Power supply

Abstract

The present disclosure is a power supply, comprising: a power factor correction circuit for converting a DC link voltage into a first voltage; the LLC converter comprises a primary side circuit and a secondary side circuit which are coupled with each other, the primary side circuit receives the first voltage, and the secondary side circuit outputs a second voltage according to the first voltage; the auxiliary conversion circuit is used for converting the first voltage into an auxiliary voltage; the secondary side controller is arranged on the secondary side of the LLC converter and is used for controlling the operation of the LLC converter; and the voltage tracking circuit is used for detecting the auxiliary voltage and outputting a detection signal corresponding to a detection result to the secondary side controller, so that the secondary side circuit establishes a reverse waveform opposite to the waveform of the direct current chain voltage in real time according to the ripple change of the direct current chain voltage and controls the operation of the LLC converter according to the reverse waveform.

Description

Technical Field

[0001] The present invention relates to a power supply, and more particularly to a power supply capable of performing ripple compensation. Background Art

[0002] Power supplies are a very common electronic product in daily life. Almost all electrical devices are equipped with power supplies to supply power to the internal components or electronic elements of the electrical devices. Power supplies usually include a power factor correction (PFC) circuit and an LLC resonant converter. The power factor correction circuit receives an AC voltage, such as a mains supply, and performs power factor correction on the AC voltage to output a transitional DC voltage. The LLC resonant converter receives the transitional DC voltage and converts the received transitional DC voltage into an output DC voltage of different voltage levels in a resonant manner.

[0003] However, in the existing power supply with LLC resonant converter, along with the access of the power grid through the uncontrolled rectifier bridge, there will be a 2x output frequency ripple problem, the frequency of which is about 100Hz, which affects the safe and stable operation of the power supply and even causes the power supply to malfunction.

[0004] Although some power supplies currently use isolators, such as optical coupling elements, to send the input voltage at the zero crossing point to the controller on the secondary side of the power supply, so that the controller on the secondary side can reconstruct the waveform and make corresponding adjustments to the reference voltage used to adjust the output voltage to offset the ripple. However, different input voltage frequencies, different load operating temperature conditions, etc. will cause the capacitance value to change, and thus cause different ripple changes. Therefore, this approach cannot take into account all aspects, but can only adjust to a certain extent.

[0005] Some power supplies use controllers to detect the output voltage ripple and separate it to generate a reverse waveform to control the output voltage ripple. However, the method of detecting the output voltage ripple can only control the ripple within a certain range, not for the source, and must be combined with current feedback. Moreover, in order to facilitate the detection of bulk voltage, the controller must be located on the primary side. In addition, the method of detecting the output voltage ripple on the secondary side of the power supply can only control the constant resistance load, and cannot handle the constant current load.

[0006] Therefore, how to develop a power supply that overcomes the above-mentioned deficiencies is currently the most urgent issue to be solved. Summary of the invention

[0007] The purpose of the present disclosure is to provide a power supply, which uses a voltage tracking circuit to detect the auxiliary voltage of an auxiliary conversion circuit, so that a secondary side controller located on the secondary side of an LLC converter can reconstruct a real-time reverse waveform to control the operation of the LLC converter according to the ripple change of the DC link voltage, thereby allowing the ripple adjustment method to be tailored to the source size of the ripple, and regardless of the input capacitor size, input frequency change or load change, the controller can provide the best ripple compensation value.

[0008] To achieve the aforementioned purpose, a preferred embodiment of the present disclosure provides a power supply, comprising: a power factor correction circuit for converting a DC link voltage into a first voltage; an LLC converter, comprising a primary side circuit and a secondary side circuit coupled to each other, the primary side circuit being electrically connected to the power factor correction circuit to receive the first voltage, and the secondary side circuit outputting a second voltage based on the first voltage; an auxiliary conversion circuit being electrically connected to the power factor correction circuit to convert the first voltage into an auxiliary voltage; a secondary side controller being arranged on the secondary side of the LLC converter to control the operation of the LLC converter; and a voltage tracking circuit being electrically connected to the auxiliary conversion circuit to detect the auxiliary voltage, and outputting a detection signal to the secondary side controller corresponding to the detection result, so that the secondary side circuit establishes a reverse waveform that is reverse to the waveform of the DC link voltage in real time based on the ripple change of the DC link voltage, and controls the operation of the LLC converter based on the reverse waveform to suppress the secondary side voltage ripple generated by the DC link voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A system block diagram of a power supply according to a preferred embodiment of the present disclosure;

[0010] Figure 2 for Figure 1 A partial detailed circuit diagram of the power supply shown; and

[0011] Figure 3 for Figure 1 FIG. 1 is a schematic diagram showing waveforms of a DC link voltage received by a power supply and a detection signal on a first end of a third capacitor of the power supply.

[0012] Description of reference numerals:

[0013] 1: Power supply

[0014] 2: Power factor correction circuit

[0015] 3: LLC Converter

[0016] 4: Auxiliary conversion circuit

[0017] 5: Secondary side controller

[0018] 6: Voltage tracking circuit

[0019] Vin: DC link voltage

[0020] 30: Primary side circuit

[0021] 31: Secondary side circuit

[0022] T: Transformer

[0023] D1: The first diode

[0024] C1: First capacitor

[0025] R1: First resistor

[0026] D2: Second diode

[0027] R2: Second resistor

[0028] S: Auxiliary switch

[0029] C2: Second capacitor

[0030] P1: Primary winding

[0031] S1: First secondary winding

[0032] S2: Second secondary winding

[0033] G: Ground terminal

[0034] R3: The third resistor

[0035] D3: The third diode

[0036] C3: The third capacitor

[0037] R4: The fourth resistor

[0038] R5: The fifth resistor

[0039] R6: The sixth resistor

[0040] C4: The fourth capacitor

[0041] L: Inductance

[0042] 7: Primary side controller

[0043] 40: Auxiliary controller DETAILED DESCRIPTION

[0044] Some typical embodiments that embody the features and advantages of the present disclosure will be described in detail in the following description. It should be understood that the present disclosure can have various changes in different implementations without departing from the scope of the present disclosure, and the descriptions and illustrations therein are essentially used for illustrative purposes rather than for limiting the present disclosure.

[0045] See also Figure 1 , Figure 2 and Figure 3 ,in Figure 1 is a system block diagram of a power supply according to a preferred embodiment of the present disclosure, Figure 2 for Figure 1 The power supply circuit diagram shown is a partial detail diagram. Figure 3 for Figure 1 The DC link voltage received by the power supply shown in the figure and the waveform diagram of the detection signal on the first end of the third capacitor of the power supply. In the present disclosure, the power supply 1 of the present disclosure includes a power factor correction circuit 2, an LLC converter 3, an auxiliary conversion circuit 4, a secondary side controller 5 and a voltage tracking circuit 6.

[0046] The input end of the power factor correction circuit 2 can receive the DC link voltage. The power factor correction circuit 2 is used to perform power factor correction on the DC link voltage to convert it into a first voltage and output the first voltage at the output end of the power factor correction circuit 2.

[0047] The input end of the LLC converter 3 is electrically connected to the output end of the power factor correction circuit 2, the output end of the LLC converter 3 is electrically connected to the load (not shown), and the LLC converter 3 includes a primary side circuit 30 and a secondary side circuit 31 coupled to each other, wherein the primary side circuit 30 is electrically connected to the input end of the LLC converter 3, and receives a first voltage through the input end of the LLC converter 3, and the secondary side circuit 31 is electrically connected to the output end of the LLC converter 3, and outputs a second voltage at the output end of the LLC converter 3 according to the first voltage. In some embodiments, the primary side circuit 30 and the secondary side circuit 31 can be coupled to each other through a transformer (not shown), and the primary side circuit 30 is disposed on the primary side of the LLC converter 3, and the secondary side circuit 31 is disposed on the secondary side of the LLC converter 3.

[0048] The input end of the auxiliary conversion circuit 4 is electrically connected to the output end of the power factor correction circuit 2. The auxiliary conversion circuit 4 is used to convert the first voltage into an auxiliary voltage, such as 12V, and output it at the output end of the auxiliary conversion circuit 4 to provide it to some components of the power supply 1, such as a fan and / or a controller, for use.

[0049] The secondary side controller 5 is disposed on the secondary side of the LLC converter 3 in the same manner as the secondary side circuit 31, and is used to control the operation of the LLC converter 3. The voltage tracking circuit 6 is electrically connected to the output end of the auxiliary conversion circuit 4, and is used to detect the auxiliary voltage output by the auxiliary conversion circuit 4, and output a detection signal to the secondary side controller 5 corresponding to the detection result, so that the secondary side controller 5 tracks the ripple change of the DC link voltage according to the detection signal, and then establishes a reverse waveform (such as the reverse waveform of the DC link voltage) in real time. Figure 3As shown in FIG. 1 , the operation of LLC converter 3 is controlled according to the reverse waveform to suppress the secondary side voltage ripple generated by the DC link voltage. In the present disclosure, the technology of controlling the operation of LLC converter 3 according to the ripple change of the DC link voltage to suppress the voltage ripple is not the focus of the present disclosure, and the technology is commonly used in power supplies, so it will not be repeated here.

[0050] As can be seen from the above, the power supply 1 of the present invention detects the auxiliary voltage output by the auxiliary conversion circuit 4 through the voltage tracking circuit 6, and provides the detection result to the secondary side controller 5 located on the secondary side of the LLC converter 3, so that the secondary side controller 5 can establish a reverse waveform that is opposite to the waveform of the DC link voltage in real time according to the ripple change of the DC link voltage, and then control the operation of the LLC converter 3 according to the reverse waveform to suppress the voltage ripple of the DC link voltage. In this way, the power supply 1 of the present invention can directly tailor the corresponding ripple compensation method according to the size of the ripple source (i.e., the DC link voltage), so that regardless of the input capacitor size, input frequency change or load change, the secondary side controller 5 can provide the best ripple compensation value. In addition, since the secondary side controller 5 of the power supply 1 of the present invention establishes a reverse waveform that is opposite to the waveform of the DC link voltage in real time according to the ripple change of the DC link voltage, and then performs ripple compensation, instead of performing ripple compensation based on the output voltage (i.e., the second voltage) of the power supply 1, the power supply 1 of the present invention can perform ripple compensation for constant resistance loads and constant current loads.

[0051] In some embodiments, the auxiliary conversion circuit 4 includes a transformer T, a first diode D1, a first capacitor C1, a first resistor R1, a second diode D2, a second resistor R2, an auxiliary switch S and a second capacitor C2. The transformer T includes a primary winding P1, a first secondary winding S1 and a second secondary winding S2, wherein the first end (the same name end) and the second end of the primary winding P1 are respectively electrically connected to the output end of the power factor correction circuit 2, and the primary winding P1 is reversely coupled to the first secondary winding S1 and the second secondary winding S2. The first end of the auxiliary switch S is electrically connected to the second end of the primary winding P1, and the second end of the auxiliary switch S is electrically connected to the ground end G. The first end of the second capacitor C2 is electrically connected to the first end of the auxiliary switch S, and the second end of the second capacitor C2 is electrically connected to the second end of the auxiliary switch S. The first end (the same name end) of the first secondary winding S1 is electrically connected to the ground end G, the second end of the first secondary winding S1 is electrically connected to the voltage tracking circuit 6, and outputs the auxiliary voltage, and the anode end of the first diode D1 is electrically connected to the second end of the first secondary winding S1. The first end of the first capacitor C1 is electrically connected to the cathode end of the first diode D1, and the second end of the first capacitor C1 is electrically connected to the ground end G. The first resistor R1 is connected in parallel with the first capacitor C1. The first end (the same name end) of the second secondary winding S2 is electrically connected to the ground end G. The anode end of the second diode D2 is electrically connected to the second end of the second secondary winding S2. The first end of the second resistor R2 is electrically connected to the cathode end of the second diode D2, and the second end of the second resistor R2 outputs the auxiliary voltage.

[0052] In some embodiments, the voltage tracking circuit 6 includes a third resistor R3, a third diode D3, a third capacitor C3, a fourth resistor R4, a fifth resistor R5 and a sixth resistor R6. The first end of the third resistor R3 is electrically connected to the second end of the first secondary winding S1. The cathode end of the third diode D3 is electrically connected to the second end of the third resistor R3. The first end of the third capacitor C3 is electrically connected to the anode end of the third diode D3, and the first end of the third capacitor C3 is electrically connected to the secondary side controller 5, the first end of the third capacitor C3 outputs a detection signal to the secondary side controller 5, and the second end of the third capacitor C3 is electrically connected to the ground terminal G. The first end of the fourth resistor R4 is electrically connected to the anode end of the third diode D3. The first end of the fifth resistor R5 is electrically connected to the second end of the fourth resistor R4, and the second end of the fifth resistor R5 is electrically connected to the ground terminal G. The first end of the sixth resistor R6 is electrically connected to the second end of the fourth resistor R4, and the second end of the sixth resistor R6 is electrically connected to the voltage source VS. By Figure 2 It can be seen that the voltage of the detection signal at the first end of the third capacitor C3 is as follows:

[0053]

[0054] Wherein Vc1 is the voltage of the detection signal on the first end of the third capacitor C3, Np is the number of turns of the primary winding P1, Ns1 is the number of turns of the first secondary winding S1, and Vin is the DC link voltage. It can be seen that the voltage waveform of the detection signal is the reverse of the voltage waveform of the DC link voltage, and the voltage of the detection signal is proportional to the voltage of the DC link voltage.

[0055] In some embodiments, the auxiliary conversion circuit 4 further includes a fourth capacitor C4 and an inductor L, wherein a first end of the fourth capacitor C4 is electrically connected to a first end of the primary winding P1, and a second end of the fourth capacitor C4 is electrically connected to a ground end. The inductor L is electrically connected between the first end and the second end of the primary winding P1.

[0056] The detection signal output by the voltage tracking circuit 6 can not only be used for ripple compensation, but also in some embodiments, when the mains voltage has a transient change, the DC link voltage will have a corresponding drastic change. The detection signal output by the voltage tracking circuit 6 can warn the secondary side controller 5 in advance, so that the secondary side controller 5 can control the operation of the LLC converter 3 accordingly. Therefore, the second voltage output by the secondary side circuit 31 will not rise or fall with the transient change of the DC link voltage, so as to achieve the protection function. In this way, the stability of the power supply 1 is good. In addition, the voltage tracking circuit 6 can be used to set different shutdown voltages for the capacitance decay of different input capacitors and different load conditions. To further explain, because the load condition is reflected on the secondary side of the LLC converter 3, and the BULK voltage information is on the primary side of the LLC converter 3, the detection signal output by the voltage tracking circuit 6 reflects the BULK voltage to the secondary side of the LLC converter 3, so as to shut down according to the capacitance decay of different input capacitors, different load conditions and the detected BULK voltage, so as to achieve the effect of extending the dynamic enhancement time of the power supply 1. In some embodiments, the power supply 1 further includes a primary side controller 7, which is disposed on the primary side of the LLC converter 3 and is electrically connected to the power factor correction circuit 2 to control the operation of the power factor correction circuit 2. In addition, the primary side controller 7 can also detect the first voltage output by the power factor correction circuit 2 and adjust the magnitude of the first voltage output by the power factor correction circuit 2 accordingly. In other embodiments, the power supply 1 further includes an auxiliary controller 40, which is electrically connected to the auxiliary conversion circuit 4, for example, electrically connected to the control end of the auxiliary switch S, to control the operation of the auxiliary conversion circuit 4, for example, to control the operation of the auxiliary switch S.

[0057] In summary, the present disclosure provides a power supply, which detects the auxiliary voltage output by the auxiliary conversion circuit through a voltage tracking circuit, and provides the detection result to the secondary side controller located on the secondary side of the LLC converter, so that the secondary side controller establishes a reverse waveform that is opposite to the waveform of the DC link voltage in real time according to the ripple change of the DC link voltage, and then controls the operation of the LLC converter according to the reverse waveform to suppress the voltage ripple of the DC link voltage. In this way, the power supply of the present disclosure can directly tailor the corresponding ripple compensation method according to the size of the ripple source, so that regardless of the input capacitor size, input frequency change or load change, the secondary side controller can give the best ripple compensation value. In addition, since the secondary side controller of the power supply of the present disclosure establishes a reverse waveform that is opposite to the waveform in real time according to the ripple change of the DC link voltage, and then performs ripple compensation, it does not perform ripple compensation according to the output voltage of the power supply 1, so the power supply of the present disclosure can perform ripple compensation for different load conditions such as constant resistance load and constant current load.

Claims

1. A power supply, comprising: A power factor correction circuit, used for converting a DC link voltage into a first voltage; An LLC converter comprises a primary side circuit and a secondary side circuit coupled to each other, the primary side circuit is electrically connected to the power factor correction circuit to receive the first voltage, and the secondary side circuit outputs a second voltage according to the first voltage; an auxiliary conversion circuit, electrically connected to the power factor correction circuit, for converting the first voltage into an auxiliary voltage; a secondary-side controller, disposed on a secondary side of the LLC converter, for controlling the operation of the LLC converter; and A voltage tracking circuit is electrically connected to the auxiliary conversion circuit, and is used to detect the auxiliary voltage, and output a detection signal to the secondary side controller corresponding to the detection result, so that the secondary side circuit can establish a reverse waveform that is reverse to the waveform of the DC link voltage in real time according to the ripple change of the DC link, and control the operation of the LLC converter according to the reverse waveform to suppress the secondary side voltage ripple generated by the DC link voltage.

2. The power supply as described in claim 1, wherein the auxiliary conversion circuit comprises a transformer, the transformer comprises a primary winding, a first secondary winding and a second secondary winding, wherein a first end and a second end of the primary winding are respectively electrically connected to the power factor correction circuit, and the primary winding is reversely coupled to the first secondary winding and the second secondary winding, respectively, a first end of the first secondary winding is electrically connected to a ground end, a second end of the first secondary winding is electrically connected to the voltage tracking circuit, and outputs the auxiliary voltage.

3. The power supply as claimed in claim 2, wherein the auxiliary conversion circuit comprises a first diode, a first capacitor, a first resistor, a second diode, a second resistor, an auxiliary switch and a second capacitor, wherein a first end of the auxiliary switch is electrically connected to the second end of the primary winding, a second end of the auxiliary switch is electrically connected to the ground, a first end of the second capacitor is electrically connected to the first end of the auxiliary switch, a second end of the second capacitor is electrically connected to the second end of the auxiliary switch, an anode end of the first diode is electrically connected to the second end of the first secondary winding, a first end of the first capacitor is electrically connected to a cathode end of the first diode, a second end of the first capacitor is electrically connected to the ground, the first resistor is connected in parallel with the first capacitor, a first end of the second secondary winding is electrically connected to the ground, an anode end of the second diode is electrically connected to a second end of the second secondary winding, a first end of the second resistor is electrically connected to a cathode end of the second diode, and a second end of the second resistor outputs the auxiliary voltage.

4. The power supply as claimed in claim 2, wherein the voltage tracking circuit comprises a third resistor, a third diode, a third capacitor, a fourth resistor, a fifth resistor and a sixth resistor, a first end of the third resistor is electrically connected to the second end of the first secondary winding, a cathode end of the third diode is electrically connected to a second end of the third resistor, a first end of the third capacitor is electrically connected to an anode end of the third diode, and the first end of the third capacitor is electrically connected to the secondary-side controller and outputs the detection signal to the secondary-side controller, a second end of the third capacitor is electrically connected to the ground end, a first end of the fourth resistor is electrically connected to the anode end of the third diode, a first end of the fifth resistor is electrically connected to a second end of the fourth resistor, a second end of the fifth resistor is electrically connected to the ground end, a first end of the sixth resistor is electrically connected to the second end of the fourth resistor, and a second end of the sixth resistor is electrically connected to a voltage source.

5. The power supply as claimed in claim 2, wherein the auxiliary conversion circuit further comprises a fourth capacitor, a first end of the fourth capacitor is electrically connected to the first end of the primary winding, and a second end of the fourth capacitor is electrically connected to a ground end. 6 . The power supply as claimed in claim 2 , wherein the auxiliary conversion circuit further comprises an inductor electrically connected between the first end and the second end of the primary winding. 7 . The power supply as claimed in claim 2 , further comprising an auxiliary controller electrically connected to the auxiliary conversion circuit for controlling the operation of the auxiliary conversion circuit.

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