AC / DC Charger

Abstract

The present application relates to an AC / DC charger. The AC / DC charger includes a PFC main converter, a DC / DC auxiliary converter, a PFC controller, and a DC / DC controller; the PFC main converter includes a main output end and a DC output end, the DC output end is connected to the auxiliary input end of the DC / DC auxiliary converter, and the main output end is connected in series with the auxiliary output end of the DC / DC auxiliary converter to form a total output end; the control end of the PFC controller is connected to the PFC main converter, and the DC / DC controller includes a voltage control loop and a current control loop; the output ends of the voltage control loop and the current control loop are respectively connected to the control end of the DC / DC controller, and the control end of the DC / DC controller is connected to the DC / DC auxiliary converter. The PFC controller and the DC / DC controller are used to control the output voltages of the PFC main converter and the DC / DC auxiliary converter, so that the total output end outputs lower ripple and the conversion efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of circuit technologies, and in particular, to an Alternating Current to Direct Current (AC / DC) charger. Background Art

[0002] AC / DC chargers are widely used in various chargers, such as mobile phone chargers, PD chargers, electric forklift chargers, battery car chargers, drone chargers, robot chargers, etc.

[0003] Generally, AC / DC chargers include single-stage and multi-stage structures. A single-stage AC / DC charger cannot simultaneously achieve a high input power factor and a low output ripple. Therefore, in the industry, two-stage AC / DC cascaded structures are generally widely used in small-probability chargers and industrial equipment chargers. A two-stage AC / DC charger can achieve a high power factor and reduce the output ripple voltage or current. However, the AC input needs to go through two-stage full-power conversion to obtain the total output, and its conversion efficiency is the product of the conversion efficiencies of the two converters, inevitably generating more power consumption, thus resulting in a low overall conversion efficiency. Summary of the Invention

[0004] In view of the above deficiencies of the prior art, the purpose of this application is to provide an AC / DC charger, aiming to solve the problem of being unable to achieve both high conversion efficiency and low output ripple.

[0005] An embodiment of this application provides an AC / DC charger, which is characterized by including: a power factor correction (PFC) main converter, a DC / DC auxiliary converter, a PFC controller, and a DC / DC controller;

[0006] The PFC main converter includes a main output end and a DC output end. The DC output end is connected to the auxiliary input end of the DC / DC auxiliary converter, and the main output end is connected in series with the auxiliary output end of the DC / DC auxiliary converter to form a total output end;

[0007] The control end of the PFC controller is connected to the PFC main converter. The DC / DC controller includes a voltage control loop and a current control loop; the output ends of the voltage control loop and the current control loop are respectively connected to the control end of the DC / DC controller, and the control end of the DC / DC controller is connected to the DC / DC auxiliary converter;

[0008] The PFC main converter outputs a main output voltage through the main output terminal; the PFC main converter transmits the output DC output voltage to the auxiliary input terminal of the DC / DC auxiliary converter through the DC output terminal; the DC / DC auxiliary converter processes the DC output voltage to obtain an auxiliary output voltage, and the ripple of the auxiliary output voltage is opposite in phase to the ripple of the main output voltage, and the auxiliary output voltage is output through the auxiliary output terminal;

[0009] After receiving the main output voltage and the auxiliary output voltage, the total output terminal forms a total output voltage and an output total current; the PFC controller samples a first feedback voltage and uses the first feedback voltage to control the input voltage of the PFC main converter to be the same as the input current frequency and in the same phase; the voltage control loop samples a second feedback voltage and uses the second feedback voltage to control the ripple of the auxiliary output voltage output by the auxiliary output terminal of the DC / DC auxiliary converter to be opposite in phase to the ripple of the main output voltage; the current control loop samples the total current and uses the total current to control the DC / DC auxiliary converter;

[0010] The first feedback voltage includes one of the main output voltage and the auxiliary output voltage, and the second feedback voltage includes the total output voltage.

[0011] In a possible implementation manner, the PFC main converter further includes a power conversion unit, a main power switch tube, and a voltage conversion unit.

[0012] The main power switch tube is connected between the output terminal of the power conversion unit and the input terminal of the voltage conversion unit, the control terminal of the main power switch tube is connected to the control terminal of the PFC controller, and the output terminal of the voltage conversion unit is connected to the main output terminal and the DC output terminal;

[0013] The PFC controller controls the conduction and cutoff of the main power switch tube;

[0014] When the main power switch tube is conducting, the power conversion unit provides electrical energy for the voltage conversion unit, and the voltage conversion unit stores electrical energy;

[0015] When the main power switch tube is cutoff, the power conversion unit stops providing electrical energy for the voltage conversion unit, and the voltage conversion unit releases electrical energy.

[0016] In a possible implementation manner, the voltage conversion unit includes a main winding and an auxiliary winding;

[0017] One end of the main winding is connected to one end of the main power switch tube, and the other end of the main winding is connected to the main output terminal; one end of the auxiliary winding is connected to one end of the main power switch tube, and the other end of the auxiliary winding is connected to the auxiliary input terminal;

[0018] The voltage conversion unit outputs the main output voltage to the main output terminal through the main winding; the voltage conversion unit outputs the DC output voltage to the DC output terminal through the auxiliary winding.

[0019] In a possible implementation manner, the PFC controller includes a sampling unit and an adjustment feedback unit;

[0020] The output terminal of the sampling unit is connected to the input terminal of the adjustment feedback unit, and the output terminal of the adjustment feedback unit is connected to the control terminal of the main power switch tube;

[0021] The sampling unit is configured to: sample the first feedback voltage; the adjustment feedback unit is configured to: generate a first switch tube drive signal based on the first feedback voltage; the first switch tube drive signal is used to control the main power switch tube.

[0022] In a possible implementation manner, the sampling unit includes a first sampling terminal, a second sampling terminal, and a third sampling terminal; the adjustment feedback unit includes: a first comparator, a second comparator, a third comparator, a first reference voltage source, a first sawtooth wave signal source, and a trigger;

[0023] The output terminal of the first reference voltage source is connected to the positive input terminal of the first comparator, and the first sampling terminal is connected to the negative input terminal of the first comparator; the output terminal of the first comparator is connected to the positive input terminal of the second comparator, and the negative input terminal of the second comparator is connected to the second sampling terminal; the output terminal of the second comparator is connected to the positive input terminal of the third comparator, the first sawtooth wave signal source is connected to the negative input terminal of the third comparator, the output terminal of the third comparator is connected to the first input terminal of the trigger, the third sampling terminal is connected to the second input terminal of the trigger, and the output terminal of the trigger is connected to the control terminal of the PFC controller;

[0024] The first comparator receives the first feedback voltage from the first sampling terminal and the first reference voltage signal from the first reference voltage source, compares the first feedback voltage with the first reference voltage, and forms a first voltage error signal;

[0025] The second comparator receives the switch tube voltage signal from the second sampling terminal and the first voltage error signal from the first comparator, compares the first voltage error signal with the switch tube voltage signal, and obtains the current control signal of the main power switch tube. The switch tube voltage signal is obtained by converting the current signal of the main power switch tube;

[0026] The third comparator receives the current control signal from the second comparator and the first sawtooth signal from the first sawtooth signal source, compares the control signal with the sawtooth signal, and obtains a stop pulse signal; The third sampling terminal samples the electric energy of the voltage conversion unit to form a start pulse signal;

[0027] The flip-flop receives the stop pulse signal and the start pulse signal, and generates the first switch tube drive signal based on the start pulse signal and the stop pulse signal. The first switch tube drive signal is used to control the conduction and disconnection of the main power switch tube.

[0028] In a possible implementation manner, the DC / DC auxiliary converter includes an auxiliary power switch tube, an inductor, and a rectifier diode;

[0029] One end of the auxiliary power switch tube is connected to one pole of the auxiliary input terminal of the DC / DC auxiliary converter, the other end of the auxiliary power switch tube is connected to one end of the inductor, the other end of the inductor is connected to one pole of the auxiliary output terminal, one end of the rectifier diode is connected between the other end of the auxiliary power switch tube and one end of the inductor, and the other end of the rectifier diode is connected between the other pole of the auxiliary input terminal of the DC / DC auxiliary converter and the other pole of the auxiliary output terminal;

[0030] When the auxiliary power switch tube is conducting, the rectifier diode is cut off, the auxiliary input terminal of the DC / DC auxiliary converter receives the DC output voltage, provides electric energy for the inductor, and the inductor stores electric energy;

[0031] When the auxiliary power switch tube is cut off, the rectifier diode is conducting, the inductor, the rectifier diode, and the auxiliary output terminal form a current loop, the inductor releases electric energy, provides electric energy for the auxiliary output terminal, and enables the auxiliary output terminal to output the auxiliary output voltage.

[0032] In a possible implementation manner, the DC / DC controller includes a fourth comparator, a fifth comparator, a sixth comparator, a current reference source, a second reference voltage source, a second sawtooth signal source, a current sampling terminal, a voltage sampling terminal, and a logical OR circuit. The fourth comparator, the fifth comparator, the current reference source, and the current sampling terminal constitute the current control loop, and the sixth comparator, the fifth comparator, the second reference voltage source, and the voltage sampling terminal constitute the voltage control loop;

[0033] The positive input terminal of the fourth comparator is connected to the output terminal of the current reference source, the negative input terminal of the fourth comparator is connected to the current sampling terminal, and the output terminal of the fourth comparator is connected to the first input terminal of the logical OR circuit; the positive input terminal of the sixth comparator is connected to the output terminal of the second reference voltage source, the negative input terminal of the sixth comparator is connected to the voltage sampling terminal, and the output terminal of the sixth comparator is connected to the second input terminal of the logical OR circuit; the output terminal of the logical OR circuit is connected to the positive input terminal of the fifth comparator, the negative input terminal of the fifth comparator is connected to the output terminal of the second sawtooth signal source, and the output terminal of the fifth comparator is connected to the control terminal of the DC / DC controller;

[0034] The fourth comparator receives a current feedback signal from the current sampling terminal and a current reference signal from the current reference source. After comparing the current reference signal with the current feedback signal, a current error signal is formed;

[0035] The sixth comparator receives a second feedback voltage from the voltage sampling terminal and a second reference voltage signal from the second reference voltage source. After comparing the second feedback voltage with the second reference voltage signal, a second voltage error signal is formed;

[0036] The fifth comparator receives the current error signal or the second voltage error signal and a sawtooth signal from the sawtooth signal source. After comparing the sawtooth signal with the current error signal or the second voltage error signal, a second switching tube drive signal is formed, and the second switching tube drive signal is used to control the conduction and disconnection of the auxiliary power switching tube.

[0037] In a possible implementation manner, the logical OR circuit includes a first diode and a second diode;

[0038] The anode of the first diode is connected to the output terminal of the logical OR circuit, and the cathode of the first diode is connected to the first input terminal of the logical OR circuit;

[0039] The anode of the second diode is connected between the anode of the first diode and the output terminal of the logic OR circuit, and the cathode of the second diode is connected to the second input terminal of the logic OR circuit.

[0040] In a possible implementation, the voltage stress of the DC / DC auxiliary converter is less than a first threshold, and the current stress of the DC / DC auxiliary converter is less than a second threshold.

[0041] In a possible implementation, the PFC controller includes a first communication unit, the DC / DC controller includes a second communication unit, and the first communication unit establishes a communication connection with the second communication unit.

[0042] In a possible implementation, the PFC main converter includes one of a flyback converter, a boost converter, a buck converter, a buck-boost converter, a cuk converter, and a forward converter;

[0043] The DC / DC auxiliary converter includes one of a flyback converter, a boost converter, a buck converter, a buck-boost converter, a cuk converter, a forward converter, a bridge converter, a push-pull converter, a single-ended primary inductor converter, and an LLC resonant converter.

[0044] In a possible implementation, the control mode of the PFC controller includes one of a current critical conduction mode, a discontinuous conduction mode, and a critical conduction mode.

[0045] In a possible implementation, the PFC controller and the DC / DC controller are integrated into one or more analog chips.

[0046] In the embodiment of the present application, the main output voltage output by the PFC main converter and the auxiliary output voltage output by the DC / DC auxiliary converter constitute the total output voltage. Only a part of the output power undergoes two-stage conversion, thereby improving the conversion efficiency of the AC / DC charger. The PFC controller samples and feeds back the main output voltage or the total output voltage. While implementing the closed-loop control of the main output voltage or the total output voltage, it controls the input current and input voltage of the PFC main converter to be sinusoidal waves with the same frequency and the same phase, so as to achieve power factor correction and a higher power factor, and achieve zero pollution to the power grid. The DC / DC controller samples and feeds back the second feedback voltage, and closes the loop to control the second feedback voltage according to the change of the second feedback voltage. While implementing the closed-loop control of the second feedback voltage, it indirectly controls the ripples of the main output voltage and the auxiliary output voltage to be inversely superimposed and cancel each other out, realizing a lower ripple of the total output voltage. Description of the Drawings

[0047] Figure 1 It is a schematic structural diagram of an AC / DC charger provided by an embodiment of the present application;

[0048] Figure 2 This is a schematic diagram of another AC / DC charger provided by an embodiment of the present application;

[0049] Figure 3 This is a schematic diagram of another AC / DC charger provided by an embodiment of the present application;

[0050] Figure 4 This is a schematic diagram of another AC / DC charger provided by an embodiment of the present application;

[0051] Figure 5 This is a schematic diagram of a step-down PFC main converter provided by an embodiment of the present application;

[0052] Figure 6 This is a schematic diagram of a boost PFC main converter provided by an embodiment of the present application;

[0053] Figure 7 This is a schematic diagram of a buck-boost PFC main converter provided by an embodiment of the present application;

[0054] Figure 8 This is a schematic diagram of a boost DC / DC auxiliary converter provided by an embodiment of the present application;

[0055] Figure 9 This is a schematic diagram of a buck-boost DC / DC auxiliary converter provided by an embodiment of the present application;

[0056] Figure 10 This is a schematic diagram of a negative voltage step-down DC / DC auxiliary converter provided by an embodiment of the present application;

[0057] Figure 11 This is a schematic diagram of a flyback DC / DC auxiliary converter provided by an embodiment of the present application.

[0058] Explanation of reference numerals:

[0059] PFC main converter 10, power conversion unit 11, voltage conversion unit 12, main winding 121, auxiliary winding 122, DC / DC auxiliary converter 20, PFC controller 30, DC / DC controller 40, AC power supply 50, storage battery 60, PFC main converter input ports 1, 2, main output ports 3, 4, DC output ports 5, 6, auxiliary output ports 7, 8. Detailed implementation manners

[0060] To facilitate the understanding of this application, the following will provide a more comprehensive description of this application with reference to the relevant drawings. The preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of this application more thorough and comprehensive.

[0061] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0063] The following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the drawings in the embodiments of this application.

[0064] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of an AC / DC charger provided for the embodiments of this application. As Figure 1 shown, the AC / DC charger includes a power factor correction (PFC) main converter 10, a direct current to direct current (DC / DC) auxiliary converter 20, a PFC controller 30, and a DC / DC controller 40.

[0065] The PFC main converter 10 includes a main output terminal (such as the ports 3 and 4 shown in Figure 1 ) and a DC output terminal (such as the ports 5 and 6 shown in Figure 1 ). The DC output terminal is connected to the auxiliary input terminal of the DC / DC auxiliary converter 20, and the main output terminal is connected in series with the auxiliary output terminal of the DC / DC auxiliary converter 20 (such as the ports 7 and 8 shown in Figure 1 ) to form a total output terminal.

[0066] The control terminal of the PFC controller 30 is connected to the PFC main converter 10. The DC / DC controller 40 includes a voltage control loop 41 and a current control loop 42. The output terminals of the voltage control loop 41 and the current control loop 42 are respectively connected to the control terminal of the DC / DC controller 40, and the control terminal of the DC / DC controller 40 is connected to the DC / DC auxiliary converter 20.

[0067] The PFC main converter 10 outputs the main output voltage Vo1 through the main output terminal. The PFC main converter 10 transmits the output DC output voltage to the auxiliary input terminal of the DC / DC auxiliary converter 20 through the DC output terminal. The DC / DC auxiliary converter 20 processes the DC output voltage to obtain the auxiliary output voltage Vo2. The ripple of the auxiliary output voltage Vo2 is opposite in phase to the ripple of the main output voltage Vo1, and the auxiliary output voltage Vo2 is output through the auxiliary output terminal.

[0068] After the main output voltage Vo1 and the auxiliary output voltage Vo2 are received at the total output terminal, the total output voltage Vo and the output total current Io are formed. The PFC controller 30 samples the first feedback voltage and uses the first feedback voltage to control the input voltage of the PFC main converter 10 to have the same frequency and phase as the input current. The voltage control loop 41 samples the second feedback voltage and uses the second feedback voltage to control the ripple of the auxiliary output voltage Vo2 output from the auxiliary output terminal of the DC / DC auxiliary converter 20 to be opposite in phase to the ripple of the main output voltage Vo1. The current control loop 42 samples the total current Io and uses the total current Io to control the DC / DC auxiliary converter 20.

[0069] The above first feedback voltage includes one of the main output voltage Vo1 and the auxiliary output voltage Vo2, and the above second feedback voltage includes the total output voltage Vo.

[0070] Specifically, the input terminals of the PFC main converter 10 (such as Figure 1 the shown ports 1 and 2) are connected to the output terminal of the AC power supply 50, and the AC power supply 50 provides alternating current for the PFC main converter 10. After the PFC main converter 10 performs power conversion and voltage conversion on the alternating current, it outputs the main output voltage Vo1 through the main output terminal and outputs the DC voltage through the DC output terminal, transmits the main output voltage Vo1 to the total output terminal, and outputs the DC output voltage to the auxiliary input terminal of the DC / DC auxiliary converter 20. After receiving the DC output voltage, the DC / DC auxiliary converter 20 performs conversion on it to obtain the auxiliary output voltage Vo2, and transmits the auxiliary output voltage Vo2 to the total output terminal through the auxiliary output terminal of the DC / DC auxiliary converter 20. After the total output terminal receives the main output voltage Vo1 and the auxiliary output voltage Vo2, the total output voltage Vo is formed to charge the storage battery 60.

[0071] The control terminal of the PFC controller 30 is connected to the PFC main converter 10. The input terminal of the PFC controller 30 can be connected to the main output terminal or the total output terminal to sample the first feedback voltage and control the PFC main converter 10 based on the first feedback voltage. The PFC main converter 10 and the PFC controller 30 form a first feedback loop. The control terminal of the DC / DC controller 40 is connected to the DC / DC auxiliary converter 20. The input terminal of the DC / DC controller 40 can be connected to the main output terminal, the auxiliary output terminal, or the total output terminal to sample the second feedback voltage and control the DC / DC auxiliary converter 20 based on the second feedback voltage. The DC / DC auxiliary converter 20 and the DC / DC controller 40 form a second feedback loop.

[0072] It can be understood that the total output terminal is formed by connecting the main output terminal and the auxiliary output terminal in series. Therefore, the total output voltage Vo is the sum of the main output voltage Vo1 and the auxiliary output voltage Vo2. Since the power frequency ripple is an inherent characteristic of the main output voltage Vo1 and the auxiliary output voltage Vo2, by controlling the power frequency ripple of the auxiliary output voltage Vo2 output by the DC / DC auxiliary converter 20 through the DC / DC controller 40 to be opposite in phase to the power frequency ripple of the main output voltage Vo1, the power frequency ripples of the main output voltage Vo1 and the auxiliary output voltage Vo2 cancel each other out after being superimposed, resulting in a lower ripple of the total output voltage Vo.

[0073] The first feedback voltage includes one of the main output voltage Vo1 and the auxiliary output voltage Vo2. The PFC controller 30 can select to sample and feedback the main output voltage Vo1 or the auxiliary output voltage Vo2 through an electronic gating switch. The normal charging process of the storage battery 60 includes a constant current charging stage and a constant voltage charging stage. In the embodiment of the present application, the DC / DC controller can enable one of the voltage control loop 41 and the current control loop 42 through a logic OR circuit.

[0074] During the constant current charging stage, the logic OR circuit in the DC / DC controller enables the current control loop 42. The DC / DC controller 40 samples the total current Io and controls the output current of the DC / DC auxiliary converter 20 according to the change of the total current Io. Since the total output terminal is formed by the series connection of the main output terminal and the auxiliary output terminal, the current of the main output terminal is equal to the current of the auxiliary output terminal. By controlling the output current of the DC / DC auxiliary converter 20 through the DC / DC controller 40, the total current Io is controlled, so that the total current Io remains constant, that is, the charging current of the battery 60 is controlled to be a fixed value, realizing the closed-loop control of the total current Io. During the constant current charging stage, the electronic gating switch in the PFC controller 30 selects the auxiliary output voltage Vo2, that is, the PFC controller 30 samples the auxiliary output voltage Vo2 and controls the DC output voltage output by the PFC main converter 10 to be large enough based on the auxiliary output voltage Vo2. The DC / DC auxiliary converter is indirectly controlled through the feedback loop, so that the magnitude of the auxiliary output voltage is a fixed value. While realizing the closed-loop control of the auxiliary output voltage Vo2, the PFC controller 30 controls the input voltage of the PFC main converter 10 to be the same as the frequency and phase of the input current, so as to achieve power factor correction and a higher power factor.

[0075] Correspondingly, during the constant voltage charging stage, the electronic gating switch in the PFC controller 30 selects the main output voltage Vo1, that is, the PFC controller 30 samples the main output voltage Vo1 and controls the main output voltage Vo1 output by the PFC main converter 10 according to the change of the main output voltage Vo1. While realizing the closed-loop control of the main output voltage Vo1, the PFC controller 30 controls the input voltage of the PFC main converter 10 to be the same as the frequency and phase of the input current, so as to achieve power factor correction and a higher power factor. The logic OR circuit in the DC / DC controller 40 enables the current control loop 42. The DC / DC controller 40 samples the total output voltage Vo and controls the auxiliary output voltage Vo2 output by the DC / DC auxiliary converter 20 according to the change of the total output voltage Vo, thereby indirectly controlling the total output voltage, so that the total output voltage remains constant, that is, the charging voltage of the battery 60 is controlled to be a fixed value. Thus, the output ripple of the main output voltage Vo1 and the output ripple of the auxiliary output voltage Vo2 are indirectly controlled to be out of phase.

[0076] In the embodiment of the present application, the main output voltage Vo1 is greater than the auxiliary output voltage Vo2. The PFC main converter 10 provides most of the power for the battery 60, and the DC / DC auxiliary converter 20 provides a small part of the output power for the battery 60. Most of the output power undergoes single-stage power conversion, and only a small part of the power undergoes two-stage power conversion, improving the overall power conversion efficiency.

[0077] Specifically, assume that the conversion efficiency of the PFC main converter 10 is , the conversion efficiency of the DC / DC auxiliary converter 20 is , 、 、 are the output power of the PFC main converter 10, the output power of the DC / DC auxiliary converter 20, and the overall output power respectively. Then the overall efficiency is:

[0078]

[0079] Suppose , then:

[0080] Another supposition , then the overall conversion efficiency .

[0081] As can be seen from the above, when the output power ratio of the DC / DC auxiliary converter 20 is 10%, even if the conversion efficiency of the DC / DC auxiliary converter 20 is as low as 90%, the overall conversion efficiency is close to 99% of the conversion efficiency of the single-stage converter. Compared with the traditional two-stage converter, it has lower power loss and higher conversion efficiency.

[0082] In the embodiment of the present application, the PFC controller 30 controls the input voltage of the PFC main converter 10 to have the same frequency and phase as the input current to achieve power factor correction and a higher power factor, realizing zero pollution to the power grid. The DC / DC controller 40 indirectly controls the ripples of the main output voltage Vo1 and the auxiliary output voltage Vo2 to be anti-phase superimposed and cancel each other out, realizing a lower ripple of the total output voltage Vo. At the same time, during the process of charging the battery, most of the output power undergoes single-stage power conversion, and only a small part of the power undergoes two-stage power conversion, improving the overall power conversion efficiency.

[0083] In a possible implementation manner, please refer to Figure 2 , Figure 2 which is a schematic structural diagram of another AC / DC charger provided by the embodiment of the present application. As Figure 2 shown, the above-mentioned PFC main converter 10 further includes a power conversion unit 11, a main power switch Q1, and a voltage conversion unit 12.

[0084] The main power switch Q1 is connected between the power conversion unit 11 and the voltage conversion unit 12. The control end of the main power switch Q1 is connected to the control end of the PFC controller 30. The output end of the voltage conversion unit 12 is connected to the main output end and the DC output end.

[0085] Specifically, the PFC controller 30 samples the main output voltage Vo1 or the total output voltage Vo to form a first feedback signal. The PFC controller 30 generates a first switch tube drive signal based on the first feedback signal, and transmits the generated first switch tube drive signal to the control end of the main power switch tube Q1 through the control end of the PFC controller 30 to control the conduction and cut-off of the main power switch tube Q1.

[0086] When the main power switch tube Q1 is conducting, the power conversion unit 11 receives alternating current from the AC power supply, converts the alternating current, and provides electrical energy to the voltage conversion unit 12, and the voltage conversion unit 12 stores the electrical energy.

[0087] When the main power switch tube Q1 is cut off, the connection between the power conversion unit 11 and the voltage conversion unit 12 is disconnected, the power conversion unit 11 stops providing electrical energy to the voltage conversion unit 12, and the voltage conversion unit 12 releases the electrical energy.

[0088] In the embodiment of the present application, by controlling the conduction and cut-off of the main power switch tube Q1 by the PFC controller 30, while realizing the closed-loop control of the main output voltage Vo1 or the total output voltage Vo, through conventional control methods such as Discontinuous Conduction Mode (DCM), Critical Conduction Mode (CRM), or Continuous Conduction Mode (CCM) with a multiplier, the envelope waveform of the input current follows the power frequency sine wave of the input voltage and becomes a discontinuous, critical or continuous high-frequency varying current, so as to eliminate the current waveform distortion and phase change caused by the energy storage of capacitive elements and inductive elements in a conventional circuit without a power factor correction function, and after filtering by the input Electromagnetic Interference (EMI) filter, the input current has the same frequency and phase as the input voltage, realizing power factor correction and improving the power factor.

[0089] In a possible implementation manner, please refer to Figure 2 , the above voltage conversion unit 12 includes a main winding 121 and an auxiliary winding 122.

[0090] One end of the main winding 121 is connected to one end of the main power switch tube Q1, and the other end of the main winding 121 is connected to the main output end; one end of the auxiliary winding 122 is connected to one end of the main power switch tube Q1, and the other end of the auxiliary winding 122 is connected to the auxiliary input end;

[0091] The above voltage conversion unit 12 outputs the main output voltage Vo1 to the main output terminal through the main winding 121; the voltage conversion unit 12 outputs the DC output voltage Vo3 to the DC output terminal through the auxiliary winding 122.

[0092] The voltage conversion unit 12 may be a transformer or a dual-winding inductor L1 of a dual-winding type having a main winding 121 and an auxiliary winding 122.

[0093] The resistance of the main winding 121 is less than that of the auxiliary winding 122. Therefore, when the current is the same, the voltage of the main winding 121 is greater than that of the auxiliary winding 122, that is, the main output voltage Vo1 is greater than the auxiliary output voltage Vo2, and the output power of the main output terminal is greater than that of the auxiliary output terminal. Thus, the conversion efficiency can be better improved.

[0094] In a possible implementation manner, please refer to Figure 3 , the PFC controller 30 includes a first sampling unit 31 and a first conditioning feedback unit 32.

[0095] The output terminal of the first sampling unit 31 is connected to the input terminal of the first conditioning feedback unit 32, and the output unit of the first conditioning feedback unit 32 is connected to the control terminal of the main power switch Q1. The first sampling unit 31 is used for: sampling the first feedback voltage; the first conditioning feedback unit 32 is used for: generating a first switch driving signal based on the first feedback voltage; the first switch driving signal is used for controlling the conduction and cutoff of the main power switch Q1.

[0096] Specifically, the first feedback voltage may include one of the main output voltage Vo1 and the total output voltage Vo. The input terminal of the first sampling unit 31 may be connected to the main output terminal or the total output terminal to sample the first feedback voltage and then transmit the first sampled voltage to the first conditioning feedback unit 32. The first conditioning feedback unit 32 generates a first switch driving signal based on the first feedback voltage and transmits the first switch driving signal to the control terminal of the main power switch Q1 to control the conduction and cutoff of the main power switch Q1. The first sampling unit 31, the first conditioning feedback unit 32, the main power switch Q1, the voltage conversion unit 12, and the main output terminal or the total output terminal form a first feedback loop. By controlling the conduction or cutoff of the main power switch Q1 through the first feedback loop, the main output voltage Vo1 can be directly controlled, thereby indirectly controlling the total output voltage Vo to achieve closed-loop control of the main output voltage Vo1 or the total output voltage Vo.

[0097] In the embodiment of the present application, the PFC controller 30 controls the conduction and cutoff of the main power switch tube Q1 to achieve the closed-loop control of the main output voltage or the total output voltage. At the same time, the input current and the output current are controlled to be sinusoidal waves with the same frequency and the same phase, so as to achieve power factor correction and a higher power factor.

[0098] In a possible implementation manner, please refer to Figure 4 , the first sampling unit 31 includes a first sampling terminal a1, a second sampling terminal a2, and a third sampling terminal a3; the first conditioning feedback unit 32 includes: a first comparator U1, a second comparator U2, a third comparator U3, a first reference voltage source Vr1, a first sawtooth wave signal source Vramp1, and a trigger U4.

[0099] The output terminal of the first reference voltage source Vr1 is connected to the positive input terminal of the first comparator U1, and the first sampling terminal a1 is connected to the negative input terminal of the first comparator U1; the output terminal of the first comparator U1 is connected to the positive input terminal of the second comparator U2, and the negative input terminal of the second comparator U2 is connected to the second sampling terminal a2; the output terminal of the second comparator U2 is connected to the positive input terminal of the third comparator U3, the first sawtooth wave signal source Vramp1 is connected to the negative input terminal of the third comparator U3, the output terminal of the third comparator U3 is connected to the first input terminal of the trigger U4, the third sampling terminal a3 is connected to the second input terminal of the trigger U4, and the output terminal of the trigger U4 is connected to the control terminal of the main power switch tube Q1.

[0100] The first comparator U1 receives the first feedback voltage from the first sampling terminal a1 and the first reference voltage signal from the first reference voltage source Vr1, and compares the first feedback voltage with the reference voltage to form a first voltage error signal.

[0101] The second comparator U2 receives the switch tube voltage signal from the second sampling terminal a2 and the first voltage error signal from the first comparator U1, and compares the first voltage error signal with the switch tube voltage signal to obtain the current control signal of the main power switch tube Q1. The switch tube voltage signal is obtained by converting the current signal of the main power switch tube Q1.

[0102] The third comparator U3 receives the current control signal from the second comparator U2 and the first sawtooth wave signal from the first sawtooth wave signal source Vramp1, and compares the current control signal with the sawtooth wave signal to obtain a stop pulse signal; the third sampling terminal a3 samples the energy release signal of the voltage conversion unit 12 to form a start pulse signal.

[0103] The above-mentioned flip-flop U4 receives the above-mentioned stop pulse signal and the above-mentioned start pulse signal, generates the above-mentioned first switch tube drive signal based on the above-mentioned start pulse signal and the above-mentioned stop pulse signal, and the above-mentioned first switch tube drive signal is used to control the conduction and disconnection of the above-mentioned main power switch tube Q1.

[0104] Specifically, the first sampling terminal a1 can be directly connected to the main output terminal and the auxiliary output terminal to sample the main output voltage Vo1 and the auxiliary output voltage Vo2. The electronic gating switch S is used to select whether to feedback the main output voltage Vo1 or the auxiliary output voltage Vo2 to form the first feedback voltage. During the constant current charging stage of the normal charging process of the storage battery 60, the first sampling terminal a1 selects to feedback the auxiliary output voltage Vo2 through the electronic gating switch S. During the constant voltage charging stage, the first sampling terminal a1 selects to feedback the main output voltage Vo1 through the electronic gating switch S.

[0105] The second sampling terminal a2 can detect the current of the main power switch tube Q1 through the resistor Ri and convert it into a voltage signal to form a switch tube voltage signal; the third sampling terminal a3 can detect the energy release signal of the voltage conversion unit 12 through the resistor Rdem to form a start pulse signal. The first sampling terminal a1 transmits the sampled first feedback voltage to the inverting input terminal of the first comparator U1. The non-inverting input terminal of the first comparator U1 is connected to the first reference voltage source Vr1, and the first reference voltage source Vr1 transmits the first reference voltage to the non-inverting input terminal of the first comparator U1. The first comparator U1 compares the first feedback voltage and the first reference voltage to obtain a voltage error signal, and amplifies the voltage error signal and outputs it to the non-inverting input terminal of the second comparator U2. The second sampling terminal a2 transmits the switch tube voltage signal to the inverting input terminal of the second comparator U2 to control the peak current of the main power switch tube Q1. The second comparator U2 forms a current control signal of the main power switch tube Q1 after comparing the first voltage error signal and the switch tube voltage signal, and transmits the control signal to the non-inverting input terminal of the third comparator U3. The third comparator receives the standard sawtooth wave signal from the first sawtooth wave signal source Vramp1, compares the standard sawtooth wave signal with the control signal to form a stop pulse signal, and transmits the stop pulse signal to the first input terminal of the flip-flop U4. The third sampling terminal a3 transmits the start pulse signal to the second input terminal of the flip-flop U4. The flip-flop U4 generates a switch drive signal based on the start pulse signal and the stop pulse signal, and transmits the generated switch drive signal to the control terminal of the main power switch tube Q1 to control the conduction or cut-off of the main power switch tube Q1. The above-mentioned switch drive signal can be a pulse width modulation (PWM) switch drive signal, and the above-mentioned flip-flop can be a Reset-Set (RS) flip-flop.

[0106] In the embodiment of the present application, the magnitude of the reference voltage is constant. The PFC controller 30 controls the sampled main output voltage Vo1 or the total output voltage Vo to be equal to the reference voltage in real time through sampling, conditioning, and feedback, thereby realizing the closed-loop control of the main output voltage Vo1 or the total output voltage Vo. With the PFC controller 30 having the above structure, precise control of the PFC main converter 10 can be achieved, which is simple to manufacture, has a low cost, and also has a high control accuracy.

[0107] In a possible implementation manner, the control modes of the above PFC controller 30 include one of a critical conduction mode of current, a discontinuous conduction mode of current, and a continuous conduction mode of current.

[0108] In the critical conduction mode of current, the PFC controller 30 detects the energy release signal of the voltage conversion unit 12 through the third sampling terminal a3. After the end of the previous conduction cycle of the main power switch Q1 and before the next conduction cycle, the energy of the voltage conversion unit 12 is completely released, and the secondary side current of the auxiliary winding 122 decays to zero. The conduction frequency of the main power switch Q1 changes with the line voltage and the battery 60.

[0109] In the discontinuous conduction mode of current, the PFC controller 30 does not need to detect the energy release signal of the voltage conversion unit 12, and the conduction frequency of the main power switch Q1 changes with the magnitude of the input voltage. In the continuous conduction mode of current, the conduction frequency of the main power switch Q1 is constant, and the conduction duty cycle changes with the magnitude of the input voltage.

[0110] In the embodiment of the present application, different control modes can be selected according to actual needs, which can be adapted to different circuit structures to achieve power factor correction in each circuit.

[0111] In a possible implementation manner, please refer to Figure 4 , the DC / DC auxiliary converter 20 includes an auxiliary power switch Q2, an inductor L2, and a rectifier diode D7.

[0112] One end of the auxiliary power switch Q2 is connected to one pole of the auxiliary input terminal of the DC / DC auxiliary converter 20, the other end of the auxiliary power switch Q2 is connected to one end of the inductor L2, the other end of the inductor L2 is connected to port 7 of the above auxiliary output terminal, one end of the rectifier diode D7 is connected between the other end of the auxiliary power switch Q2 and one end of the inductor L2, and the other end of the rectifier diode D7 is connected between the other pole of the auxiliary input terminal of the DC / DC auxiliary converter 20 and port 8 of the auxiliary output terminal;

[0113] When the auxiliary power switch Q2 is conducting, the rectifier diode D7 is cut off, the auxiliary input terminal of the DC / DC auxiliary converter 20 receives the DC output voltage, provides electrical energy for the inductor L2, and the inductor L2 stores electrical energy.

[0114] When the auxiliary power switch transistor Q2 is turned off, the rectifier diode D7 conducts, and the inductor L2, the rectifier diode D7, and the auxiliary output terminal form a current loop. The inductor L2 releases electrical energy to provide electrical energy for the auxiliary output terminal, so that the auxiliary output terminal outputs the auxiliary output voltage Vo2.

[0115] Specifically, when the auxiliary power output switch transistor Q2 is turned on, the diode D7 is turned off, and the auxiliary input terminal of the DC / DC auxiliary converter 20 is connected to the inductor L2 to provide electrical energy for the inductor L2. While the inductor L2 stores electrical energy, it outputs electrical energy to the auxiliary output terminal, so that the auxiliary output terminal outputs the auxiliary output voltage Vo2. When the auxiliary power switch transistor Q2 is turned off, the diode D7 conducts, and the inductor L2, the auxiliary output terminal, and the diode D7 form a current loop. The inductor L2 releases electrical energy to provide electrical energy for the auxiliary output port, so that the auxiliary output terminal outputs the auxiliary output voltage.

[0116] In the embodiment of the present application, the control of the auxiliary output voltage can be realized by controlling the conduction and cut-off of the auxiliary power switch transistor, and the production is simple and the cost is low.

[0117] In a possible implementation manner, please refer to Figure 4 As shown in the figure, the above-mentioned DC / DC controller 40 includes a fourth comparator U5, a fifth comparator U6, a sixth comparator U7, a current reference source Iref, a second reference voltage source Vr2, a second sawtooth signal source Vramp2, a current sampling terminal b1, a voltage sampling terminal b2, and a logic OR circuit 43. The fourth comparator U5, the fifth comparator U6, the current reference source Iref, and the current sampling terminal b1 constitute a current control loop 42, and the sixth comparator U7, the fifth comparator U6, and the second reference voltage source Vr2 constitute a voltage control loop 41.

[0118] The positive input terminal of the fourth comparator U5 is connected to the output terminal of the current reference source Iref, the negative input terminal of the fourth comparator U5 is connected to the current sampling terminal b1, and the output terminal of the fourth comparator U5 is connected to the first input terminal of the logic OR circuit 43; the positive input terminal of the sixth comparator U7 is connected to the output terminal of the second reference voltage source Vr2, the negative input terminal of the sixth comparator U7 is connected to the voltage sampling terminal b2, and the output terminal of the sixth comparator U7 is connected to the second input terminal of the logic OR circuit 43; the output terminal of the logic OR circuit 43 is connected to the positive input terminal of the fifth comparator U6, the negative input terminal of the fifth comparator U6 is connected to the output terminal of the second sawtooth signal source Vramp2, and the output terminal of the fifth comparator U6 is connected to the control terminal of the DC / DC controller 40.

[0119] The fourth comparator U5 receives the current feedback signal from the current sampling terminal b1 and the reference current from the current reference source Iref. After comparing the reference current with the current feedback signal, a current error signal is formed.

[0120] The sixth comparator U7 receives the second feedback voltage from the voltage sampling terminal b2 and the second reference voltage from the second reference voltage source Vr2, compares the second feedback voltage with the reference voltage, and forms a second voltage error signal.

[0121] The fifth comparator U6 receives the above-mentioned current error signal or the above-mentioned second voltage error signal and the sawtooth wave signal from the second sawtooth wave signal source Vramp2, compares the sawtooth wave signal with the current error signal or the second voltage error signal, and forms a second switch tube drive signal, and the second switch tube drive signal is used to control the conduction and disconnection of the auxiliary power switch tube Q2.

[0122] Specifically, the above-mentioned current sampling terminal b1 can detect the total current Io through the resistor Ro, that is, detect the charging current of the storage battery 60, convert the detected total current Io into a voltage signal to form a current feedback signal Ios, and transmit the current feedback signal Ios to the fourth comparator U5. The current reference source Iref transmits a current reference signal to the fourth comparator U5. The fourth comparator U5 compares the current feedback signal and the current reference signal to obtain a current error signal, amplifies the current error signal and transmits it to the first input terminal of the logic OR circuit 43.

[0123] The above-mentioned voltage sampling terminal b2 can be connected to the total output terminal to sample the main output voltage Vo to form a second feedback voltage Vos, and transmit the second feedback voltage Vos to the sixth comparator U7. The second reference voltage source Vr2 transmits a second reference voltage signal to the sixth comparator U7. The sixth comparator U7 compares the second voltage feedback signal Vos and the second reference voltage signal to form a second voltage error signal, and transmits the second voltage error signal to the second input terminal of the logic OR circuit 43.

[0124] The above-mentioned logic OR circuit 43 can automatically enable one of the current control loop 42 and the voltage control loop 41 according to the magnitudes of the above-mentioned current error signal and the above-mentioned voltage error signal, so that the fifth comparator U6 receives the current error signal or the voltage error signal. The second sawtooth wave signal source Vramp2 transmits a second sawtooth wave signal to the fifth comparator U6, and the fifth comparator compares the received current error signal or voltage error signal with the second sawtooth wave signal to form a second switch drive signal, and the second switch drive signal is used to control the conduction and cut-off of the auxiliary power switch tube Q2.

[0125] During the constant current charging stage of the normal charging process of the storage battery 60, the logic OR circuit 43 enables the current control loop 42. The fifth comparator U6 receives the current error signal and compares the current error signal with the second sawtooth wave signal to form a second switch driving signal. The second switch driving signal is used to control the conduction and cut-off of the auxiliary power switch tube Q2 to control the output current of the DC / DC auxiliary converter 20, thereby realizing the closed-loop control of the total current Io, that is, realizing the closed-loop control of the charging current of the storage battery 60.

[0126] During the constant voltage charging stage of the normal charging process of the storage battery 60, the logic OR circuit 43 enables the voltage control loop 41. The fifth comparator U6 receives the voltage error signal and compares the voltage error signal with the second sawtooth wave signal to form a second switch driving signal. The second switch driving signal is used to control the conduction and cut-off of the auxiliary power switch tube Q2 to control the auxiliary output voltage Vo2 output by the DC / DC auxiliary converter 20, thereby indirectly controlling the main output voltage Vo and realizing the closed-loop control of the main output voltage Vo, that is, realizing the closed-loop control of the charging voltage of the storage battery 60.

[0127] In the embodiment of the present application, the DC / DC controller 40 performs fast loop control, and the frequency of the output second switch driving signal is greater than the frequency of the first switch tube driving signal. The DC / DC auxiliary converter 20 quickly responds to the second switch driving signal, so that the total circuit Io is equal to the reference current in real time during the constant current charging stage, and the total output voltage Vo is equal to the second reference voltage in real time during the constant voltage charging stage, realizing the closed-loop control of the charging current or charging voltage of the storage battery 60. The frequency of the above second switch driving signal can be controlled by the second sawtooth wave signal source Vramp2. Using the DC / DC controller 40 with the above structure to control the DC / DC auxiliary converter 20 can accurately control the charging current or charging voltage of the storage battery 60.

[0128] In a possible implementation manner, please refer to Figure 4 , the above logic OR circuit 43 includes a first diode Di and a second diode Dv.

[0129] The anode of the first diode Di is connected to the output end of the logic OR circuit 43, and the cathode of the first diode Di is connected to the first input end of the logic OR circuit.

[0130] The anode of the second diode Dv is connected between the anode of the first diode Di and the output end of the logic OR circuit 43, and the cathode of the second diode Dv is connected to the second input end of the logic OR circuit 43.

[0131] Specifically, when the current feedback signal is greater than the current reference signal, the fourth comparator U5 outputs a low level, the first diode Di conducts, and the logic OR circuit 43 enables the current control loop 42. When the current feedback signal is less than the current reference signal, the fourth comparator U5 outputs a high level, and the first diode Di is cut off.

[0132] When the second voltage feedback signal is greater than the second reference voltage signal, the sixth comparator U7 outputs a low level, the second diode Dv conducts, and the logic OR circuit 43 enables the voltage control loop 41. When the second voltage feedback signal is less than the second reference voltage signal, the sixth comparator U7 outputs a high level, and the second diode Dv is cut off.

[0133] As can be seen from the above, when the fourth comparator U5 outputs a low level and the sixth comparator U7 outputs a high level, that is, the current error signal is at a low level and the second voltage error signal is at a high level, Di conducts and Dv is cut off, and the logic OR circuit 43 enables the current control loop 42; when the fourth comparator U5 outputs a high level and the sixth comparator U7 outputs a low level, that is, the current error signal is at a high level and the second voltage error signal is at a low level, Di is cut off and Dv conducts, and the logic OR circuit 43 enables the voltage control loop 41. That is, the logic OR circuit 43 can automatically enable one of the current control loop 42 and the voltage control loop 41 according to the magnitudes of the current error signal and the second voltage error signal.

[0134] In the embodiment of the present application, the logic OR circuit formed by the first diode Di and the second diode Dv can have a simple structure and low cost.

[0135] In a possible implementation manner, the above-mentioned PFC main converter includes one of a flyback converter, a boost converter, a buck converter, a buck-boost converter, a cuk converter, and a forward converter.

[0136] Please refer to Figure 4 , the PFC main converter 10 includes a power conversion unit 11, a rectifier diode D5, a rectifier diode Db, a voltage conversion unit 12, and a main power switch Q1. These units can form isolated or non-isolated types of PFC main converters 10 such as a buck converter, a boost converter, and a buck-boost converter. The main power switch Q1 also has a body diode D Q1 . The input end of the PFC main converter 10 includes port 1 and port 2, the main output end includes port 3 and port 4, and the DC output end includes port 5 and port 6.

[0137] The power conversion unit 11 may include an LC filter circuit, a diode full-bridge rectifier circuit, and a filter capacitor Cin. The LC filter circuit includes a capacitor Cf and an inductor Lf. The diode full-bridge rectifier circuit includes diodes D1, D2, D3, and D4.

[0138] One end of the inductor Lf is connected to port 1 of the input end of the PFC main converter 10, the other pole of the inductor Lf is connected to one end of the capacitor Cf, the other end of the capacitor Cf is connected to port 2 of the input end of the PFC main converter 10, and both ends of the capacitor Cf form the output end of the LC filter circuit. The negative electrode of D1 is connected to the negative electrode of D2, the positive electrode of D2 is connected to the negative electrode of D4, the positive electrode of D4 is connected to the positive electrode of D3, and the negative electrode of D3 is connected to the positive electrode of D1; one pole of the output end of the LC filter circuit is connected between the positive electrode of D1 and the negative electrode of D3, and the other pole of the output end of the LC filter circuit is connected between the positive electrode of D2 and the negative electrode of D4. One end of the filter capacitor Cin is connected between the negative electrodes of D1 and D2, and the other end of the filter capacitor Cin is connected between the positive electrodes of D3 and D4. Both ends of the filter voltage Cin form the output end of the power conversion unit 11.

[0139] Please refer to Figure 4 , the circuit composition of the PFC main converter 10 of the flyback converter type is described in detail below:

[0140] The voltage conversion unit 12 includes a dual-winding transformer T1. One end of the primary side of the main winding 121 of T1 is connected to one end of the main power switch Q1, the other end of the primary side of the main winding 121 of T1 is connected to one end of the output end of the power conversion unit 11, and the other end of the main power switch Q1 is connected to the other end of the output end of the power conversion unit 11. One end of the secondary side of the main winding 121 of T1 is connected to one end of the diode D5, the other end of D5 is connected to port 3, and the other end of the secondary side of the main winding 121 of T1 is connected to port 4. One end of the secondary side of the auxiliary winding 122 of T1 is connected to one end of the diode Db, the other end of Db is connected to port 5, and the other end of the secondary side of the auxiliary winding 122 of T1 is connected to port 6.

[0141] Please refer to Figure 5 , the composition of the PFC main converter 10 of the buck converter type is described in detail below:

[0142] The voltage conversion unit 12 includes a dual-winding inductor L1, and the inductor L1 includes a main winding 121 and an auxiliary winding 122. One end of the main power switch Q1 is connected to a port at one end of the output of the power conversion unit 11, the other end of the main power switch Q1 is connected to one end of the main winding 121 of L1, the control end of the main power switch Q1 is connected to the output end of the PFC controller 30, and the other end of the main winding 121 of L1 is connected to port 3 of the main output. One end of the rectifier diode D5 is connected between one end of the power switch and one end of the main winding 121, the other end of D5 is connected to another port of the output of the power conversion unit 11 and is connected to port 4 of the main output. The rectifier diode Db is connected between one end of the auxiliary winding 122 and port 5 of the DC output, and the other end of the auxiliary winding 122 is connected to port 6 of the DC output.

[0143] Please refer to Figure 6 , and the composition of the PFC main converter 10 of the boost converter type is described in detail below:

[0144] The voltage conversion unit 12 includes a dual-winding inductor L1, and the inductor L1 includes a main winding 121 and an auxiliary winding 122. One end of the main winding 121 is connected to a port at one end of the output of the power conversion unit 11, the other end of the main winding 121 is connected to one end of the main power switch Q1, the other end of the main power switch Q1 is connected to another port of the output of the power conversion unit 11, and the other end of the main power switch Q1 is also connected to port 4 of the main output; one end of the rectifier diode D5 is connected between the other end of the main winding 121 and one end of the main power switch Q1, and the other end of D5 is connected to port 3 of the main output. The rectifier diode Db is connected between one end of the auxiliary winding 122 and port 5 of the DC output, and the other end of the auxiliary winding 122 is connected to port 6 of the DC output.

[0145] Please refer to Figure 7 , and the composition of the PFC main converter 10 of the buck-boost converter type is described in detail below:

[0146] The voltage conversion unit 12 includes a dual-winding inductor L1, and the dual-winding inductor L1 includes a main winding 121 and an auxiliary winding 122. One end of the main power switch Q1 is connected to a port at one end of the output of the power conversion unit 11, and the other end of the main power switch Q1 is connected to port 4 of the main output. One end of the main winding 121 is connected between the other end of the main power switch Q1 and port 4, the other end of the main winding 121 is connected to another port of the output of the power conversion unit 11, one end of the rectifier diode D5 is connected between the other end of the main winding 121 and another port of the output of the power conversion unit 11, and the other end of D5 is connected to port 3 of the main output. The rectifier diode Db is connected between one end of the auxiliary winding 122 and port 5 of the DC output, and the other end of the auxiliary winding 122 is connected to port 6 of the DC output.

[0147] In a possible implementation manner, the above-mentioned DC / DC auxiliary converter 20 includes one of a flyback converter, a boost converter, a buck converter, a buck-boost converter, a cuk converter, a forward converter, a bridge converter, a push-pull converter, a single-ended primary inductor converter, and an LLC resonant converter.

[0148] The DC / DC auxiliary converter 20 includes an auxiliary power switch tube Q2, an inductor L2 (or a transformer T2), and a rectifier diode D7. The auxiliary power switch tube Q2, the inductor L2, and the rectifier diode D7 can form isolated or non-isolated types of DC / DC auxiliary converters 20 such as a buck converter, a boost converter, and a buck-boost converter. The auxiliary power switch tube Q2 also has a body diode D Q2 . The auxiliary output terminals of the DC / DC auxiliary converter 20 include port 7 and port 8, and the auxiliary input terminal of the DC / DC auxiliary converter 20 is connected to ports 5 and 6 of the DC output terminal.

[0149] Please refer to Figure 4 , and the composition of the DC / DC auxiliary converter 20 of the buck converter type is described in detail below:

[0150] The DC / DC auxiliary converter 20 includes an auxiliary power switch tube Q2, an inductor L2, and a rectifier diode D7. One end of the auxiliary power switch tube Q2 is connected to port 5 of the DC output terminal, the other end of the auxiliary power switch tube Q2 is connected to one end of the inductor L2, and the other end of the inductor L2 is connected to port 7 of the auxiliary output terminal. One end of the rectifier diode D7 is connected between the other end of the auxiliary power switch tube Q2 and one end of the inductor L2, and the other end of the rectifier diode D7 is simultaneously connected to port 6 of the DC output terminal and port 8 of the auxiliary output terminal.

[0151] Please refer to Figure 8 , and the composition of the DC / DC auxiliary converter 20 of the boost converter type is described in detail below:

[0152] The DC / DC auxiliary converter 20 includes an auxiliary power switch tube Q2, an inductor L2, and a rectifier diode D7. One end of the inductor L2 is connected to port 5 of the DC output terminal, and the other end is connected to one end of the rectifier diode D7. The other end of the rectifier diode D7 is connected to port 7 of the auxiliary output terminal. One end of the auxiliary power switch tube Q2 is connected between port 6 of the DC output terminal and port 8 of the auxiliary output terminal, and the other end is connected between the other end of the inductor L2 and one end of the rectifier diode D7.

[0153] Please refer to Figure 9 , and the composition of the DC / DC auxiliary converter 20 of the buck-boost converter type is described in detail below:

[0154] The DC / DC secondary converter 20 includes a secondary power switch tube Q2, an inductor L2, and a rectifier diode D7. One end of the secondary power switch tube Q2 is connected to port 5 of the DC output terminal, and the other end is connected to port 8 of the secondary output terminal. The rectifier diode D7 is connected between port 6 of the DC output terminal and port 7 of the secondary output terminal. One end of the inductor L2 is connected between the other end of the secondary power switch tube Q2 and port 8 of the secondary output terminal, and the other end of the inductor L2 is connected between port 6 and the rectifier diode D7.

[0155] Please refer to Figure 10 , and the composition of the DC / DC secondary converter 20 of the negative voltage step-down converter type is described in detail below:

[0156] The DC / DC secondary converter 20 includes a secondary power switch tube Q2, an inductor L2, and a rectifier diode D7. One end of the secondary power switch tube Q2 is connected to one end of the inductor L2, and the other end is connected to port 5 of the DC output terminal. The other end of the inductor L2 is connected to port 7 of the secondary output terminal. One end of the rectifier diode D7 is connected between port 6 of the DC output terminal and port 8 of the secondary output terminal, and the other end is connected between one end of the secondary power switch tube Q2 and one end of the inductor L2.

[0157] Please refer to Figure 11 , and the composition of the DC / DC secondary converter 20 of the flyback converter type is described in detail below:

[0158] The DC / DC secondary converter 20 includes a secondary power switch tube Q2, a transformer T2, and a rectifier diode D7. Among them, the transformer T2 includes a first winding and a second winding. One end of the first winding is connected to port 5 of the DC output terminal, and the other end is connected to one end of the secondary power switch tube Q2; the other end of the secondary power switch tube Q2 is connected to port 6 of the DC output terminal; one end of the second winding of the transformer T2 is connected to one end of the rectifier diode D7, the other end of the rectifier diode D7 is connected to port 7 of the secondary output terminal, and the other end of the second winding is connected to port 8 of the secondary output terminal.

[0159] In addition, filter capacitors Co1, Cb, and Co2 are also provided in the circuit. Among them, the filter capacitor Co1 is connected between port 3 and port 4 of the main output terminal to filter the main output voltage Vo1 output from the main output terminal. The filter capacitor Cb is connected between port 5 and port 6 of the DC output terminal to filter the DC output voltage output from the DC output terminal. The filter capacitor Co2 is connected between port 7 and port 8 of the secondary output terminal to filter the secondary output voltage Vo2 output from the secondary output terminal.

[0160] In a possible implementation manner, the voltage stress of the above-mentioned DC / DC secondary converter 20 is less than the first threshold, and the current stress of the above-mentioned DC / DC secondary converter 20 is less than the second threshold.

[0161] Specifically, the main output voltage Vo1 is greater than the auxiliary output voltage Vo2. The PFC main converter 10 provides most of the output power for the battery 60, and the DC / DC auxiliary converter 20 provides a small part of the output power for the battery 60. Therefore, the voltage stress and current stress of the power devices in the DC / DC auxiliary converter 20 are small, thereby reducing the component cost.

[0162] In a possible implementation manner, the above-mentioned PFC controller 30 further includes a first communication unit, the above-mentioned DC / DC controller 40 further includes a second communication unit, and the first communication unit establishes a communication connection with the second communication unit.

[0163] In the embodiment of the present application, there is a communication connection between the PFC controller 30 and the DC / DC controller 40. The PFC controller 30 and the DC / DC controller 40 coordinate their respective controls and operations based on this communication connection. The PFC controller 30 and the DC / DC controller 40 can send real-time instructions and operating parameters to each other, set the control mode and adjust the working state, so that the PFC main converter 10 and the DC / DC auxiliary converter 20 operate optimally, which can further improve the performance and reliability of the AC / DC charger.

[0164] Optionally, in a possible implementation manner, the PFC controller 30 and the DC / DC controller 40 can be integrated into one, two or more analog chips, or one, two or more digital chips such as MCUs and DSPs that require embedded software programming can be used. Their working principles are the same as those of the PFC controller 30 and the DC / DC controller 40 in the above embodiment, and will not be repeated here.

[0165] It should be understood that the application of the present application is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above description. All such improvements and transformations should fall within the protection scope of the appended claims of the present application.

Claims

1. An AC / DC charger, characterized in that, it includes: a power factor correction (PFC) main converter, a DC / DC auxiliary converter, a PFC controller, and a DC / DC controller; the PFC main converter includes a main output terminal and a DC output terminal, the DC output terminal is connected to the auxiliary input terminal of the DC / DC auxiliary converter, and the main output terminal is connected in series with the auxiliary output terminal of the DC / DC auxiliary converter to form a total output terminal; the control terminal of the PFC controller is connected to the PFC main converter, and the DC / DC controller includes a voltage control loop and a current control loop; the output terminals of the voltage control loop and the current control loop are respectively connected to the control terminal of the DC / DC controller, and the control terminal of the DC / DC controller is connected to the DC / DC auxiliary converter; the PFC main converter outputs a main output voltage through the main output terminal; the PFC main converter transmits the output DC output voltage to the auxiliary input terminal of the DC / DC auxiliary converter through the DC output terminal; the DC / DC auxiliary converter processes the DC output voltage to obtain an auxiliary output voltage, and the ripple of the auxiliary output voltage is opposite in phase to the ripple of the main output voltage, and the auxiliary output voltage is output through the auxiliary output terminal; after receiving the main output voltage and the auxiliary output voltage, the total output terminal forms a total output voltage and an output total current; the PFC controller samples a first feedback voltage and uses the first feedback voltage to control the input voltage and input current frequency of the PFC main converter to be the same and in phase; the voltage control loop samples a second feedback voltage and uses the second feedback voltage to control the ripple of the auxiliary output voltage output from the auxiliary output terminal of the DC / DC auxiliary converter to be opposite in phase to the ripple of the main output voltage; the current control loop samples the total current and uses the total current to control the output current of the DC / DC auxiliary converter to make the total current constant; the total output terminal is connected to a storage battery, and the total output voltage is used to charge the storage battery; the first feedback voltage includes one of the main output voltage and the auxiliary output voltage, and the second feedback voltage includes the total output voltage.

2. The AC / DC charger according to claim 1, characterized in that, the PFC main converter further includes a power conversion unit, a main power switch tube, and a voltage conversion unit, the main power switch tube is connected between the output terminal of the power conversion unit and the input terminal of the voltage conversion unit, the control terminal of the main power switch tube is connected to the control terminal of the PFC controller, and the output terminal of the voltage conversion unit is connected to the main output terminal and the DC output terminal; the PFC controller controls the conduction and cutoff of the main power switch tube; when the main power switch tube is conducting, the power conversion unit provides electrical energy for the voltage conversion unit, and the voltage conversion unit stores electrical energy; when the main power switch tube is cutoff, the power conversion unit stops providing electrical energy for the voltage conversion unit, and the voltage conversion unit releases electrical energy.

3. The AC / DC charger according to claim 2, wherein, the voltage conversion unit includes a main winding and an auxiliary winding; one end of the main winding is connected to one end of the main power switch tube, and the other end of the main winding is connected to the main output terminal; one end of the auxiliary winding is connected to one end of the main power switch tube, and the other end of the auxiliary winding is connected to the auxiliary input terminal; the voltage conversion unit outputs the main output voltage to the main output terminal through the main winding; the voltage conversion unit outputs the DC output voltage to the DC output terminal through the auxiliary winding.

4. The AC / DC charger according to claim 3, wherein, the PFC controller includes a sampling unit and an adjustment feedback unit; the output terminal of the sampling unit is connected to the input terminal of the adjustment feedback unit, and the output terminal of the adjustment feedback unit is connected to the control terminal of the main power switch tube; the sampling unit is configured to: sample the first feedback voltage; the adjustment feedback unit is configured to: generate a first switch tube drive signal based on the first feedback voltage; the first switch tube drive signal is used to control the main power switch tube.

5. The AC / DC charger according to claim 4, wherein, the sampling unit includes a first sampling terminal, a second sampling terminal, and a third sampling terminal; the adjustment feedback unit includes: a first comparator, a second comparator, a third comparator, a first reference voltage source, a first sawtooth wave signal source, and a trigger; the output terminal of the first reference voltage source is connected to the positive input terminal of the first comparator, and the first sampling terminal is connected to the negative input terminal of the first comparator; the output terminal of the first comparator is connected to the positive input terminal of the second comparator, and the negative input terminal of the second comparator is connected to the second sampling terminal; the output terminal of the second comparator is connected to the positive input terminal of the third comparator, the first sawtooth wave signal source is connected to the negative input terminal of the third comparator, the output terminal of the third comparator is connected to the first input terminal of the trigger, the third sampling terminal is connected to the second input terminal of the trigger, and the output terminal of the trigger is connected to the control terminal of the PFC controller; the first comparator receives the first feedback voltage from the first sampling terminal and the first reference voltage signal from the first reference voltage source, compares the first feedback voltage with the first reference voltage signal, and forms a first voltage error signal; the second comparator receives the switch tube voltage signal from the second sampling terminal and the first voltage error signal from the first comparator, compares the first voltage error signal with the switch tube voltage signal, and obtains the current control signal of the main power switch tube, and the switch tube voltage signal is obtained by converting the current signal of the main power switch tube. The third comparator receives the current control signal from the second comparator and the first sawtooth signal from the first sawtooth signal source, compares the control signal with the sawtooth signal, and obtains a stop pulse signal; the third sampling terminal samples the electric energy of the voltage conversion unit to form a start pulse signal; The flip-flop receives the stop pulse signal and the start pulse signal, and generates the first switch tube drive signal based on the start pulse signal and the stop pulse signal, and the first switch tube drive signal is used to control the conduction and disconnection of the main power switch tube.

6. The AC / DC charger according to claim 1, characterized in that the DC / DC auxiliary converter includes an auxiliary power switch tube, an inductor and a rectifier diode; one end of the auxiliary power switch tube is connected to one pole of the auxiliary input terminal of the DC / DC auxiliary converter, the other end of the auxiliary power switch tube is connected to one end of the inductor, the other end of the inductor is connected to one pole of the auxiliary output terminal, and one end of the rectifier diode is connected between the other end of the auxiliary power switch tube and one end of the inductor, and the other end of the rectifier diode is connected between the other pole of the auxiliary input terminal of the DC / DC auxiliary converter and the other pole of the auxiliary output terminal; when the auxiliary power switch tube is conducting, the rectifier diode is cut off, the auxiliary input terminal of the DC / DC auxiliary converter receives the DC output voltage, provides electric energy for the inductor, and the inductor stores electric energy; when the auxiliary power switch tube is cut off, the rectifier diode is conducting, the inductor, the rectifier diode and the auxiliary output terminal form a current loop, the inductor releases electric energy, provides electric energy for the auxiliary output terminal, and enables the auxiliary output terminal to output the auxiliary output voltage.

7. The AC / DC charger according to claim 6, characterized in that the DC / DC controller includes a fourth comparator, a fifth comparator, a sixth comparator, a current reference source, a second reference voltage source, a second sawtooth signal source, a current sampling terminal, a voltage sampling terminal and a logic OR circuit, the fourth comparator, the fifth comparator, the current reference source and the current sampling terminal constitute the current control loop, and the sixth comparator, the fifth comparator, the second reference voltage source and the voltage sampling terminal constitute the voltage control loop; The positive input terminal of the fourth comparator is connected to the output terminal of the current reference source, the negative input terminal of the fourth comparator is connected to the current sampling terminal, and the output terminal of the fourth comparator is connected to the first input terminal of the logic OR circuit; the positive input terminal of the sixth comparator is connected to the output terminal of the second reference voltage source, the negative input terminal of the sixth comparator is connected to the voltage sampling terminal, and the output terminal of the sixth comparator is connected to the second input terminal of the logic OR circuit; the output terminal of the logic OR circuit is connected to the positive input terminal of the fifth comparator, the negative input terminal of the fifth comparator is connected to the output terminal of the second sawtooth signal source, and the output terminal of the fifth comparator is connected to the control terminal of the DC / DC controller; The fourth comparator receives a current feedback signal from the current sampling terminal and a current reference signal from the current reference source. After comparing the current reference signal with the current feedback signal, a current error signal is formed; The sixth comparator receives a second feedback voltage from the voltage sampling terminal and a second reference voltage signal from the second reference voltage source. After comparing the second feedback voltage with the second reference voltage signal, a second voltage error signal is formed; The fifth comparator receives the current error signal or the second voltage error signal and a second sawtooth signal from the sawtooth signal source. After comparing the second sawtooth signal with the current error signal or the second voltage error signal, a second switch tube drive signal is formed, and the second switch tube drive signal is used to control the conduction and disconnection of the auxiliary power switch tube.

8. The AC / DC charger according to claim 7, wherein, the logic OR circuit includes a first diode and a second diode; the anode of the first diode is connected to the output terminal of the logic OR circuit, and the cathode of the first diode is connected to the first input terminal of the logic OR circuit; the anode of the second diode is connected between the anode of the first diode and the output terminal of the logic OR circuit, and the cathode of the second diode is connected to the second input terminal of the logic OR circuit.

9. The AC / DC charger according to claim 1, wherein, the voltage stress of the DC / DC auxiliary converter is less than a first threshold, and the current stress of the DC / DC auxiliary converter is less than a second threshold.

10. The AC / DC charger according to claim 1, wherein, the PFC controller includes a first communication unit, the DC / DC controller includes a second communication unit, and the first communication unit establishes a communication connection with the second communication unit.

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