AC / DC switching power supply

Abstract

The invention relates to the technical field of switching power supplies, in particular to an AC / DC switching power supply, which comprises an input module used for processing an AC signal input to the AC / DC switching power supply; the conversion module is connected with the input module and is used for processing the direct current signal; the output module is connected with the conversion module and comprises an output filter and a voltage stabilizer, the output filter is connected with the transformer and used for filtering the output voltage, and the voltage stabilizer is connected with the output filter and used for stabilizing the output voltage; and the control module is respectively connected with the input module, the conversion module and the output module and is used for determining the operation stability of the AC / DC switching power supply according to the variance of the output current so as to determine whether to determine the duty ratio of the AC / DC switching power supply or determine the cut-off frequency of an output filter according to the average fluctuation amplitude of the output voltage. According to the invention, the operation stability of the AC / DC switching power supply is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of switching power supplies, and in particular to an AC / DC switching power supply. Background Art

[0002] In the prior art, an AC / DC switching power supply is a power supply device that converts alternating current (AC) into direct current (DC). This type of power supply is commonly used in various electronic devices and systems, such as computers, communication equipment, household appliances, etc., to provide the required DC power. AC / DC switching power supplies have many advantages over traditional linear power supplies, including higher efficiency, smaller size and weight, better deterministic performance, and a wider input voltage range. These features make switching power supplies widely used in modern electronic devices.

[0003] Chinese Patent Publication No.: CN101409511A discloses an AC / DC capacitor flyback switching power supply circuit, including an AC power supply, a diode I, a diode II, a diode III, a diode IV, a control switch I, a control switch II, a capacitor I, and a capacitor II. One end of the AC power supply is connected to the anode of the diode I and the cathode of the diode II respectively, and the other end is connected to the negative output end of the circuit; the control switch I is connected between the cathode of the diode I and the negative and positive output ends of the circuit, the control switch II is connected between the anode of the diode II and the negative output end of the circuit, the anode of the diode II is connected to the negative end of the capacitor II, the positive end of the capacitor II is connected to the cathode of the diode III and the anode of the diode IV respectively, the anode of the diode III is connected to the negative output end of the circuit, and the cathode of the diode IV is connected to the negative and positive output ends of the circuit; the positive end of the capacitor I is connected to the cathode of the diode I, and its negative end is connected to the negative output end of the circuit. It can be seen that the AC / DC capacitor flyback switching power supply circuit has the problem that the leakage current inside the switching power supply increases due to long-term use, resulting in an increase in power consumption in the circuit, thereby causing the operating stability of the AC / DC switching power supply to decrease. Summary of the invention

[0004] To this end, the present invention provides an AC / DC switching power supply to overcome the problem in the prior art that long-term use causes an increase in leakage current inside the switching power supply, resulting in an increase in power consumption in the circuit, thereby causing a decrease in the operating stability of the AC / DC switching power supply.

[0005] To achieve the above-mentioned object, the present invention provides an AC / DC switching power supply, comprising: an input module for processing an AC signal input to the AC / DC switching power supply, comprising an input filter for filtering the AC signal and a rectifier bridge connected to the input filter for converting the AC signal into a DC signal; a conversion module connected to the input module, for processing the DC signal, comprising a switch tube connected to the rectifier bridge for converting the DC signal into a high-frequency pulse and a transformer connected to the switch tube for converting the input voltage into a desired output voltage; an output module connected to the conversion module, comprising The invention comprises an output filter connected to the transformer for filtering the output voltage and a voltage stabilizer connected to the output filter for stabilizing the output voltage; a control module, which is respectively connected to the input module, the conversion module and the output module, and is used to determine the operation stability of the AC / DC switching power supply according to the variance of the output current, so as to determine whether to determine the duty cycle of the AC / DC switching power supply or determine the cut-off frequency of the output filter according to the average fluctuation amplitude of the output voltage, and determine the delayed start-up time of the AC / DC switching power supply according to the average fluctuation amplitude of the output voltage and the temperature rise rate of the surface of the AC / DC switching power supply.

[0006] Furthermore, the control module obtains the output current in several power supply cycles and calculates the variance of the output current. If the variance of the output current is greater than a preset first variance, it is determined that the operating stability of the AC / DC switching power supply does not meet the requirements.

[0007] Furthermore, when the variance of the output current is greater than the preset first variance and less than or equal to a preset second variance, the control module preliminarily determines that the environmental stability of the AC / DC switching power supply does not meet the requirements, and further determines whether the environmental stability of the AC / DC switching power supply meets the requirements based on the average fluctuation amplitude of the output voltage.

[0008] Further, the control module increases the duty cycle of the AC / DC switching power supply when the variance of the output current is greater than the preset second variance;

[0009] The increase range of the duty cycle of the AC / DC switching power supply is determined by the difference between the variance of the output current and a preset second variance.

[0010] Furthermore, the control module obtains the output voltage within several power supply cycles and calculates the average fluctuation amplitude of the output voltage. If the average fluctuation amplitude of the output voltage is greater than a preset first fluctuation amplitude, it is further determined that the environmental stability of the AC / DC switching power supply does not meet the requirements.

[0011] Furthermore, when the average fluctuation amplitude of the output voltage is greater than a preset second fluctuation amplitude, the control module preliminarily determines that the temperature of the AC / DC switching power supply is in an unstable state, and further determines whether the stable state of the temperature of the AC / DC switching power supply meets the requirements based on the temperature increase rate on the surface of the AC / DC switching power supply.

[0012] Furthermore, the control module increases the cutoff frequency of the output filter when the average fluctuation amplitude of the output voltage is greater than the preset first fluctuation amplitude and less than or equal to the preset second fluctuation amplitude;

[0013] The increase range of the cut-off frequency of the output filter is determined by the difference between the average fluctuation range of the output voltage and the preset first fluctuation range.

[0014] Furthermore, the average fluctuation amplitude of the output voltage is an average value of the difference between the maximum output voltage and the minimum output voltage in a plurality of power supply cycles.

[0015] Furthermore, the control module obtains the temperature of the surface of the AC / DC switching power supply within a single operating cycle, and calculates the temperature increase rate of the surface of the AC / DC switching power supply. If the temperature increase rate of the surface of the AC / DC switching power supply is greater than a preset increase rate, it is further determined that the temperature of the AC / DC switching power supply is in an unstable state, and the delayed startup time of the AC / DC switching power supply is reduced.

[0016] Further, the reduction range of the delayed startup time of the AC / DC switching power supply is determined by the difference between the temperature increase rate of the surface of the AC / DC switching power supply and a preset increase rate.

[0017] Compared with the prior art, the beneficial effect of the present invention lies in that the switching power supply of the present invention determines the duty cycle of the AC / DC switching power supply according to the variance of the output current by setting an input module, a conversion module, an output module and a control module. Due to long-term use, the leakage current inside the switching power supply increases, resulting in increased power consumption in the circuit, thereby causing a decrease in efficiency. By increasing the duty cycle of the AC / DC switching power supply, it is helpful to improve the stability and response speed of the output voltage, thereby reducing power consumption and improving efficiency. The cut-off frequency of the output filter is determined according to the average fluctuation amplitude of the output voltage. Since a fault in a switch tube in the switching power supply may cause a change in the switching frequency, resulting in a decrease in the power consumption. The source fluctuates, which in turn increases the possibility of electromagnetic interference. By increasing the cutoff frequency of the output filter, the filter can respond more quickly to high-frequency fluctuations in the power supply and reduce the impact of the switching frequency on the output. The delayed startup time of the AC / DC switching power supply is determined according to the temperature rise rate on the surface of the AC / DC switching power supply. Due to the long-term high-load operation of the switching power supply, the internal components generate more heat in the overload state, which increases the temperature of the switching power supply. By reducing the delayed startup time of the AC / DC switching power supply, the high impact current generated instantly at startup is reduced, which helps to reduce component load and heat loss and improve the operating stability of the AC / DC switching power supply.

[0018] Furthermore, the switching power supply described in the present invention determines the duty cycle of the AC / DC switching power supply by setting a preset first variance and a preset second variance. Due to long-term use, the leakage current inside the switching power supply increases, resulting in increased power consumption in the circuit, thereby causing a decrease in efficiency. By increasing the duty cycle of the AC / DC switching power supply, it is helpful to improve the stability and response speed of the output voltage, thereby reducing power consumption and improving efficiency, and further improving the operating stability of the AC / DC switching power supply.

[0019] Furthermore, the switching power supply described in the present invention determines the cutoff frequency of the output filter by setting a preset first fluctuation amplitude and a preset second fluctuation amplitude. Since a fault in a switching tube in the switching power supply may cause the switching frequency to change, causing power supply fluctuations, thereby increasing the possibility of electromagnetic interference, by increasing the cutoff frequency of the output filter, the filter can respond more quickly to high-frequency fluctuations in the power supply, reducing the impact of the switching frequency on the output, and further improving the operating stability of the AC / DC switching power supply.

[0020] Furthermore, the switching power supply described in the present invention determines the delayed startup time of the AC / DC switching power supply by setting a preset increase rate. Since the switching power supply operates at a high load for a long time, the internal components generate more heat in an overload state, causing the temperature of the switching power supply to rise. By reducing the delayed startup time of the AC / DC switching power supply, the high impact current generated instantly during startup is reduced, which helps to reduce component load and heat loss, and further improves the operating stability of the AC / DC switching power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The overall structure block diagram of the AC / DC switching power supply according to the embodiment of the present invention;

[0022] Figure 2 The following is a logic flow chart of the AC / DC switching power supply according to an embodiment of the present invention;

[0023] Figure 3 This is a specific structural block diagram of an input module of an AC / DC switching power supply according to an embodiment of the present invention;

[0024] Figure 4 The figure is a specific structural block diagram of a conversion module of an AC / DC switching power supply according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0027] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0028] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] See also Figure 1 , Figure 2 , Figure 3 as well as Figure 4 As shown, they are respectively an overall structural block diagram of an AC / DC switching power supply according to an embodiment of the present invention, a logic flow chart, a specific structural block diagram of an input module, and a specific structural block diagram of a conversion module. An AC / DC switching power supply according to the present invention comprises:

[0030] An input module, used for processing an AC signal input to the AC / DC switching power supply, including an input filter for filtering the AC signal and a rectifier bridge connected to the input filter for converting the AC signal into a DC signal;

[0031] A conversion module, which is connected to the input module and is used to process the DC signal, including a switch tube connected to the rectifier bridge to convert the DC signal into a high-frequency pulse and a transformer connected to the switch tube to convert the input voltage into a required output voltage;

[0032] an output module connected to the conversion module, comprising an output filter connected to the transformer for filtering the output voltage and a voltage stabilizer connected to the output filter for stabilizing the output voltage;

[0033] A control module, which is respectively connected to the input module, the conversion module and the output module, is used to determine the operating stability of the AC / DC switching power supply according to the variance of the output current, so as to determine whether to determine the duty cycle of the AC / DC switching power supply or determine the cut-off frequency of the output filter according to the average fluctuation amplitude of the output voltage, and to determine the delayed start-up time of the AC / DC switching power supply according to the average fluctuation amplitude of the output voltage and the temperature rise rate of the surface of the AC / DC switching power supply.

[0034] Specifically, the input filter can be an EMI filter, an LC filter, or a Pi filter.

[0035] Specifically, the switch tube can be MOSFET, IGBT, or BJT.

[0036] Specifically, the output filter may be an LC filter, a Pi filter, or an RC filter.

[0037] Specifically, the voltage regulator may be a linear voltage regulator, a switching voltage regulator, or a closed-loop control voltage regulator.

[0038] Specifically, the duty cycle of an AC / DC switching power supply is the ratio of the time that the switch tube is in the on state in a single cycle to the length of the entire cycle.

[0039] Specifically, the delayed startup time of the AC / DC switching power supply is the time interval from when the AC / DC switching power supply is turned on to when the output voltage starts to work stably.

[0040] In implementation, the switching power supply of the present invention determines the duty cycle of the AC / DC switching power supply according to the variance of the output current by setting an input module, a conversion module, an output module and a control module. Due to long-term use, the leakage current inside the switching power supply increases, resulting in increased power consumption in the circuit, thereby causing a decrease in efficiency. By increasing the duty cycle of the AC / DC switching power supply, it is helpful to improve the stability and response speed of the output voltage, thereby reducing power consumption and improving efficiency. The cutoff frequency of the output filter is determined according to the average fluctuation amplitude of the output voltage. Since a fault in the switch tube in the switching power supply may cause the switching frequency to change, causing the power supply to fluctuate, the switching frequency may change. This increases the possibility of electromagnetic interference. By increasing the cutoff frequency of the output filter, the filter can respond more quickly to high-frequency fluctuations in the power supply, reducing the impact of the switching frequency on the output. The delayed startup time of the AC / DC switching power supply is determined based on the temperature rise rate on the surface of the AC / DC switching power supply. Due to the long-term high-load operation of the switching power supply, the internal components generate more heat in an overload state, causing the temperature of the switching power supply to rise. By reducing the delayed startup time of the AC / DC switching power supply, the high impact current generated instantly at startup is reduced, which helps to reduce component load and heat loss and improve the operating stability of the AC / DC switching power supply.

[0041] Specifically, the control module obtains the output current in several power supply cycles and calculates the variance of the output current. If the variance of the output current is greater than a preset first variance, it is determined that the operating stability of the AC / DC switching power supply does not meet the requirements.

[0042] Specifically, when the variance of the output current is greater than the preset first variance and less than or equal to the preset second variance, the control module preliminarily determines that the environmental stability of the AC / DC switching power supply does not meet the requirements, and further determines whether the environmental stability of the AC / DC switching power supply meets the requirements based on the average fluctuation amplitude of the output voltage.

[0043] It can be understood that the three intervals corresponding to the preset first variance Q1 and the preset second variance Q2 correspond to three situations respectively. The first interval is Q≤Q1, corresponding to the situation where the operating stability of the AC / DC switching power supply meets the requirements; the second interval is Q1<Q≤Q2, corresponding to the situation where the switch tube failure in the switching power supply may cause the switching frequency to change, resulting in power supply fluctuations, and thus increasing the possibility of electromagnetic interference; the third interval is Q>Q2, corresponding to the situation where long-term use leads to an increase in the leakage current inside the switching power supply, resulting in an increase in power consumption in the circuit, thereby resulting in a decrease in efficiency. In practice, Q1 is generally selected in the range of [4A 2 , 6A 2 ], Q2 is generally selected in the range of [6A 2 , 8A 2 ].

[0044] Preferably, the preferred embodiment of the preset first variance Q1 is 5A 2 The preferred embodiment of the preset second variance Q2 is 7A 2 .

[0045] Specifically, the variance of the output current is denoted as Q.

[0046] Specifically, the variance of the output current is the variance of the output current within several power supply cycles. The calculation method of the variance of the output current is a conventional technical means well known to those skilled in the art, so the calculation process of the variance of the output current is not repeated here.

[0047] In implementation, the switching power supply of the present invention determines the operating stability of the AC / DC switching power supply by setting a preset first variance and a preset second variance, thereby reducing the impact of the reduced operating accuracy of the AC / DC switching power supply due to inaccurate determination of the operating stability of the AC / DC switching power supply, and further improving the operating stability of the AC / DC switching power supply.

[0048] Specifically, the control module increases the duty cycle of the AC / DC switching power supply when the variance of the output current is greater than the preset second variance;

[0049] The increase range of the duty cycle of the AC / DC switching power supply is determined by the difference between the variance of the output current and a preset second variance.

[0050] Specifically, the calculation formula for the increased duty cycle of the AC / DC switching power supply is:

[0051]

[0052] Wherein, V' is the increased duty cycle of the AC / DC switching power supply, V is the current duty cycle of the AC / DC switching power supply, A is the minimum unit variance for determining the duty cycle of the AC / DC switching power supply, and v is the duty cycle of the AC / DC switching power supply when the variance of the output current is the minimum unit variance.

[0053] In practice, the value of A is generally 7A. 2 ~9A 2 , preferably, the preferred embodiment of A is 8A 2 .

[0054] In implementation, the optional range of the value of v is [45%, 55%]. Preferably, when the duty cycle of the AC / DC switching power supply is less than 50%, it may cause increased power consumption in the circuit, so the preferred embodiment of v is 50%.

[0055] For example, an AC / DC switching power supply is used for power supply, where V = 45%, Q = 11A 2 , calculated

[0056]

[0057] In implementation, the switching power supply of the present invention determines the duty cycle of the AC / DC switching power supply by setting a preset first variance and a preset second variance. Due to long-term use, the leakage current inside the switching power supply increases, resulting in increased power consumption in the circuit, thereby causing a decrease in efficiency. By increasing the duty cycle of the AC / DC switching power supply, it is helpful to improve the stability and response speed of the output voltage, thereby reducing power consumption and improving efficiency, and further improving the operating stability of the AC / DC switching power supply.

[0058] Specifically, the control module obtains the output voltage within several power supply cycles and calculates the average fluctuation amplitude of the output voltage. If the average fluctuation amplitude of the output voltage is greater than a preset first fluctuation amplitude, it is further determined that the environmental stability of the AC / DC switching power supply does not meet the requirements.

[0059] Specifically, when the average fluctuation amplitude of the output voltage is greater than a preset second fluctuation amplitude, the control module preliminarily determines that the temperature of the AC / DC switching power supply is in an unstable state, and further determines whether the stable state of the temperature of the AC / DC switching power supply meets the requirements based on the temperature increase rate on the surface of the AC / DC switching power supply.

[0060] It can be understood that the three intervals corresponding to the preset first fluctuation amplitude P1 and the preset second fluctuation amplitude P2 correspond to three situations respectively. The first interval is P≤P1, corresponding to the situation where the environmental stability of the AC / DC switching power supply meets the requirements; the second interval is P1<P≤P2, corresponding to the situation where the switching tube failure in the switching power supply may cause the switching frequency to change, causing the power supply to fluctuate, and then increasing the possibility of electromagnetic interference; the third interval is P>P2, corresponding to the situation where the switching power supply runs at a high load for a long time, causing the internal components to generate more heat in an overload state, causing the temperature of the switching power supply to rise. In practice, the range of P1 is generally selected from [2V, 4V], and the range of P2 is generally selected from [4V, 6V].

[0061] Preferably, the first fluctuation amplitude P1 is preset to be 3V, and the second fluctuation amplitude P2 is preset to be 5V.

[0062] Specifically, the average fluctuation amplitude of the output voltage is denoted as P.

[0063] Specifically, the calculation formula for the average fluctuation amplitude of the output voltage is:

[0064] P=S1-S2

[0065] Wherein, P is the average fluctuation amplitude of the output voltage, S1 is the maximum output voltage within a number of power supply cycles, and S2 is the minimum output voltage within a number of power supply cycles.

[0066] In implementation, the switching power supply of the present invention further determines the environmental stability of the AC / DC switching power supply by setting a preset first fluctuation amplitude and a preset second fluctuation amplitude, thereby reducing the impact of the reduced operating stability of the AC / DC switching power supply due to inaccurate further determination of the environmental stability of the AC / DC switching power supply, and further improving the operating stability of the AC / DC switching power supply.

[0067] Specifically, the control module increases the cutoff frequency of the output filter when the average fluctuation amplitude of the output voltage is greater than the preset first fluctuation amplitude and less than or equal to the preset second fluctuation amplitude;

[0068] The increase range of the cut-off frequency of the output filter is determined by the difference between the average fluctuation range of the output voltage and a preset first fluctuation range.

[0069] Specifically, the calculation formula for the cutoff frequency of the increased output filter is:

[0070]

[0071] Among them, H' is the increased cutoff frequency of the output filter, H is the current cutoff frequency of the output filter, B is the minimum unit fluctuation amplitude for determining the cutoff frequency of the output filter, and h is the cutoff frequency of the output filter when the average fluctuation amplitude of the output voltage is the minimum unit fluctuation amplitude.

[0072] In practice, the value of B is generally 5V to 7V, and preferably, the preferred embodiment of B is 6V.

[0073] In implementation, the optional range of the value of h is [7kHz, 9kHz]. Preferably, when the cutoff frequency of the output filter is less than 8kHz, the probability of electromagnetic interference may increase. Therefore, the preferred embodiment of h is 8kHz.

[0074] For example, if an AC / DC switching power supply is used, where H = 6kHz and P = 6V, we can calculate

[0075]

[0076] In implementation, the switching power supply of the present invention determines the cutoff frequency of the output filter by setting a preset first fluctuation amplitude and a preset second fluctuation amplitude. Since a fault in a switching tube in the switching power supply may cause the switching frequency to change, causing power supply fluctuations, thereby increasing the possibility of electromagnetic interference, by increasing the cutoff frequency of the output filter, the filter can respond more quickly to high-frequency fluctuations in the power supply, reducing the impact of the switching frequency on the output, and further improving the operating stability of the AC / DC switching power supply.

[0077] Specifically, the average fluctuation amplitude of the output voltage is the average value of the difference between the maximum output voltage and the minimum output voltage in a number of power supply cycles.

[0078] Specifically, the control module obtains the temperature of the surface of the AC / DC switching power supply within a single operating cycle, and calculates the temperature increase rate of the surface of the AC / DC switching power supply. If the temperature increase rate of the surface of the AC / DC switching power supply is greater than a preset increase rate, it is further determined that the temperature of the AC / DC switching power supply is in an unstable state, and the delayed startup time of the AC / DC switching power supply is reduced.

[0079] It can be understood that the two intervals corresponding to the preset increase rate Y0 correspond to two situations. The first interval is Y≤Y0, corresponding to the situation where the stable state of the temperature of the AC / DC switching power supply meets the requirements; the second interval is Y>Y0, corresponding to the situation where the switching power supply runs at a high load for a long time, causing the internal components to generate more heat in the overload state, causing the temperature of the switching power supply to rise. In practice, the range of Y0 is generally [1.5℃ / h, 2.5℃ / h].

[0080] Preferably, the preset increase rate Y0 is 2° C. / h.

[0081] Specifically, the temperature rise rate of the surface of the AC / DC switching power supply is recorded as Y.

[0082] Specifically, the calculation formula for the temperature rise rate of the AC / DC switching power supply surface is:

[0083]

[0084] Wherein, Y is the temperature rise rate of the surface of the AC / DC switching power supply, K1 is the temperature of the surface of the AC / DC switching power supply at the end of a single operation cycle, K2 is the temperature of the surface of the AC / DC switching power supply at the initial moment of a single operation cycle, and T is the duration of a single operation cycle.

[0085] In implementation, the switching power supply of the present invention further determines the stable state of the temperature of the AC / DC switching power supply by setting a preset increase rate, thereby reducing the impact of the reduced operating stability of the AC / DC switching power supply due to inaccurate further determination of the stable state of the temperature of the AC / DC switching power supply, and further improving the operating stability of the AC / DC switching power supply.

[0086] Specifically, the reduction range of the delayed startup time of the AC / DC switching power supply is determined by the difference between the temperature increase rate of the surface of the AC / DC switching power supply and a preset increase rate.

[0087] Specifically, the calculation formula for the reduced delayed startup time of the AC / DC switching power supply is:

[0088]

[0089] Among them, L' is the delayed start-up time of the AC / DC switching power supply after reduction, L is the delayed start-up time of the current AC / DC switching power supply, C is the minimum unit increase rate for determining the delayed start-up time of the AC / DC switching power supply, and l is the delayed start-up time of the AC / DC switching power supply when the temperature increase rate on the surface of the AC / DC switching power supply is the minimum unit increase rate.

[0090] In practice, the value of C is generally 2°C / h to 4°C / h. Preferably, the preferred embodiment of C is 3°C / h.

[0091] In implementation, the optional value range of l is [0.3s, 0.5s]. Preferably, when the delayed startup time of the AC / DC switching power supply is greater than 0.4s, the temperature of the switching power supply may increase. Therefore, the preferred embodiment of l is 0.4s.

[0092] For example, if an AC / DC switching power supply is used, L = 0.6s, Y = 5°C / h, then we can calculate

[0093]

[0094] In implementation, the switching power supply of the present invention determines the delayed startup time of the AC / DC switching power supply by setting a preset increase rate. Since the switching power supply operates at a high load for a long time, the internal components generate more heat in an overload state, causing the temperature of the switching power supply to rise. By reducing the delayed startup time of the AC / DC switching power supply, the high impact current generated instantly at startup is reduced, which helps to reduce component load and heat loss, and further improves the operating stability of the AC / DC switching power supply.

[0095] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. An AC / DC switching power supply, characterized in that: include: An input module, used for processing an AC signal input to the AC / DC switching power supply, including an input filter for filtering the AC signal and a rectifier bridge connected to the input filter for converting the AC signal into a DC signal; A conversion module, which is connected to the input module and is used to process the DC signal, including a switch tube connected to the rectifier bridge to convert the DC signal into a high-frequency pulse and a transformer connected to the switch tube to convert the input voltage into a required output voltage; an output module connected to the conversion module, comprising an output filter connected to the transformer for filtering the output voltage and a voltage stabilizer connected to the output filter for stabilizing the output voltage; A control module, which is respectively connected to the input module, the conversion module and the output module, is used to determine the operating stability of the AC / DC switching power supply according to the variance of the output current, so as to determine whether to determine the duty cycle of the AC / DC switching power supply or determine the cut-off frequency of the output filter according to the average fluctuation amplitude of the output voltage, and to determine the delayed start-up time of the AC / DC switching power supply according to the average fluctuation amplitude of the output voltage and the temperature rise rate of the surface of the AC / DC switching power supply.

2. The AC / DC switching power supply according to claim 1, characterized in that: The control module obtains the output current in a number of power supply cycles and calculates the variance of the output current. If the variance of the output current is greater than a preset first variance, it is determined that the operating stability of the AC / DC switching power supply does not meet the requirements.

3. The AC / DC switching power supply according to claim 2, characterized in that: When the variance of the output current is greater than the preset first variance and less than or equal to the preset second variance, the control module preliminarily determines that the environmental stability of the AC / DC switching power supply does not meet the requirements, and further determines whether the environmental stability of the AC / DC switching power supply meets the requirements based on the average fluctuation amplitude of the output voltage.

4. The AC / DC switching power supply according to claim 3, characterized in that: The control module increases the duty cycle of the AC / DC switching power supply when the variance of the output current is greater than the preset second variance; The increase range of the duty cycle of the AC / DC switching power supply is determined by the difference between the variance of the output current and a preset second variance.

5. The AC / DC switching power supply according to claim 4, characterized in that: The control module obtains the output voltage within several power supply cycles and calculates the average fluctuation amplitude of the output voltage. If the average fluctuation amplitude of the output voltage is greater than a preset first fluctuation amplitude, it is further determined that the environmental stability of the AC / DC switching power supply does not meet the requirements.

6. The AC / DC switching power supply according to claim 5, characterized in that: When the average fluctuation amplitude of the output voltage is greater than a preset second fluctuation amplitude, the control module preliminarily determines that the temperature of the AC / DC switching power supply is in an unstable state, and further determines whether the stable state of the temperature of the AC / DC switching power supply meets the requirements based on the temperature increase rate on the surface of the AC / DC switching power supply.

7. The AC / DC switching power supply according to claim 6, characterized in that: The control module increases the cutoff frequency of the output filter when the average fluctuation amplitude of the output voltage is greater than the preset first fluctuation amplitude and less than or equal to the preset second fluctuation amplitude; The increase range of the cut-off frequency of the output filter is determined by the difference between the average fluctuation range of the output voltage and the preset first fluctuation range.

8. The AC / DC switching power supply according to claim 7, characterized in that: The average fluctuation amplitude of the output voltage is the average value of the difference between the maximum output voltage and the minimum output voltage in a plurality of power supply cycles.

9. The AC / DC switching power supply according to claim 8, characterized in that: The control module obtains the temperature of the surface of the AC / DC switching power supply within a single operation cycle, and calculates the temperature increase rate of the surface of the AC / DC switching power supply. If the temperature increase rate of the surface of the AC / DC switching power supply is greater than a preset increase rate, it is further determined that the temperature of the AC / DC switching power supply is in an unstable state, and the delayed startup time of the AC / DC switching power supply is reduced.

10. The AC / DC switching power supply according to claim 9, characterized in that: The reduction range of the delayed startup time of the AC / DC switching power supply is determined by the difference between the temperature increase rate of the surface of the AC / DC switching power supply and the preset increase rate.

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