Power supply device and control method thereof

Abstract

To provide a power source device for improving the formation quality of an oxide film present on an anode aluminum foil, and a method of controlling the same.SOLUTION: A power unit comprises an output terminal and outputs an output voltage. An electrolytic tank contains an electrolytic solution. An anode is disposed in the electrolytic solution and is connected to the output terminal of the power unit. A cathode is disposed in the electrolytic solution and is connected to the output terminal of the power unit. Metal foil is attached to the anode and is chemically converted according to the output voltage. A control unit is connected to the power unit and controls the output voltage of the power unit to have a constant voltage region, a rising voltage pulse region and a falling voltage pulse region. The bottom value of the falling voltage pulse region satisfies the following relational expression: 0<Umin≤Ufn. Herein, Ufn represents a voltage value in the constant voltage region and Umin represents the bottom value of the falling voltage pulse region.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a power supply device and a control method thereof, and particularly to a power supply device for forming a metal foil and a control method thereof.

Background Art

[0002] An aluminum electrolytic capacitor includes at least a positive electrode, a negative electrode, and an electrolytic solution. A metal foil is a material used to manufacture the positive and negative electrodes of an aluminum electrolytic capacitor and is mainly used for storing electric charges. The metal foil is formed from high-purity aluminum foil as the main raw material through a series of processing steps such as corrosion and formation. To explain the manufacturing process of an aluminum electrolytic capacitor in more detail, after winding an anodic aluminum foil covered with a dielectric layer (i.e., an oxide film) by corrosion, a corroded cathodic aluminum foil, and electrolytic paper, it is immersed in an electrolytic solution and encapsulated in an aluminum case for manufacturing.

[0003] The quality of the metal foil has a decisive influence on the overall performance of the aluminum electrolytic capacitor. The corrosion process and formation process of the metal foil directly determine the performance of the aluminum electrolytic capacitor such as capacitance, leakage current, loss, lifespan, reliability, and volume. For example, the larger the specific volume of the metal foil, the higher the unit charge amount of the metal foil, and the smaller the volume of the aluminum electrolytic capacitor that can be manufactured at the same voltage. Therefore, the metal foil is the part with the highest technical content and added value in the aluminum electrolytic capacitor.

[0004] The formation process involves placing an anodic aluminum foil in an electrolytic solution, applying a high DC voltage to the anodic aluminum foil, and forming an oxide film on the surface of the anodic aluminum foil through an electrolysis reaction and an oxidation reaction. The formation process directly affects the quality of the oxide film, that is, by controlling whether the arrangement of aluminum oxide (γ-Al2O3) in the oxide film is uniform and dense, or whether there are excess impurity ions in the oxide film, the dielectric constant, leakage current, breakdown voltage, etc. of the aluminum electrolytic capacitor are determined, and ultimately the capacitance and lifespan of the aluminum electrolytic capacitor are determined. Therefore, improving the formation process to improve the quality of the oxide film formed on the anodic aluminum foil is the research goal of those skilled in the art.

[0005] Therefore, it is currently an urgent task to develop a power supply device and its control method for improving the quality of formation.

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a power supply device and a control method thereof. By controlling, with a control unit, an output voltage output by a power unit to have a rising voltage pulse region, a falling voltage pulse region, and a constant voltage region, or by controlling an output current output by the power unit to have a rising current pulse region, a falling current pulse region, and a constant current region, a weak portion of the oxide film is broken, the processes of dissolution and destruction are delayed, the metal foil is regenerated to fill the dissolved portion, thereby achieving the effect of improving the quality of the oxide film and further improving the capacitance and lifespan of the aluminum electrolytic capacitor. Also, as can be understood from the relational expression that the valley value of the falling voltage pulse region (or the falling current pulse region) should satisfy, the valley value of the falling voltage pulse region (or the falling current pulse region) needs to be greater than 0, thereby ensuring that the electrode polarity in the electrolytic cell does not reverse and further avoiding corrosion and dissolution of the metal material constituting the cathode. Further, the valley value of the falling voltage pulse region is much lower than the peak value of the rising voltage pulse region, and the valley value of the falling current pulse region is much lower than the peak value of the rising current pulse region, so that a large local voltage and current dip effect is generated to quickly complete the depolarization and dissolution processes of the oxide film, shorten the dynamic repair time, and reduce the energy consumption of the entire power supply device.

Means for Solving the Problems

[0007] To achieve the above object, an embodiment of the present invention provides a control method applied to a power supply device. The power supply device includes a power unit and a control unit, and the control method includes the following steps. First, prepare an electrolytic cell having an electrolytic solution, install an anode and a cathode in the electrolytic solution, and install a metal foil on the anode. Next, connect the output terminals of the power unit to the anode and the cathode, and the power unit outputs an output voltage for forming the metal foil. Then, the control unit controls the power unit such that the output voltage has a constant voltage region, a rising voltage pulse region, and a falling voltage pulse region, and the valley value of the falling voltage pulse region satisfies the following relational expression: JPEG0007698090000001.jpg734, where JPEG0007698090000002.jpg67 is the voltage value in the constant voltage region, JPEG0007698090000003.jpg511 is the valley value in the falling voltage pulse region.

[0008] To achieve the above object, another embodiment of the present invention provides a control method applied to a power supply device. The power supply device includes a power unit and a control unit, and the control method includes the following steps. First, prepare an electrolytic cell having an electrolytic solution, install an anode and a cathode in the electrolytic solution, and install a metal foil on the anode. Next, connect the output terminals of the power unit to the anode and the cathode, and the power unit outputs an output current for forming the metal foil. Next, the control unit controls the power unit so that the output current has a constant current region, a rising current pulse region, and a falling current pulse region, and the valley value of the falling current pulse region satisfies the following relational expression, JPEG0007698090000004.jpg732, where, JPEG0007698090000005.jpg67 is the current value in the constant current region, JPEG0007698090000006.jpg59 is the valley value in the falling current pulse region.

[0009] To achieve the above object, another embodiment of the present invention provides a forming system including a power unit, an electrolytic cell, an anode, a cathode, a metal foil, and a control unit. The power unit is provided with at least one output terminal and outputs an output voltage. The electrolytic cell contains an electrolytic solution. The anode is installed in the electrolytic solution and is connected to at least one output terminal of the power unit. The cathode is installed in the electrolytic solution and is connected to at least one output terminal of the power unit. The metal foil is installed on the anode and is formed according to the output voltage. The control unit is connected to the power unit and controls the power unit so that the output voltage has a constant voltage region, a rising voltage pulse region, and a falling voltage pulse region, and the valley value of the falling voltage pulse region satisfies the following relational expression, JPEG0007698090000007.jpg834, where, JPEG0007698090000008.jpg67 is the voltage value in the constant voltage region, JPEG0007698090000009.jpg511 is the valley value in the voltage drop pulse region.

[0010] To achieve the above object, another embodiment of the present invention provides a forming system including a power unit, an electrolytic cell, an anode, a cathode, a metal foil, and a control unit. The power unit is provided with at least one output terminal and outputs an output current. The electrolytic cell contains an electrolytic solution. The anode is installed in the electrolytic solution and connected to at least one output terminal of the power unit. The cathode is installed in the electrolytic solution and connected to at least one output terminal of the power unit. The metal foil is installed on the anode and is formed according to the output current. The control unit is connected to the power unit and controls the power unit so that the output current has a constant current region, a rising current pulse region, and a falling current pulse region. The valley value in the falling current pulse region satisfies the following relational expression, JPEG0007698090000010.jpg731, where, JPEG0007698090000011.jpg67 is the current value in the constant current region, JPEG0007698090000012.jpg59 is the valley value in the falling current pulse region.

[0011] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments, but the present invention is not limited thereto.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2A

Figure 2B

Figure 3A

Figure 3B

Figure 3C

Figure 4A

Figure 4B

Figure 5A

Figure 5B

Figure 6A

Figure 6B

Figure 7A

Figure 7B

Figure 7C

Figure 8A

Figure 8B

Embodiments for Carrying Out the Invention

[0013] Some typical embodiments showing the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various changes in different aspects, all without departing from the scope of the present invention, and the description and drawings are essentially used for illustration and are not intended to limit the present invention.

[0014] Referring to FIG. 1, it is a structural schematic diagram of the formation system of the present invention. As shown in FIG. 1, the formation system 1 of the present invention includes a power supply device, an electrolytic cell 2, a cathode 4, an anode 5, and a metal foil 7. The power supply device includes a power unit 3 and a control unit 6. There is an electrolytic solution 21 in the electrolytic cell 2, and the electrolytic solution 21 is an acidic solution having a medium dissolving power such as phosphoric acid, oxalic acid, boric acid, chromic acid, and citric acid. The power unit 3 is provided with two output terminals 31 and 32, and outputs an output voltage and an output current through the two output terminals 31 and 32. The cathode 4 may be composed of an aluminum foil, is installed in the electrolytic solution 21 of the electrolytic cell 2, and is connected to the output terminal 31 of the power unit 3. The anode 5 is composed of high-purity aluminum, the number of anodes 5 is plural, at least one anode 5 is installed in the electrolytic solution 21 of the electrolytic cell 2, at least one anode 5 is not installed in the electrolytic solution 21 of the electrolytic cell 2, and is connected to the output terminal 32 of the power unit 3. The metal foil 7 is installed on the anode 5. The control unit 6 is connected to the power unit 3, controls the power unit 3, adjusts the output voltage and output current supplied from the power unit 3, and controls the formation process of the metal foil 7. Details of the control unit 6 controlling the output voltage and output current supplied from the power unit 3 will be described later. Hereinafter, the formation process of the metal foil 7 will be described with reference to the drawings.

[0015] Referring to FIGS. 2A and 2B in conjunction with FIG. 1, FIG. 2A is a partially enlarged schematic view showing the structure of corrosion pits formed on the metal foil of the formation system shown in FIG. 1, and FIG. 2B is a partially enlarged schematic view showing the structure of the oxide film formed on the metal foil of the formation system shown in FIG. 1. In FIGS. 2A and 2B, the partial structure of the contact surface between the metal foil 7 of FIG. 1 and the electrolyte 21 in the electrolytic cell 2 in different cases is shown. As the formation process of the metal foil 7, the power unit 3 continuously supplies an output voltage and an output current to the metal foil 7, causing an oxidation reaction on the surface of the metal foil 7 to form an oxide film 8 (as shown in FIG. 2B). At this time, the chemical reaction formula occurring on the metal foil 7 is specifically the electrolysis of water H2O → O 2- + 2H + (This reaction is an exothermic reaction), the ionization of Al metal Al → 3e - + Al 3+ , the formation of aluminum oxide 2Al 3+ + 3O 2- → Al2O3 + 1670 kJ (This reaction is an exothermic reaction). At the same time, the impurity borate ions in the electrolyte also undergo an oxidation reaction with aluminum ions to form BO3 3- + Al 3+ → AlBO3, and due to the oxidation reaction of the impurity ions, the fracture resistance of the oxide film 8 decreases and the quality of the oxide film 8 deteriorates. At the cathode 4, mainly the reduction reaction of hydrogen 2H + + 2e → H2 occurs. Heat accumulates due to the electrolysis of water and oxidation reaction of the metal foil 7, and a side reaction of aluminum oxide dissolution occurs due to high temperature, that is, the electrolyte 21 further corrodes the oxide film 8 formed on the metal foil 7, and Al2O3 + 6H + → 2Al 3+ + 3H2O, damaging the oxide layer.

[0016] Hereinafter, the process of forming and dissolving the oxide film 8 will be further described by dividing it into three stages. The first stage is to form the non-porous layer of the oxide film 8. In the initial stage when the power unit 3 supplies the output voltage and output current, for example, within the first few seconds to several tens of seconds, a dense and highly insulating oxide film 8 is formed on the surface of the metal foil 7. The oxide film 8 is a thin film layer with a thickness of about 0.01 - 0.1 μm and no continuous pores that can prevent the flow of current. Also, the thickness of the non-porous layer is proportional to the output voltage and inversely proportional to the dissolution rate of the oxide film 8 in the electrolytic solution 21. Therefore, the voltage at this stage rapidly increases from zero to the maximum value. The second stage is to form the porous layer of the oxide film 8. As the oxide film 8 is formed, the electrolytic solution 21 begins to dissolve the oxide film 8. However, since the formation of the oxide film 8 is non-uniform, the thinnest part of the oxide film 8 dissolves first to form holes, and the electrolytic solution 21 continues the chemical reaction with the metal foil 7 through these holes, and a porous layer is formed on the oxide film 8. The third stage is to thicken the porous layer of the oxide film 8. When the non-porous layer continues to dissolve and the porous layer is formed, a new non-porous layer continues to grow. Therefore, the formation rate and dissolution rate of the non-porous layer of the oxide film 8 are balanced, the increase in the thickness of the non-porous layer stops, and the voltage change becomes small. However, since the formation and dissolution of the oxide film 8 at the bottom of the holes do not stop, the holes become deeper and pores are formed, and the oxide film 8 with pores continues to thicken. When the formation rate and dissolution rate of the oxide film 8 reach a dynamic balance, the thickness of the oxide film 8 does not change.

[0017] In the process of forming and dissolving the oxide film 8, if there are defects in the oxide film 8, there may be reliability problems in the aluminum electrolytic capacitor. For example, during the load process, the aluminum electrolytic capacitor repairs the oxide film 8 with the electrolyte and thickens it, resulting in an increase in the loss of the electrolyte, an increase in viscosity, an increase in resistivity. As a result, the equivalent series resistance of the electrolyte increases, and the loss of the aluminum electrolytic capacitor increases significantly. In addition, as the viscosity of the electrolyte increases and the metal foil 7 becomes uneven due to the corrosive action, it becomes difficult for the electrolyte to come into sufficient contact with the oxide film 8. As a result, the effective area of the electrode plate of the aluminum electrolytic capacitor decreases, the capacitance decreases rapidly, and furthermore, the life of the aluminum electrolytic capacitor becomes shorter. Also, gas is generated by the electrolysis action during the formation of the oxide film 8, and the gas increases as the formation time becomes longer. Since the aluminum electrolytic capacitor is likely to expand, leak liquid or explode, the quality of the oxide film 8 directly affects the performance of the aluminum electrolytic capacitor. Hereinafter, the parameters related to the quality of the oxide film 8 in the aluminum electrolytic capacitor and its characteristics will be further described.

[0018] Referring to FIGS. 3A, 3B and 3C in conjunction with FIG. 1, FIG. 3A is a simplified structural schematic diagram of an aluminum electrolytic capacitor, FIG. 3B is an equivalent circuit configuration diagram of an aluminum electrolytic capacitor, and FIG. 3C is a simplified equivalent circuit configuration diagram of an aluminum electrolytic capacitor. As shown in FIGS. 3A and 3B, Ca in the figure is the anode capacitance of the aluminum electrolytic capacitor, Cc is the cathode capacitance of the aluminum electrolytic capacitor, Ce is the equivalent capacitance of the electrolyte, Rs is the equivalent conduction resistance (the equivalent conduction resistance includes dielectric loss and metal conductor resistance), Rdc1 is the equivalent dielectric leakage current resistance, Re is the equivalent resistance of the electrolyte and the electrolytic paper, and ESL is the equivalent inductance (the equivalent inductance includes the inductance of the wound metal foil and the lead wire). As shown in FIG. 3C, the equivalent conduction resistance Rs and the equivalent resistance Re of the electrolyte can be combined into a simplified resistance ESR. Also, since the cathode capacitance Cc is much larger than the anode capacitance Ca and the anode capacitance Ca is much larger than the equivalent capacitance Ce of the electrolyte, in FIG. 3C, the cathode capacitance Cc and the equivalent capacitance Ce of the electrolyte can be ignored, and only the anode capacitance Ca is shown.

[0019] As can be seen from FIG. 3C, the dielectric of the oxide film 8 has a great influence on blocking direct current. Since the electrolyte is impregnated in the dielectric of the oxide film 8, when a direct voltage is applied, a small current is generated when reforming and repairing the oxide film, which is called leakage current. The more defects there are in the oxide film 8, the larger the leakage current becomes. Due to the repair reaction of the oxide film 8, the limited electrolyte in the aluminum electrolytic capacitor is consumed and depleted. Referring to FIGS. 4A and 4B together with FIG. 1, FIG. 4A is a waveform diagram of the leakage current of the aluminum electrolytic capacitor, and FIG. 4B is a waveform diagram of the output voltage and output current supplied from the power unit of the power supply device of the formation system shown in FIG. 1. The solid line in FIG. 4B shows the waveform diagram of the output current supplied from the power unit 3, and the broken line shows the waveform diagram of the output voltage supplied from the power unit 3. As shown in FIG. 4B, when the time for the power unit 3 to supply the output voltage and output current is longer than a predetermined value, for example, after several tens of seconds, the output current supplied from the power unit 3 decreases to a steady state, and the formation process of the metal foil 7 becomes a steady state. In the leakage current stage with the minute current value, the defective portions where the oxide film 8 on the metal foil 7 is insufficient dynamically undergo dissolution and oxidation reactions until a new oxide film is formed.

[0020] Therefore, in order to avoid the reliability problems in the formation and dissolution process of the oxide film 8 and improve the quality of the oxide film 8, hereinafter, the present invention will further explain improving the quality of the oxide film 8 by adjusting the output voltage or output current supplied from the power unit 3. Referring to FIG. 5A together with FIG. 1, FIG. 5A is a voltage-current waveform diagram of the first embodiment of the output voltage and output current supplied from the power unit of the power supply device of the formation system shown in FIG. 1. In this embodiment, the control unit 6 controls the output voltage of the power unit 3 to have a constant voltage region V1, a rising voltage pulse region V2, and a falling voltage pulse region V3. The constant voltage region V1, the rising voltage pulse region V2, and the falling voltage pulse region V3 of the output voltage are constant, and the peak value of the rising voltage pulse region V2 and the valley value of the falling voltage pulse region V3 satisfy the following relational expressions respectively. JPEG0007698090000013.jpg1459 Here, JPEG0007698090000014.jpg67 is the voltage value of the constant voltage region V1, and the ripple coefficient of the constant voltage region V1 ≤ ±2%, JPEG0007698090000015.jpg511 is the peak value of the rising voltage pulse region V2, JPEG0007698090000016.jpg511 is the valley value of the falling voltage pulse region V3, JPEG0007698090000017.jpg68 is the voltage adjustment range coefficient preset in the control unit 6, JPEG0007698090000018.jpg637. In this embodiment, the peak value of the rising voltage pulse region V2 JPEG0007698090000019.jpg511 has a magnitude that is JPEG0007698090000020.jpg511 different from the magnitude of the valley value of the falling voltage pulse region V3.

[0021] When the control unit 6 controls the output voltage of the power unit 3 to be in the rising voltage pulse region V2, the output current of the power unit 3 becomes the corresponding rising current. At this time, the electric field strength on the oxide film 8 increases, so that the weak defect regions (for example, impurity defects, crack defects, and the outermost hydrated aluminum oxide layer) in the oxide film 8 are sufficiently destroyed to promote dissolution, the fresh aluminum base material of the metal foil 7 is exposed, the dynamic repair time is shortened, and an energy-saving effect is achieved. When the control unit 6 controls the output voltage of the power unit 3 to be in the falling voltage pulse region V3, the output current of the power unit 3 becomes the corresponding falling current. At this time, the electric field strength on the oxide film 8 decreases, so that the heat accumulation on the metal foil 7 is prevented, the temperature of the metal foil 7 is lowered, thereby suppressing the dissolution side reaction of the oxide film 8, preventing the dissolution region from expanding, reducing the damage to the oxide film 8, and weakening the oxidation reaction of impurity ions, and reducing the impurities in the oxide film 8. When the control unit 6 controls the output voltage of the power unit 3 to be in the constant voltage region V1, the output current of the power unit 3 also becomes a constant current state. The oxide film 8 regenerates and fills the dissolution region, so that the oxide film 8 becomes denser and the quality is improved.

[0022] As can be seen from the relational expression that the valley value of the falling voltage pulse region V3 should satisfy, the valley value of the falling voltage pulse region V3 needs to be greater than 0, whereby it can be ensured that the electrode polarity in the electrolytic cell 2 does not reverse. For example, it can be ensured that the cathode does not become the anode, and it can be avoided that the metal material (such as stainless steel) of the cathode plate device is corroded and dissolved due to the reversal of the polarity, damaging the existing equipment and having poor compatibility. Also, when the lower limit of the falling voltage pulse region is greater than the amplitude "zero" and close to the amplitude "zero", a greater local voltage dip effect occurs, the dissolution process of the defect part can be completed more quickly, and sufficient time can be given for subsequent re-oxidation and repair.

[0023] In addition, in order to ensure an appropriate and sufficient dissolution time and oxidation time, the pulse width time of the rising voltage pulse region V2 and the pulse width time of the falling voltage pulse region V3 need to be adjusted within a preset range. Continuing to refer to FIG. 5A, in this embodiment, the rising voltage pulse region V2 is continuous with the next adjacent falling voltage pulse region V3, and the time from the starting point A1 of the pulse width time of the rising voltage pulse region V2 to the ending point A2 of the pulse width time of the next adjacent falling voltage pulse region V3 is 1 to 100 seconds. That is, the frequencies of the rising voltage pulse region V2 and the falling voltage pulse region V3 are 0.01 to 1 Hz. In this embodiment, the rising voltage pulse region V2 includes one rising voltage pulse, and the falling voltage pulse region V3 includes one falling voltage pulse. In some other embodiments, the rising voltage pulse region V2 includes a plurality of rising voltage pulses, and the falling voltage pulse region V3 includes a plurality of falling voltage pulses. In some other embodiments, the next adjacent falling voltage pulse region V3 to the rising voltage pulse region V2 may be discontinuous, and may be a plurality of combinations that are symmetric or asymmetric, adjacent or intermittent. In this case, the time from the starting point A1 of the pulse width time of the rising voltage pulse region V2 to the ending point A2 of the pulse width time of the next adjacent falling voltage pulse region V3 also needs to be 1 to 100 seconds. In some embodiments, the falling voltage pulse region V3 is located before the adjacent rising voltage pulse region V2. In this case, the time from the starting point of the pulse width time of the falling voltage pulse region V3 to the ending point of the pulse width time of the next adjacent rising voltage pulse region V2 also needs to be 1 to 100 seconds.

[0024] Refer to FIG. 5B in combination with FIGS. 1 and 5A. FIG. 5B is a flowchart of a method for controlling the output voltage and output current supplied from the power unit of the formation system shown in FIG. 5A. First, execute step S1, prepare an electrolytic cell 2 having an electrolytic solution 21, install an anode 5 and a cathode 4 in the electrolytic solution 21, and install a metal foil 7 on the anode 5. Next, execute step S2, connect the output terminals 31, 32 of the power unit 3 to the anode 5 and the cathode 4, and the power unit 3 outputs an output voltage for forming the metal foil 7. Then, execute step S3, and the control unit 6 controls the power unit 3 so that the output voltage has a constant voltage region V1, a rising voltage pulse region V2, and a falling voltage pulse region V3. The valley value of the falling voltage pulse region V3 satisfies the following relational expression, JPEG0007698090000021.jpg734, where, JPEG0007698090000022.jpg67 is the voltage value of the constant voltage region V1, JPEG0007698090000023.jpg511 is the valley value of the falling voltage pulse region V3.

[0025] Refer to FIG. 6A in combination with FIG. 1. FIG. 6A is a voltage-current waveform diagram of a second embodiment of the output voltage and output current supplied from the power unit of the formation system shown in FIG. 1. In this embodiment, the control unit 6 controls the output current of the power unit 3 to have a constant current region I1, a rising current pulse region I2, and a falling current pulse region I3. The constant current region I1, the rising current pulse region I2, and the falling current pulse region I3 of the output current are constant, and the peak value of the rising current pulse region I2 and the valley value of the falling current pulse region I3 satisfy the following relational expressions respectively. JPEG0007698090000024.jpg1355 Here, JPEG0007698090000025.jpg67 is the current value of the constant current region I1, and the ripple coefficient of the constant current region I1 ≤ ±2%, JPEG0007698090000026.jpg510 is the peak value of the rising current pulse region I2, JPEG0007698090000027.jpg59 is the valley value of the descending current pulse region I3, JPEG0007698090000028.jpg68 is the adjustment range coefficient of the current preset in the control unit 6, JPEG0007698090000029.jpg638. In this embodiment, the peak value JPEG0007698090000030.jpg510 of the ascending current pulse region I2 JPEG0007698090000031.jpg59 of the valley value of the descending current pulse region I3.

[0026] When the control unit 6 controls the output current of the power unit 3 to be in the ascending current pulse region I2, the output voltage of the power unit 3 becomes the corresponding ascending voltage. At this time, the electric field strength on the oxide film 8 increases, so that the weak defect regions (for example, impurity defects, crack defects, the outermost hydrated aluminum oxide layer) in the oxide film 8 are sufficiently destroyed to promote dissolution, the fresh aluminum base material of the metal foil 7 is exposed, the dynamic repair time is shortened, and an energy-saving effect is achieved. When the control unit 6 controls the output current of the power unit 3 to be in the descending current pulse region I3, the output voltage of the power unit 3 becomes the corresponding descending voltage. At this time, the electric field strength on the oxide film 8 decreases, so that the heat accumulation on the metal foil 7 is prevented, the temperature of the metal foil 7 is decreased, thereby suppressing the dissolution side reaction of the oxide film 8, preventing the dissolution region from expanding, reducing the damage to the oxide film 8, weakening the oxidation reaction of impurity ions, and reducing the impurities in the oxide film 8. When the control unit 6 controls the output current of the power unit 3 to be in the constant current region I1, the output voltage of the power unit 3 also becomes a constant voltage state. The oxide film 8 is regenerated to fill the dissolution region, so that the oxide film 8 becomes denser and the quality is improved.

[0027] As can be seen from the relational expression that the valley value of the falling current pulse region I3 should satisfy, the valley value of the falling current pulse region I3 needs to be greater than 0. Thereby, it can be ensured that the electrode polarity in the electrolytic cell 2 does not reverse. For example, it can be ensured that the cathode does not become the anode, and it can be avoided that the metal material (such as stainless steel) of the cathode plate device is corroded and dissolved due to the reversal of the polarity, damaging the existing equipment and having poor compatibility. Also, when the lower limit of the falling current pulse region I3 is greater than the amplitude "zero" and close to the amplitude "zero", a greater local current dip effect occurs, which can complete the dissolution process of the defective part more quickly and give sufficient time for subsequent reoxidation and repair.

[0028] Also, in order to ensure appropriate and sufficient dissolution time and oxidation time, the pulse width time of the rising current pulse region I2 and the pulse width time of the falling current pulse region I3 need to be adjusted within a preset range. Continuing to refer to FIG. 6A, in this embodiment, the rising current pulse region I2 is continuous with the next adjacent falling current pulse region I3, and the time from the start point B1 of the pulse width time of the rising current pulse region I2 to the end point B2 of the pulse width time of the next adjacent falling current pulse region I3 is 1 to 100 seconds, that is, the frequencies of the rising current pulse region I2 and the falling current pulse region I3 are 0.01 to 1 Hz. In this embodiment, the rising current pulse region I2 includes one rising current pulse, and the falling current pulse region I3 includes one falling current pulse. In some embodiments, the rising current pulse region I2 includes a plurality of rising current pulses, and the falling current pulse region I3 includes a plurality of falling current pulses. In some other embodiments, the next adjacent falling current pulse region I3 to the rising current pulse region I2 may be discontinuous, and may be a plurality of combinations that are symmetric or asymmetric, adjacent or intermittent. In this case, the time from the start point B1 of the pulse width time of the rising current pulse region I2 to the end point B2 of the pulse width time of the next adjacent falling current pulse region I3 also needs to be 1 to 100 seconds.

[0029] Referring to FIGS. 1, 6A and 6B together, FIG. 6B is a flowchart of a method for controlling the output voltage and output current supplied from the power unit of the formation system shown in FIG. 6A. First, step M1 is executed to prepare an electrolytic cell 2 having an electrolytic solution 21, install an anode 5 and a cathode 4 in the electrolytic solution 21, and install a metal foil 7 on the anode 5. Next, step M2 is executed to connect the output terminals 31, 32 of the power unit 3 to the anode 5 and the cathode 4, and the power unit 3 outputs an output current for forming the metal foil 7. Then, step M3 is executed, and the control unit 6 controls the power unit 3 such that the output current has a constant current region I1, a rising current pulse region I2, and a falling current pulse region I3, and the valley value of the falling current pulse region I3 satisfies the following relational expression, JPEG0007698090000032.jpg732, where JPEG0007698090000033.jpg67 is the current value of the constant current region I1, JPEG0007698090000034.jpg59 is the valley value of the falling current pulse region I3.

[0030] In some embodiments, the rising voltage pulse region and the falling voltage pulse region are not limited to being constant, and may be curved or stepped. Of course, the rising current pulse region and the falling current pulse region are also not limited to being constant, and may be curved or stepped. By using a stepped pulse region, the oxide film 8 can be made dense, the subsequent repair time of the oxide film 8 can be shortened, and the power consumption per unit area can be reduced. Referring to FIG. 7A, it is a voltage-current waveform diagram of a third embodiment of the output voltage and output current supplied from the power unit of the formation system shown in FIG. 1. In this embodiment, when the control unit 6 controls the output voltage of the power unit 3 to be in the rising voltage pulse region V2, the output current of the power unit 3 becomes the corresponding rising current. The rising voltage pulse region V2 of this embodiment is stepped, and the plurality of steps (for example, the two steps shown in FIG. 7A) of the rising voltage pulse region V2 each have a corresponding peak value, and the step with the highest peak value in the rising voltage pulse region V2 is It is JPEG0007698090000035.jpg511. When the control unit 6 controls the output voltage of the power unit 3 to be in the step-down voltage pulse region V3, the output current of the power unit 3 becomes the corresponding step-down current. The step-down voltage pulse region V3 of this embodiment is stepped, and a plurality of steps of the step-down voltage pulse region V3 (for example, the two steps shown in FIG. 7A) each have a corresponding valley value, and the step with the lowest valley value in the step-down voltage pulse region V3 is It is JPEG0007698090000036.jpg511.

[0031] Referring to FIG. 7B, it is a voltage-current waveform diagram of a fourth embodiment of the output voltage and output current supplied from the power unit of the power supply device of the formation system shown in FIG. 1. In this embodiment, when the control unit 6 controls the output voltage of the power unit 3 to be in the step-up voltage pulse region V2, the output current of the power unit 3 becomes the corresponding step-up current. The step-up voltage pulse region V2 of this embodiment is stepped, and a plurality of steps of the step-up voltage pulse region V2 (for example, the single step shown in FIG. 7B) each have a corresponding peak value, and the step with the highest peak value in the step-up voltage pulse region V2 is It is JPEG0007698090000037.jpg511. When the control unit 6 controls the output voltage of the power unit 3 to be in the step-down voltage pulse region V3, the output current of the power unit 3 becomes the corresponding step-down current. The step-down voltage pulse region V3 of this embodiment is intermittent. For example, the step-down voltage pulse region V3 shown in FIG. 7B has two step-down voltage pulses, and the voltages on both sides of each step-down voltage pulse are equal to the voltage in the constant voltage region. The step with the lowest valley value in the step-down voltage pulse region V3 is It is 511 for JPEG0007698090000038.jpg, and there is a constant voltage region between two intermittent waveforms. Of course, in some embodiments, the control unit 6 can control the rising voltage pulse region V2 intermittently, that is, the rising voltage pulse region V2 includes a plurality of rising voltage pulses, and the voltages on both sides of each rising voltage pulse are equal to the voltage of the constant voltage region. Since the formation method is the same as that of the falling voltage pulse region V3, the description is omitted here. In some embodiments, the rising current pulse region includes a plurality of rising current pulses, and the currents on both sides of each rising current pulse are equal to the current of the constant current region. In some embodiments, the falling current pulse region includes a plurality of falling current pulses, and the currents on both sides of each falling current pulse are equal to the current of the constant current region.

[0032] Referring to FIG. 7C, it is a voltage-current waveform diagram of a fifth embodiment of the output voltage and output current supplied from the power unit of the formation system shown in FIG. 1. In this embodiment, when the control unit 6 controls the output current of the power unit 3 to be in the rising current pulse region I2, the output voltage of the power unit 3 becomes the corresponding rising voltage. The rising current pulse region I2 of this embodiment is in a stepped shape, and the plurality of steps (for example, the two steps shown in FIG. 7C) of the rising current pulse region I2 each have corresponding peak values. The step with the highest peak value in the rising current pulse region I2 is It is 510 for JPEG0007698090000039.jpg. When the control unit 6 controls the output current of the power unit 3 to be in the falling current pulse region I3, the output voltage of the power unit 3 becomes the corresponding falling voltage. The falling current pulse region I3 of this embodiment is in a stepped shape, and the plurality of steps (for example, the two steps shown in FIG. 7C) of the falling current pulse region I3 each have corresponding valley values. The step with the lowest valley value in the falling current pulse region I3 is It is JPEG0007698090000040.jpg59. A multi-step or intermittent waveform can generate a dynamic process of multiple polarizations, depolarizations, and restorations, making the oxide film 8 denser and reducing defects, while shortening the formation time required for the subsequent restoration process, that is, reducing the power consumption per unit area.

[0033] To improve the dielectric quality of the barrier layer in the oxide film 8, the voltage in the rising voltage pulse region V2 contains a high-frequency ripple component, and / or the voltage in the falling voltage pulse region V3 contains a high-frequency ripple component. By injecting ripples, the electric field is periodically changed to avoid impurities in the metal foil 7 and improve the quality of the oxide film 8. Referring to Fig. 8A, it is a voltage waveform diagram of the sixth embodiment of the output voltage supplied from the power unit of the power supply device of the formation system shown in Fig. 1. As shown in the figure, the voltage in the rising voltage pulse region V2 of this embodiment contains a high-frequency ripple component, and each high-frequency ripple component is the peak value of the rising voltage pulse region V2 JPEG0007698090000041.jpg511 is smaller, the voltage in the falling voltage pulse region V3 contains a high-frequency ripple component and a low-frequency ripple component, each high-frequency ripple component is the valley value of the falling voltage pulse region V3 JPEG0007698090000042.jpg511 is larger, the range of the high-frequency ripple component is 50 Hz to 500 kHz, and the range of the low-frequency ripple component is 0.01 Hz to 1 Hz. The dynamic restoration of the oxide film 8 is promoted by using ripple stress.

[0034] Of course, in one embodiment, the voltage in the rising current pulse region I2 may contain a high-frequency ripple component, and / or the voltage in the falling current pulse region I3 may contain a high-frequency ripple component. Referring to Fig. 8B, it is a current waveform diagram of the seventh embodiment of the output current supplied from the power unit of the power supply device shown in Fig. 1. As shown in the figure, the voltage in the rising current pulse region I2 of this embodiment contains a high-frequency ripple component, and each high-frequency ripple component is the peak value of the rising current pulse region I2 Smaller than JPEG0007698090000043.jpg510, the voltage in the falling current pulse region I3 includes high-frequency ripple components and low-frequency ripple components, and each high-frequency ripple component is the valley value of the falling current pulse region I3 Larger than JPEG0007698090000044.jpg59, the range of the high-frequency ripple component is 50 Hz to 500 kHz, and the range of the low-frequency ripple component is 0.01 Hz to 1 Hz. The high-frequency ripple component here simulates the high-frequency ripple stress of the actual circuit where the electrolytic capacitor is placed, utilizes the local hot spots due to high-frequency dielectric loss to accelerate the destruction and dissolution of the defect points, and then fills the high-frequency defect part with the newly generated oxide film to promote the dynamic repair of the oxide film 8. Thereby, the quality of the oxide film 8 can be fundamentally improved, and the consumption of the electrolytic solution due to the dynamic repair of the electrolytic capacitor in applications with high-frequency ripple can be prevented.

[0035] As described above, the present invention provides a power supply device and a control method thereof. By controlling, with a control unit, the output voltage output by a power unit to have a rising voltage pulse region, a falling voltage pulse region, and a constant voltage region, or by controlling the output current output by the power unit to have a rising current pulse region, a falling current pulse region, and a constant current region, respectively, weak portions of the oxide film are broken, the processes of dissolution and destruction are retarded, and the effect of regenerating the metal foil to fill the dissolved portions is achieved. Thereby, the quality of the oxide film is improved, and further, the capacitance and lifespan of the aluminum electrolytic capacitor are improved. Also, as can be understood from the relational expression that the valley value of the falling voltage pulse region (or the falling current pulse region) should satisfy, the valley value of the falling voltage pulse region (or the falling current pulse region) needs to be greater than 0. Thereby, it can be ensured that the electrode polarity in the electrolytic cell does not reverse, and further, corrosion and dissolution of the metal material constituting the cathode can be avoided. Also, since the valley value of the falling voltage pulse region is much lower than the peak value of the rising voltage pulse region, and the valley value of the falling current pulse region is much lower than the peak value of the rising current pulse region, a large local voltage and current dip effect is generated to rapidly complete the depolarization and dissolution processes of the oxide film, shorten the dynamic repair time, and reduce the energy consumption of the entire power supply device.

[0036] Of course, the present invention can also have various other embodiments without departing from the spirit and essence of the present invention, and those skilled in the art can make various corresponding changes and modifications according to the present invention. However, these corresponding changes and modifications should be deemed to fall within the protection scope of the claims of the present invention.

Description of Reference Numerals

[0037] 1: Power supply device 2: Electrolytic cell 21: Electrolyte 3: Power unit 31, 32: Output terminals 4: Cathode 5: Anode 6: Control unit 7: Metal foil 8: Oxide film Ca: Anode capacitance Cc: Cathode capacitance Ce: Equivalent capacitance of the electrolyte Rs: Equivalent conduction resistance Rdc1: Equivalent dielectric leakage current resistance Re: Equivalent resistance of the electrolyte and the electrolytic paper ESL: Equivalent inductance V1: Constant voltage region V2: Rising voltage pulse region V3: Falling voltage pulse region JPEG0007698090000045.jpg511: Peak value of the rising voltage pulse region JPEG0007698090000046.jpg511: Trough value of the falling voltage pulse region I1: Constant current region I2: Rising current pulse region I3: Falling current pulse region JPEG0007698090000047.jpg510: Peak value of the rising current pulse region JPEG0007698090000048.jpg59: Trough value of the falling current pulse region S1 - S3, M1 - M3: Processes

Claims

1. A control method applied to a power supply device, comprising: The power supply device includes a power unit and a control unit. The control method includes: preparing an electrolytic cell containing an electrolytic solution, placing an anode and a cathode in the electrolytic solution, and placing a metal foil on the anode; an output terminal of the power unit is connected to the anode and the cathode, and the power unit outputs an output voltage for chemically converting the metal foil; The control unit controls the power unit so that the output voltage has a constant voltage region, an increasing voltage pulse region, and a decreasing voltage pulse region, and a valley value of the decreasing voltage pulse region satisfies the following relationship: Where: is the voltage value of the constant voltage region, is a valley value of the drop voltage pulse region; A control method comprising:

2. 2. The control method according to claim 1, wherein the time from the start of the rising voltage pulse region to the end of the adjacent falling voltage pulse region is 1 to 100 seconds, or the time from the start of the falling voltage pulse region to the end of the adjacent rising voltage pulse region is 1 to 100 seconds.

3. 2. The method of claim 1, wherein the voltage of the rising voltage pulse region is constant, curvilinear or stepped, and / or the voltage of the falling voltage pulse region is constant, curvilinear or stepped.

4. 2. The method of claim 1, wherein the voltage of the rising voltage pulse region includes a high frequency ripple component, and / or the voltage of the falling voltage pulse region includes a high frequency ripple component, and the high frequency ripple component is in the range of 50 Hz to 500 kHz.

5. 2. The method of claim 1, wherein the rising voltage pulse region includes one or more rising voltage pulses and the falling voltage pulse region includes one or more falling voltage pulses, and the rising voltage pulse region and the falling voltage pulse region are contiguous.

6. The peak value of the rising voltage pulse region satisfies the following relationship: Where: is the peak value of the rising voltage pulse region, The control method according to claim 1 .

7. 2. The method of claim 1, wherein the rising voltage pulse region includes one or more rising voltage pulses, the falling voltage pulse region includes one or more falling voltage pulses, and the constant voltage region is included between the rising voltage pulse region and the falling voltage pulse region.

8. A control method applied to a power supply device, comprising: The power supply device includes a power unit and a control unit. The control method includes: preparing an electrolytic cell containing an electrolytic solution, placing an anode and a cathode in the electrolytic solution, and placing a metal foil on the anode; an output terminal of the power unit is connected to the anode and the cathode, and the power unit outputs an output current for chemically converting the metal foil; The control unit controls the power unit so that the output current has a constant current region, a rising current pulse region, and a falling current pulse region, and a valley value of the falling current pulse region satisfies the following relationship: Where: is the current value in the constant current region, is a valley value of the falling current pulse region; A control method comprising:

9. 9. The control method according to claim 8, wherein the time from the start of the rising current pulse region to the end of the adjacent falling current pulse region is 1 to 100 seconds, or the time from the start of the falling current pulse region to the end of the adjacent rising current pulse region is 1 to 100 seconds.

10. 9. The method of claim 8, wherein the current in the rising current pulse region is constant, curvilinear or stepped, and / or the current in the falling current pulse region is constant, curvilinear or stepped.

11. 9. The control method according to claim 8, wherein the current in the rising current pulse region includes a high frequency ripple component, and / or the current in the falling current pulse region includes a high frequency ripple component, and the high frequency ripple component is in the range of 50 Hz to 500 kHz.

12. 9. The method of claim 8, wherein the rising current pulse region includes one or more rising current pulses and the falling current pulse region includes one or more falling current pulses, and the rising current pulse region and the falling current pulse region are contiguous.

13. The peak value of the rising current pulse region satisfies the following relationship: Where: is the peak value of the rising current pulse region, The control method according to claim 8 .

14. 9. The method of claim 8, wherein the rising current pulse region includes one or more rising current pulses and the falling current pulse region includes one or more falling current pulses, and the constant current region is included between the rising current pulse region and the falling current pulse region.

15. a power unit having at least one output terminal and outputting an output voltage; an electrolytic cell having an electrolyte; an anode disposed in the electrolyte and connected to the at least one output terminal of the power unit; a cathode disposed in the electrolyte and connected to the at least one output terminal of the power unit; a metal foil disposed on the anode and chemically converted in response to the output voltage; a control unit, connected to the power unit, for controlling the power unit such that the output voltage has a constant voltage region, an increasing voltage pulse region, and a decreasing voltage pulse region, wherein a valley value of the decreasing voltage pulse region satisfies the following relationship: Where: is the voltage value of the constant voltage region, is a valley value of the drop voltage pulse region; and A chemical conversion system comprising:

16. 16. The chemical conversion system of claim 15, wherein the time from the start of the rising voltage pulse region to the end of the adjacent falling voltage pulse region is 1 to 100 seconds, or the time from the start of the falling voltage pulse region to the end of the adjacent rising voltage pulse region is 1 to 100 seconds.

17. 16. The conversion system of claim 15, wherein the voltage of the increasing voltage pulse region is constant, curvilinear or stepped, and / or the voltage of the decreasing voltage pulse region is constant, curvilinear or stepped.

18. 16. The chemical conversion system of claim 15, wherein the voltage of the rising voltage pulse region includes a high frequency ripple component, and / or the voltage of the falling voltage pulse region includes a high frequency ripple component, the high frequency ripple component being in the range of 50 Hz to 500 kHz.

19. 16. The chemical conversion system of claim 15, wherein the increasing voltage pulse region includes one or more increasing voltage pulses and the decreasing voltage pulse region includes one or more decreasing voltage pulses, and the increasing voltage pulse region and the decreasing voltage pulse region are contiguous.

20. The peak value of the rising voltage pulse region satisfies the following relationship: Where: is the peak value of the rising voltage pulse region, 16. The conversion system of claim 15,

21. 16. The chemical conversion system of claim 15, wherein the increasing voltage pulse region includes one or more increasing voltage pulses and the decreasing voltage pulse region includes one or more decreasing voltage pulses, and wherein the constant voltage region is included between the increasing voltage pulse region and the decreasing voltage pulse region.

22. a power unit having at least one output terminal and outputting an output current; an electrolytic cell having an electrolyte; an anode disposed in the electrolyte and connected to the at least one output terminal of the power unit; a cathode disposed in the electrolyte and connected to the at least one output terminal of the power unit; a metal foil disposed on the anode and chemically converted in response to the output current; a control unit coupled to the power unit and controlling the power unit such that the output current has a constant current region, a rising current pulse region, and a falling current pulse region, wherein a valley value of the falling current pulse region satisfies the following relationship: Where: is the current value in the constant current region, is a valley value of the falling current pulse region; and A chemical conversion system comprising:

23. 23. The chemical conversion system of claim 22, wherein the time from the beginning of the rising current pulse region to the end of the adjacent falling current pulse region is 1 to 100 seconds, or the time from the beginning of the falling current pulse region to the end of the adjacent rising current pulse region is 1 to 100 seconds.

24. 23. The chemical conversion system of claim 22, wherein the current in the rising current pulse region is constant, curvilinear, or stepped, and / or the current in the falling current pulse region is constant, curvilinear, or stepped.

25. 23. The chemical conversion system of claim 22, wherein the current in the rising current pulse region includes a high frequency ripple component and / or the current in the falling current pulse region includes a high frequency ripple component, the high frequency ripple component being in the range of 50 Hz to 500 kHz.

26. 23. The chemical conversion system of claim 22, wherein the rising current pulse region includes one or more rising current pulses and the falling current pulse region includes one or more falling current pulses, the rising current pulse region and the falling current pulse region being contiguous.

27. The peak value of the rising current pulse region satisfies the following relationship: Where: is the peak value of the rising current pulse region, 23. The conversion system of claim 22, wherein:

28. 23. The chemical conversion system of claim 22, wherein the rising current pulse region includes one or more rising current pulses and the falling current pulse region includes one or more falling current pulses, and the constant current region is included between the rising current pulse region and the falling current pulse region.

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