Small power high pf power supply

Abstract

The application discloses a small-wattage high-PF power supply, which comprises an AC-DC conversion module, a transformer, a voltage transformation control module and an output filter circuit. A power factor (PF) value calibration module is arranged in the voltage transformation controller. The power factor value calibration module is used for detecting the voltage phase of the input power supply, so as to calibrate the phase of the output pulse width modulation control signal. A logic control module is also arranged in the voltage transformation controller. One end of the logic control module is connected with the power factor value calibration module, so as to receive the PF value correction signal output by the power factor value calibration module. The logic control module is used for controlling the output of the pulse width modulation signal which is in phase with the input power supply, so as to reduce the phase difference between the input voltage and the input current, and realize high PH value. The special high-PH value chip is not needed, so that the circuit is small, the production cost is low, and the application requirements of small-wattage power supply are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power supply, in particular to a small-wattage high-PF-value power supply. BACKGROUND

[0002] The PF value refers to the power factor, which is the cosine value COS of the phase difference between the input voltage and the input current; wherein the power factor = active power / apparent power, and the square of the apparent power = the square of the active power + the square of the reactive power. Low PF value will increase the loss of the power grid, and the higher the PF value, the more power is saved; generally, the power factor is above 0.5 below 5W, and above 0.7 above 5W. The high power factor is generally PFC > 0.9. The general low power factor is generally 0.4-0.6, the valley PFC can reach 0.7-0.9, and the APFC is generally above 0.9. PFC refers to power factor correction. The power factor can measure the degree of effective use of electric power. The larger the power factor value, the higher the power utilization rate. A good power supply PF value can reach above 0.95. For example, in some application fields of power supply, especially in Europe / Australia / Korea, the power factor of the power supply is required to reduce the interference to the power grid.

[0003] In the prior art, a dedicated high-PF-value chip is mainly used to realize a small-wattage high-PF-value power supply. This implementation mode leads to a large circuit and high production cost, and is not suitable for the convenient and low-cost application requirements of small-wattage power supplies. SUMMARY

[0004] The present application aims to at least solve one of the technical problems in the related art. To this end, one object of the present application is to provide a small-wattage high-PF-value power supply.

[0005] In one aspect, to achieve the above object, the small-wattage high-PF-value power supply according to an embodiment of the present application comprises:

[0006] An AC / DC conversion module connected with an input AC to convert the input power supply into a first DC;

[0007] A transformer, one end of a primary coil of the transformer being connected with a first DC output end of the AC / DC conversion module;

[0008] A voltage conversion control module comprises a voltage conversion controller, a voltage conversion control end of the voltage conversion controller is connected with the other end of the primary coil through a switch tube to perform voltage pulse width modulation control on the first direct current; a power factor PF value calibration module is arranged in the voltage conversion controller, the power factor PF value calibration module is used to detect a voltage phase of the input power supply to calibrate a phase of an output pulse width modulation control signal; a logic control module is further arranged in the voltage conversion controller, one end of the logic control module is connected with the power factor PF value calibration module to receive a PF value correction signal output by the power factor PF value calibration module, and a control output end of the logic control module is connected with the other end of the primary coil of the transformer through an internal or external switch tube to perform switch control on the switch tube.

[0009] An output filter circuit is connected with the secondary coil of the transformer to convert the pulse width modulation direct current output by the transformer into stable low-voltage direct current and output.

[0010] Further, according to one embodiment of the present application, the small-wattage high-PF-value power supply comprises an input sampling circuit, the input sampling circuit comprises:

[0011] A resistor R21, one end of the resistor R21 is connected with one end of an auxiliary coil of the transformer, and the other end of the auxiliary coil is connected with a reference ground;

[0012] A resistor R26, the resistor R26 is connected with the other end of the resistor R21 through a resistor R28, the other end of the resistor R26 is connected with the reference ground, and the one end of the resistor R26 is further connected with an input voltage detection end of the voltage conversion controller;

[0013] The power factor PF value calibration module is connected with the input voltage detection end of the voltage conversion controller to detect a voltage phase of the input power supply.

[0014] Further, according to one embodiment of the present application, the voltage conversion controller is arranged with a transformer fault protection module, the transformer fault protection module is used to detect a current and / or a voltage of the transformer to perform fault protection when the transformer fails.

[0015] Further, according to one embodiment of the present application, the small-wattage high-PF-value power supply further comprises a current sampling circuit, the current sampling circuit comprises:

[0016] a resistor R32, one end of the resistor R32 is connected with a reference ground, the other end of the resistor R32 is connected with the other end of the transformer primary coil through the switch tube, and the other end of the resistor R32 is also connected with a current feedback end of the transformer control.

[0017] Further, according to one embodiment of the present application, a current detection module is arranged in the transformer control, the current detection module is connected with a current feedback end of the transformer control, and the current detection module is used for detecting a current of the transformer primary coil.

[0018] Further, according to one embodiment of the present application, an abnormal current protection module is arranged in the transformer control, the abnormal current protection module is connected with a current feedback end of the transformer control, the current detection module is used for detecting a current of the transformer primary coil, and fault protection is performed when the current is abnormal.

[0019] Further, according to one embodiment of the present application, a cycle-by-cycle current limiting protection module is further arranged in the transformer control, the cycle-by-cycle current limiting protection module is connected with a current detection end of the transformer control, and the maximum inductance current flowing through the switch tube is limited during each switch tube conduction.

[0020] Further, according to one embodiment of the present application, a harmonic distortion calibration module is arranged in the transformer control, the harmonic distortion calibration module is used for detecting a harmonic signal of input and output power supply electricity, and calibration of harmonic distortion of an output pulse width modulation control signal is performed.

[0021] Further, according to one embodiment of the present application, a high-voltage starting module is further arranged in the transformer control, the high-voltage starting module is connected with a power supply power supply end, and high-voltage input power supply is converted into a power supply power supply of the controller.

[0022] a chip power supply generation module, the chip power supply generation module is connected with the high-voltage starting module, and wide-range input power supply is converted into a power supply power supply of the controller.

[0023] Further, according to one embodiment of the present application, a fault protection module is further arranged in the transformer control, the fault protection module is connected with the logic control module, and a fault signal is output to the logic control module.

[0024] The fault protection module includes one or more of an overcurrent protection module, a short-circuit protection module, an over-temperature protection module, and an overvoltage and undervoltage protection module.

[0025] The small-wattage high PF value power supply provided by the embodiment of the present application has a power factor PF value calibration module in the voltage transformation controller, which is used to detect the voltage phase of the input power supply to calibrate the phase of the output pulse width modulation control signal; the voltage transformation controller also has a logic control module, one end of which is connected with the power factor PF value calibration module to receive the PF value correction signal output by the power factor PF value calibration module; the logic control module controls the output of the pulse width modulation signal in phase with the input power supply to realize high PH value with less phase difference between the input voltage and current, and without using a dedicated high PH value chip, so that the circuit is small and the production cost is low, which meets the convenient and low cost application requirements of small-wattage power supply. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The small-wattage high PF value power supply structure schematic diagram provided by the embodiment of the present application;

[0027] Figure 2 The internal circuit structure block diagram of the voltage transformation controller provided by the embodiment of the present application.

[0028] The purpose implementation, functional characteristics and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0029] In order to enable the persons skilled in the art to better understand the present application scheme, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Unless otherwise defined, all the technical and scientific terms used in the present application have the same meanings as those commonly understood by the persons skilled in the art belonging to the technical field of the present application. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments and are not intended to limit the present application.

[0030] In the present application, the term "embodiment" means that the specific features, structures or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The phrase appears in various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. The person skilled in the art explicitly and implicitly understands that the embodiments described in the present application can be combined with other embodiments.

[0031] Reference Figure 1 and Figure 2The embodiment of the present application provides a small power high PF value power supply, comprising: AC / DC conversion module, transformer, voltage control module and output filter circuit, the AC / DC conversion module is connected with input AC, to convert input power into first DC; through the AC / DC conversion module, the commercial AC can be converted into first DC, and the first DC is high voltage DC.

[0032] One end of the primary coil of the transformer is connected with the first DC output end of the AC / DC conversion module; through the transformer, the first DC after pulse width adjustment can be transformed and output, so that the high voltage DC is converted into low voltage DC output, to supply power for low voltage electrical equipment.

[0033] The voltage control module comprises a voltage controller, and the voltage control end of the voltage controller is connected with the other end of the primary coil through a switch tube, to control the pulse width modulation of the first DC; the voltage controller is arranged between the transformer and reference ground, so that the conduction between the transformer and reference ground can be controlled, and the pulse width modulation of the first DC of the primary coil of the transformer is realized.

[0034] The voltage controller is provided with a power factor PF value calibration module, the power factor PF value calibration module is used for detecting the voltage phase of the input power, to calibrate the phase of the output pulse width modulation control signal; the phase information of the voltage of the input power is acquired through the power factor PF value calibration module. According to the phase information of the voltage of the input power, the phase of the pulse width modulation signal is adjusted and controlled, so that the limit of the modulation pulse width signal and the phase of the input AC can remain consistent. On this basis, the phase difference between the current on the power supply circuit and the input voltage is reduced. Since the PF value is the power factor, the PF value refers to the cosine value COS of the phase difference between the input voltage and the input current; through the reduction of the phase difference between the current on the power supply circuit and the input voltage, the PF value is improved. Since the phase of the input power is directly acquired through the voltage controller to improve the PF value of the circuit, an additional special chip is not needed to provide the PF value, so that the power supply circuit is simpler, and the production cost is relatively lower.

[0035] The variable voltage controller is further provided with a logic control module, one end of the logic control module is connected with the power factor PF value calibration module to receive the PF value correction signal output by the power factor PF value calibration module, and the control output end of the logic control module is connected with the other end of the primary coil of the transformer through an internal or external switch tube to control the switch tube. The logic control module is used to generate a pulse width modulation signal, and the switch tube is used to pulse width modulate the direct current voltage of the primary coil of the transformer. The logic control module can receive the PF value correction signal output by the power factor PF value calibration module to timely adjust the pulse width modulation signal and ensure the consistency of the pulse width modulation signal and the phase of the input power supply.

[0036] The output filter circuit is connected with the secondary coil of the transformer to convert the pulse width modulated direct current output by the transformer into stable low-voltage direct current and output. The secondary coil of the transformer outputs pulse direct current after pulse width modulation and voltage transformation, and the input filter circuit can convert the pulse direct current into stable low-voltage direct current to supply power to the power consumption device.

[0037] The small-wattage high-PF-value power supply provided by the embodiment of the application is provided with a power factor PF value calibration module in the variable voltage controller, the power factor PF value calibration module is used to detect the voltage phase of the input power supply to calibrate the phase of the output pulse width modulation control signal, the variable voltage controller is further provided with a logic control module, one end of the logic control module is connected with the power factor PF value calibration module to receive the PF value correction signal output by the power factor PF value calibration module, and the control output end of the logic control module is connected with the other end of the primary coil of the transformer through an internal or external switch tube to control the switch tube. The logic control module is used to generate a pulse width modulation signal, and the switch tube is used to pulse width modulate the direct current voltage of the primary coil of the transformer. The logic control module can receive the PF value correction signal output by the power factor PF value calibration module to timely adjust the pulse width modulation signal and ensure the consistency of the pulse width modulation signal and the phase of the input power supply.

[0038] The small-wattage high-PF-value power supply comprises an input sampling circuit, the input sampling circuit comprises a resistor R21 and a resistor R26, one end of the resistor R21 is connected with one end of an auxiliary coil of the transformer, and the other end of the auxiliary coil is connected with a reference ground; the resistor R26 is connected with the other end of the resistor R21 through a resistor R28, the other end of the resistor R26 is connected with the reference ground, and the one end of the resistor R26 is further connected with an input voltage detection end of the variable voltage controller; the resistor R21 and the resistor R26 constitute a voltage dividing circuit, the voltage of the auxiliary coil is divided and then fed back to the input voltage detection end of the variable voltage controller to meet the voltage sampling requirement of the variable voltage controller.

[0039] The power factor PF value calibration module is connected with the input voltage detection end of the transformer control device to detect the voltage phase of the input power supply. The power factor PF value calibration module only needs to detect the voltage phase of the auxiliary coil of the transformer for one cycle through voltage sampling, and the phase relationship of the voltage of the auxiliary coil can be obtained. The auxiliary coil of the transformer is set in phase with the primary coil, so that the phase of the input power supply can be obtained.

[0040] The transformer control device is provided with a transformer fault protection module. The transformer fault protection module is used to detect the current and / or voltage of the transformer to perform fault protection when the transformer fails. The transformer fault protection module is connected with the input voltage detection end of the transformer control device. The voltage and / or current of the transformer are obtained through primary side voltage feedback. When the transformer is designed unreasonably or fails due to other reasons, the input voltage detection end of the transformer control device can be used to detect the failure of the transformer and obtain a transformer fault signal when the transformer fails. The fault signal is output to the logic control module to obtain the transformer fault signal and perform corresponding fault processing.

[0041] The small-wattage high-PF-value power supply further comprises a current sampling circuit. The current sampling circuit comprises a resistor R32. One end of the resistor R32 is connected with the reference ground. The other end of the resistor R32 is connected with the other end of the primary coil of the transformer through the switch tube. The other end of the resistor R32 is also connected with the current feedback end of the transformer control device. The current on the primary coil of the transformer and the switch tube can be sampled through the resistor R32 and output to the current feedback end of the transformer control device.

[0042] The transformer control device is provided with a current detection module. The current detection module is connected with the current feedback end of the transformer control device. The current detection module is used to detect the current of the primary coil of the transformer. Since the feedback value of the primary current is in a certain proportional relationship with the output current of the second direct current, the output current of the second direct current can be obtained after the current detection module obtains the current of the primary coil. In addition, the current component information of the circuit can also be obtained through the current detection module.

[0043] The transformer control device is provided with an abnormal current protection module. The abnormal current protection module is connected with the current feedback end of the transformer control device. The current detection module is used to detect the current of the primary coil of the transformer and perform fault protection when the current is abnormal. When the output current value of the second direct current is abnormal, the pulse width of the pulse width modulation signal is adjusted in time to ensure the stability of the output current or disconnect the output power supply when overcurrent occurs.

[0044] The variable voltage controller further comprises a cycle-by-cycle current limiting protection module connected to the current detection terminal of the variable voltage controller to limit the maximum inductive current flowing through the switch tube during each conduction of the switch tube. The PWM IC variable voltage controller limits the maximum inductive current flowing through the MOSFET switch tube during each conduction of the power MOSFET switch tube through the cycle-by-cycle current limiting protection module. The power MOSFET is immediately turned off when the voltage on the sampling resistor exceeds the peak current reference Vcs_0cp, thereby ensuring the maximum peak current of the circuit and ensuring the circuit in a safe current state to avoid outputting excessive current to cause circuit failure and setting off the machine.

[0045] The variable voltage controller further comprises a harmonic distortion calibration module for detecting the harmonic signal of the input and output power supply to calibrate the harmonic distortion of the output pulse width modulation control signal. The input power supply signal and the output power supply signal are obtained through the harmonic distortion calibration module, and when it is found that the output power supply signal has more harmonic components,

[0046] The variable voltage controller further comprises a high-voltage starting module connected to the power supply terminal to convert the high-voltage input power supply into the power supply of the controller. The high-voltage starting module converts the input high-voltage direct current into the power supply VCC of the power supply controller and supplies power to the power supply controller when the power supply controller starts working. The high-voltage starting module is turned off after the power supply controller is started, and the auxiliary coil of the transformer supplies power. In addition, the starting power voltage can be introduced through the collector terminal of the power tube and used as the starting power voltage after being pressed by internal resistors, thereby reducing the external resistors of the starting circuit.

[0047] The chip power supply generation module is connected to the high-voltage starting module to convert the wide-range input power supply into the power supply of the controller. The chip power supply generation module supplies power voltage to the power supply controller, and when the secondary output voltage is 0V, the power supply controller IC is powered by the built-in high-voltage starting module 401. The design of the power supply controller IC has a wide VCC power supply range of 5-50V to ensure that the output constant voltage of the power supply is CV wide range.

[0048] The voltage control device further comprises a fault protection module connected to the logic control module to output a fault signal to the logic control module; the fault protection module comprises one or more of an overcurrent protection module, a short circuit protection module, an overtemperature protection module and an overvoltage / under-voltage protection module. The abnormal protection module can acquire various abnormal conditions of the power supply circuit and output a fault abnormal signal to the logic control module, and the logic control module can perform corresponding protection processing on each fault after receiving the fault abnormal signal to ensure the safety of the power supply circuit.

[0049] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0050] The above only describes the preferred embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made by using the content of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A small wattage high PF value power supply, characterized by, The power supply comprises: an AC-DC conversion module connected with an input AC power to convert the input power into a first DC power; a transformer, one end of a primary coil of the transformer being connected with a first DC power output end of the AC-DC conversion module; a voltage transformation control module comprising a voltage transformation controller, a voltage transformation control end of the voltage transformation controller being connected with the other end of the primary coil through a switch tube to perform voltage transformation pulse width modulation control on the first DC power; the voltage transformation controller is provided with a power factor PF value calibration module for detecting a voltage phase of the input power to calibrate a phase of an output pulse width modulation control signal; the voltage transformation controller is further provided with a logic control module, one end of the logic control module being connected with the power factor PF value calibration module to receive a PF value correction signal output by the power factor PF value calibration module, a control output end of the logic control module being connected with the other end of the primary coil of the transformer through an internal or external switch tube to perform switch control on the switch tube; an output filter circuit connected with a secondary coil of the transformer to convert a pulse width modulation DC power output by the transformer into stable low-voltage DC power and output the same; the voltage transformation controller is provided with a transformer fault protection module for detecting a current and / or a voltage of the transformer to perform fault protection when the transformer fails; The small-wattage high-PF power supply further comprises an input sampling circuit, which comprises: a resistor R21, one end of the resistor R21 being connected with one end of an auxiliary coil of the transformer, the other end of the auxiliary coil being connected with a reference ground; a resistor R26, the other end of the resistor R26 being connected with the other end of the resistor R21 through a resistor R28, the one end of the resistor R26 being connected with an input voltage detection end of the voltage transformation controller, the other end of the resistor R26 being connected with the reference ground; the power factor PF value calibration module is connected with the input voltage detection end of the voltage transformation controller to detect a voltage phase of the input power.

2. The low-power high PF power supply according to claim 1, characterized by The power supply further comprises a current sampling circuit, which comprises: a resistor R32, one end of the resistor R32 being connected with the reference ground, the other end of the resistor R32 being connected with the other end of the primary coil of the transformer through the switch tube, the other end of the resistor R32 being further connected with a current feedback end of the voltage transformation controller.

3. The low-power high PF power supply according to claim 2, characterized by The voltage transformation controller is provided with a current detection module, the current detection module being connected with the current feedback end of the voltage transformation controller, the current detection module being used to detect a current of the primary coil of the transformer.

4. The low-power high PF power supply according to claim 3, characterized by The voltage transformation controller is provided with an abnormal current protection module, the abnormal current protection module being connected with the current feedback end of the voltage transformation controller, the current detection module being used to detect a current of the primary coil of the transformer and perform fault protection when the current amount is abnormal.

5. The low-power high PF power supply according to claim 2, wherein The variable voltage controller is also provided with a cycle-by-cycle current limiting protection module, which is connected with the current detection end of the variable voltage controller, so as to limit the maximum inductive current flowing through the switch tube during each time the switch tube is turned on.

6. The low-power high PF power supply according to claim 1, characterized by The variable voltage controller is also provided with a harmonic distortion calibration module, which is used to detect the harmonic signals of the input power supply and the output power supply, so as to calibrate the harmonic distortion of the output pulse width modulation control signal.

7. The low-power high PF power supply according to claim 1, wherein The variable voltage controller is also provided with a high-voltage starting module, which is connected with the power supply end, so as to convert the high-voltage input power supply into the power supply of the controller. The chip power supply generation module is connected with the high-voltage starting module, so as to convert the wide-range input power supply into the power supply of the controller.

8. The low-power high PF power supply according to any one of claims 1 to 7, characterized by, The variable voltage controller is also provided with a fault protection module, which is connected with the logic control module, so as to output a fault signal to the logic control module. The fault protection module includes one or more of an overcurrent protection module, a short-circuit protection module, an over-temperature protection module, and an overvoltage and undervoltage protection module.

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