductor LF1 is electrically connected to one end of capacitor CY4; the other ends of capacitor CY3 and capacitor CY4 are electrically connected and then grounded.

[0013] Furthermore, it also includes a power reduction module, which includes a low-voltage detection circuit, a diode D7, resistors R17, R20, R21, R27, R28, R28A, an adjustable resistor RXT, resistors RS4, RS5, RS6, RS9, a MOSFET Q2, and at least one resistor R4.

[0014] The positive output terminal of the rectifier bridge BD1 is connected in series with at least one resistor R4 and then electrically connected to the input terminal of the low-voltage detection circuit. The output terminal of the low-voltage detection circuit is electrically connected to the anode of the diode D7, and the cathode of the diode D7 is electrically connected to the gate of the MOSFET Q2. Resistor R17 is connected in parallel between the gate of the MOSFET Q2 and ground. The source of the MOSFET Q2 is connected in series with resistor RS6 and then grounded. Resistor RS5 is connected in parallel across resistor RS6. Resistor RS4 is connected in parallel between the drain of the MOSFET Q2 and ground. The resistors R9, R21, and R20 are all electrically connected to the drain of the MOSFET Q2. The other ends of R21, R20, R28, and R28A are all electrically connected to one end of the resistor R27. The other ends of R28 and R28A are all electrically connected to one end of the adjustable resistor RXT. One end of the adjustable resistor RXT is grounded. The other end of the resistor R27 is electrically connected to the current sampling terminal of the LLC power module.

[0015] Furthermore, the low-voltage detection circuit consists of a low-voltage detection chip U3 and its peripheral circuitry.

[0016] The technical solution provided by this utility model can include the following beneficial effects: In the switching power supply circuit framework, the subsequent circuit of the rectifier bridge BD1 is composed of a PFC module and an LLC power module, which significantly reduces switching losses, improves the efficiency and power density of the power converter (transformer T1), outputs lower ripple current, removes power frequency ripple as much as possible, and achieves ripple current ≤3% and no flicker; at the same time, by reducing the number of contact surfaces between the magnetic cores of transformer T1, the magnetic resistance is reduced, thereby reducing the iron loss of transformer T1, so that the energy efficiency of the switching power supply can reach 90% or more; ultimately, the switching power supply meets the requirements of outdoor environments. Attached Figure Description

[0017] Figure 1 This is a circuit diagram of a high-efficiency outdoor switching power supply according to one embodiment of the present invention.

[0018] Figure 2 This is a comparison diagram of EE type magnetic cores and EIE type magnetic cores.

[0019] The components include: rectifier bridge BD1, PFC module 2, LLC power module 3, transformer T1, fuse F1, varistor VR1, thermistor RNT1, safety capacitor CX1, resistor R1, resistor R2, common mode inductor LF1, differential mode inductor L1, resistor R3, varistor VR2, capacitor CY3, capacitor CY4, low voltage detection circuit 41, diode D7, resistor R17, resistor R20, resistor R21, resistor R27, resistor R28, resistor R28A, adjustable resistor RXT, resistor RS4, resistor RS5, resistor RS6, resistor RS9, MOSFET Q2, and resistor R4. Detailed Implementation

[0020] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0021] In the description of embodiments of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of embodiments of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0022] In the description of the embodiments of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this utility model according to the specific circumstances.

[0023] The following is combined with Figures 1 to 2 This invention describes a high-efficiency outdoor switching power supply according to an embodiment of the present invention.

[0024] A high-efficiency outdoor switching power supply includes a rectifier bridge BD1, a PFC module 2, an LLC power module 3, and a transformer T1; the output terminal of the rectifier bridge BD1 is electrically connected to the PFC module 2, the PFC module 2 is electrically connected to the LLC power module 3, and the LLC power module 3 is electrically connected to the primary winding of the transformer T1.

[0025] There are fewer than four contact surfaces between the magnetic cores of transformer T1.

[0026] This utility model proposes a preferred embodiment of a high-efficiency outdoor switching power supply, such as... Figure 1 As shown, in the switching power supply circuit framework, after rectification by rectifier bridge BD1, the voltage is boosted and stabilized by PFC module 2 (composed of PFC chip U1 with peripheral circuitry built according to chip manual, such as BP2636D chip). Then, LLC power module 3 (composed of LLC power chip U2 with peripheral circuitry built according to chip manual, such as RSC6205A chip) eliminates voltage and current overlap during the switching process through a resonant network, realizing zero-voltage turn-on (ZVS) of the primary main switch and zero-current turn-off (ZCS) of the secondary rectifier diode, thereby eliminating power frequency ripple as much as possible, significantly reducing switching losses, improving the efficiency and power density of the power converter (transformer T1), outputting low ripple current, making the ripple current ≤3% and flicker-free. Meanwhile, the losses generated by transformer T1 during power conversion are mainly due to iron losses and copper losses. This design of transformer T1 focuses on reducing iron losses. Considering that dust or other media may be present on the contact surfaces between magnetic cores during the manufacturing process, it is impossible to achieve 100% fit and zero magnetic reluctance. In addition, some magnetic core contact surfaces require grinding to adjust leakage inductance, further causing unevenness in the contact surfaces. Therefore, the more contact surfaces there are, the greater the magnetic reluctance. Thus, by reducing the number of contact surfaces between magnetic cores, the magnetic reluctance can be reduced, thereby reducing the iron losses of transformer T1 and enabling the switching power supply to achieve an efficiency of 90% or higher. Ultimately, this allows the switching power supply to meet the requirements of outdoor environments.

[0027] Furthermore, the magnetic core of transformer T1 is of type EE.

[0028] In this embodiment, to reduce the number of contact surfaces between the magnetic cores of transformer T1, the magnetic core of transformer T1 is preferably of type EE. For example... Figure 2 As shown, the commonly used EIE type magnetic core consists of two E-shaped magnetic cores and one I-shaped magnetic core, with six contact surfaces. The leakage inductance of the EIE type magnetic core is mainly adjusted by adjusting the distance between the central column of the two E-shaped magnetic cores and the I-shaped magnetic core. This requires grinding the central column of the two E-shaped magnetic cores, resulting in a larger total magnetic reluctance (or iron loss) for the EIE type magnetic core. In contrast, the EE type magnetic core has only three contact surfaces, and the leakage inductance is mainly adjusted by the spacing between the primary and secondary intermediate baffles, resulting in a smaller total magnetic reluctance (or iron loss). More importantly, the EE type magnetic core has one less I-shaped magnetic core, which can ultimately reduce the cost by 35%.

[0029] Furthermore, it also includes safety module 1, which includes fuse F1, varistor VR1, thermistor RNT1, safety capacitor CX1, resistor R1, resistor R2, common mode inductor LF1, differential mode inductor L1, resistor R3 and varistor VR2.

[0030] The live wire is connected in series with fuse F1 and thermistor RNT1, and then electrically connected to one end of the first winding of common-mode inductor LF1; the neutral wire is electrically connected to one end of the second winding of common-mode inductor LF1; varistor VR1 is connected in parallel between the common junction of fuse F1 and thermistor RNT1 and the neutral wire; safety capacitor CX1 is connected in parallel between the common junction of thermistor RNT1 and common-mode inductor LF1 and the neutral wire; resistors R1 and R2 are connected in series and then in parallel between the common junction of thermistor RNT1 and common-mode inductor LF1 and the neutral wire; the other end of the first winding of common-mode inductor LF1 is electrically connected to one end of varistor VR2; the other end of the second winding of common-mode inductor LF1 is connected in series with differential-mode inductor L1 and then electrically connected to the other end of varistor VR2; resistor R3 is connected in parallel across the two ends of differential-mode inductor L1; one end and the other end of varistor VR2 are both electrically connected to the input terminal of rectifier bridge BD1.

[0031] In this embodiment, the circuit structure of safety block 1 is preferably composed of safety capacitors, varistors, thermistors, differential mode inductors, and common mode inductors as the core components. Compared with conventional safety circuits that are only composed of safety capacitors, varistors, and common mode inductors, the energy efficiency can be further improved, enabling the switching power supply to achieve an energy efficiency of 94% or higher. At the same time, it also has low input voltage drop power, over-temperature power drop and short circuit protection functions, which improves the stability of outdoor switching power supplies.

[0032] It should be noted that excessively high or low impedance of varistors, thermistors, differential-mode inductors, and common-mode inductors will lead to energy efficiency loss. Therefore, it is necessary to select appropriate components based on experimental testing in order to ensure that the energy efficiency reaches 94%.

[0033] Furthermore, the safety block 1 also includes capacitors CY3 and CY4; the common connection point of resistor R3, differential mode inductor L1 and common mode inductor LF1 is electrically connected to one end of capacitor CY3, and the common connection point of varistor VR2 and common mode inductor LF1 is electrically connected to one end of capacitor CY4; after the other ends of capacitor CY3 and capacitor CY4 are electrically connected, a ground wire is connected.

[0034] In this embodiment, based on the fact that the safety block 1 has a varistor, a thermistor, a differential mode inductor and a common mode inductor, after being connected to the ground wire through capacitors CY3 and CY4, it can also be used as a lightning protection circuit to achieve input lightning protection of 4KV common mode and 6KV differential mode, making the switching power supply more compatible with lightning protection and stability and more suitable for outdoor environments.

[0035] Furthermore, it also includes a power reduction module 4, which includes a low-voltage detection circuit 41, a diode D7, resistors R17, R20, R21, R27, R28, R28A, an adjustable resistor RXT, resistors RS4, RS5, RS6, RS9, a MOSFET Q2, and at least one resistor R4.

[0036] The positive terminal of the rectifier bridge BD1 is connected in series with at least one resistor R4 and then electrically connected to the input terminal of the low-voltage detection circuit 41. The output terminal of the low-voltage detection circuit 41 is electrically connected to the anode of diode D7, and the cathode of diode D7 is electrically connected to the gate of MOSFET Q2. Resistor R17 is connected in parallel between the gate of MOSFET Q2 and ground. The source of MOSFET Q2 is connected in series with resistor RS6 and then grounded. Resistor RS5 is connected in parallel across resistor RS6. A resistor R is connected in parallel between the drain of MOSFET Q2 and ground. S4 and resistor RS9, one end of resistor R21 and one end of resistor R20 are electrically connected to the drain of MOSFET Q2, the other end of resistor R21, the other end of resistor R20, one end of resistor R28 and one end of resistor R28A are electrically connected to one end of resistor R27, the other end of resistor R28 and the other end of resistor R28A are electrically connected to one end of adjustable resistor RXT, one end of adjustable resistor RXT is grounded, and the other end of resistor R27 is electrically connected to the current sampling terminal of LLC power module 3.

[0037] In this embodiment, since the constant current switching power supply is designed to prevent the lamp from going out when the voltage drops, after sampling from the rectifier bridge B1, the signal is limited by at least one resistor R4 and high-frequency interference is suppressed before being sent to the low-voltage detection circuit 41 for fault logic judgment. Then, by driving the MOSFET Q2 to turn on or off, the equivalent resistance value connected to the current sampling terminal (CS terminal) of the LLC power module 3 is changed, thereby reducing the power of the LLC power module 3. This ensures the stability and energy efficiency of the switching power supply when the voltage drops (i.e., by reducing power, eliminating flicker, and reducing energy consumption). It should be noted that after the MOSFET Q2 is turned off, resistors RS5 and RS6 are disconnected, thereby reducing the power. If the resistance values ​​of resistors RS5 and RS6 are halved compared to those of resistors RS4 and RS9, the power will be halved. In addition, resistors R27, R28, R28A and adjustable resistor RXT constitute the output current regulation circuit. By adjusting the adjustable resistor RXT, the voltage across the equivalent resistance composed of resistors RS4, RS5, RS6, RS9 and MOSFET Q2 is changed, thereby changing the output current and keeping the reference voltage of the output current detection pin at the CS terminal of the U2 chip constant; thus achieving different current outputs according to different load voltages.

[0038] Furthermore, the low-voltage detection circuit 41 is composed of the low-voltage detection chip U3 and its peripheral circuits.

[0039] In this embodiment, considering the waterproofing of outdoor switching power supplies, the low-voltage detection circuit 41 preferably uses a packaged low-voltage detection chip U3 and its peripheral circuits. Compared with a circuit with fault judgment logic built from independent components, the circuit has better waterproofing performance.

[0040] For example, when the low-voltage detection chip U3 is an OB3631 chip (with an integrated comparator), its input terminals are OVR (overvoltage terminal) and BRO (undervoltage terminal). The internal overvoltage reference voltage can be set to 2V, and the undervoltage reference voltage can be set to 0.5V. When the detected voltage is higher than 2V (returning to normal) or lower than 0.5V (low voltage), the internal transistor drive terminal (DRP terminal) controls the conduction or cutoff of the MOSFET Q2, thereby realizing low-voltage detection.

[0041] Other components and operations of a high-efficiency outdoor switching power supply according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0042] In this specification, the terms "embodiment," "example," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A high-efficiency outdoor switching power supply, characterized in that: It includes a rectifier bridge BD1, a PFC module, an LLC power module, and a transformer T1; the output terminal of the rectifier bridge BD1 is electrically connected to the PFC module, the PFC module is electrically connected to the LLC power module, and the LLC power module is electrically connected to the primary winding of the transformer T1. The transformer T1 has fewer than four contact surfaces between its magnetic cores.

2. The high-efficiency outdoor switching power supply according to claim 1, characterized in that: The magnetic core of the transformer T1 is of type EE.

3. The high-efficiency outdoor switching power supply according to claim 1, characterized in that: It also includes a safety module, which includes a fuse F1, a varistor VR1, a thermistor RNT1, a safety capacitor CX1, a resistor R1, a resistor R2, a common-mode inductor LF1, a differential-mode inductor L1, a resistor R3, and a varistor VR2. The live wire is connected in series with the fuse F1 and the thermistor RNT1, and then electrically connected to one end of the first winding of the common-mode inductor LF1; the neutral wire is electrically connected to one end of the second winding of the common-mode inductor LF1; the varistor VR1 is connected in parallel between the common junction of the fuse F1 and the thermistor RNT1 and the neutral wire; the safety capacitor CX1 is connected in parallel between the common junction of the thermistor RNT1 and the common-mode inductor LF1 and the neutral wire; the resistors R1 and R2 are connected in series... A resistor R3 is connected in parallel between the common junction of the thermistor RNT1 and the common-mode inductor LF1 and the neutral wire; the other end of the first winding of the common-mode inductor LF1 is electrically connected to one end of the varistor VR2; the other end of the second winding of the common-mode inductor LF1 is connected in series with the differential-mode inductor L1 and then electrically connected to the other end of the varistor VR2; the resistor R3 is connected in parallel across the two ends of the differential-mode inductor L1, and one end and the other end of the varistor VR2 are both electrically connected to the input terminal of the rectifier bridge BD1.

4. The high-efficiency outdoor switching power supply according to claim 3, characterized in that: The safety block also includes capacitors CY3 and CY4; the common connection point of resistor R3, differential mode inductor L1, and common mode inductor LF1 is electrically connected to one end of capacitor CY3, and the common connection point of varistor VR2 and common mode inductor LF1 is electrically connected to one end of capacitor CY4; the other ends of capacitor CY3 and capacitor CY4 are electrically connected and then grounded.

5. A high-efficiency outdoor switching power supply according to claim 1, characterized in that: It also includes a power reduction module, which includes a low-voltage detection circuit, a diode D7, resistors R17, R20, R21, R27, R28, R28A, an adjustable resistor RXT, resistors RS4, RS5, RS6, RS9, a MOSFET Q2, and at least one resistor R4. The positive output terminal of the rectifier bridge BD1 is connected in series with at least one resistor R4 and then electrically connected to the input terminal of the low-voltage detection circuit. The output terminal of the low-voltage detection circuit is electrically connected to the anode of the diode D7, and the cathode of the diode D7 is electrically connected to the gate of the MOSFET Q2. Resistor R17 is connected in parallel between the gate of the MOSFET Q2 and ground. The source of the MOSFET Q2 is connected in series with resistor RS6 and then grounded. Resistor RS5 is connected in parallel across resistor RS6. Resistor RS4 is connected in parallel between the drain of the MOSFET Q2 and ground. The resistors R9, R21, and R20 are all electrically connected to the drain of the MOSFET Q2. The other ends of R21, R20, R28, and R28A are all electrically connected to one end of the resistor R27. The other ends of R28 and R28A are all electrically connected to one end of the adjustable resistor RXT. One end of the adjustable resistor RXT is grounded. The other end of the resistor R27 is electrically connected to the current sampling terminal of the LLC power module.

6. A high-efficiency outdoor switching power supply according to claim 5, characterized in that: The low-voltage detection circuit consists of a low-voltage detection chip U3 and its peripheral circuits.

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