JP7698090B2 - Power supply device and control method thereof - Google Patents

Description

The present invention relates to a power supply device and a control method thereof, and in particular to a power supply device for chemically converting metal foil and a control method thereof.

An aluminum electrolytic capacitor includes at least a positive electrode, a negative electrode, and an electrolyte. Metal foil is a material used to manufacture the positive and negative electrodes of an aluminum electrolytic capacitor, and is mainly used to store electric charges. Metal foil is made mainly from high-purity aluminum foil, and is formed through a series of processing steps such as corrosion and chemical conversion. The manufacturing process of an aluminum electrolytic capacitor is explained in more detail below. The anode aluminum foil, which has been corroded and covered with a dielectric layer (i.e., an oxide film), the cathode aluminum foil, and electrolytic paper are rolled up, and then immersed in an electrolyte and enclosed in an aluminum case.

The quality of the metal foil has a decisive impact on the overall performance of an aluminum electrolytic capacitor, and the corrosion process and chemical formation process of the metal foil directly determine the performance of the aluminum electrolytic capacitor, such as capacity, leakage current, loss, lifespan, reliability, and volume. For example, the larger the specific volume of the metal foil, the higher the unit charge 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 of the aluminum electrolytic capacitor with the highest technical content and added value.

The chemical formation process is to place the anode aluminum foil in an electrolyte, apply a high DC voltage to the anode aluminum foil, and form an oxide film on the surface of the anode aluminum foil through electrolysis and oxidation. The chemical formation process directly affects the quality of the oxide film, that is, it determines the dielectric constant, leakage current, and withstand voltage of the aluminum electrolytic capacitor by controlling whether the aluminum oxide (γ-Al ₂ O ₃ ) in the oxide film is uniform and dense, or whether there are excess impurity ions in the oxide film, and ultimately determines the capacity and life of the aluminum electrolytic capacitor. Therefore, it is the research goal of those skilled in the art to improve the chemical formation process to improve the quality of the oxide film on the anode aluminum foil.

Therefore, there is currently an urgent need to develop a power supply device and a method for controlling it that will improve the quality of chemical conversion.

The object of the present invention is to provide a power supply device and a control method thereof. The control unit controls the output voltage output by the power unit to have an increasing voltage pulse region, a decreasing voltage pulse region, and a constant voltage region, or controls the output current output by the power unit to have an increasing current pulse region, a decreasing current pulse region, and a constant current region, thereby destroying the weak parts of the oxide film, delaying the process of dissolution and destruction, and regenerating the metal foil to fill the dissolved parts, thereby improving the quality of the oxide film and further improving the capacity and life of the aluminum electrolytic capacitor. In addition, as can be seen from the relationship that the valley value of the decreasing voltage pulse region (or the decreasing current pulse region) should satisfy, the valley value of the decreasing voltage pulse region (or the decreasing current pulse region) must be greater than 0, which can ensure that the electrode polarity in the electrolytic cell is not reversed, and further avoid the corrosion and dissolution of the metal material constituting the cathode. In addition, 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, which can generate a large local voltage and current dip effect to quickly complete the depolarization and dissolution process of the oxide film, shorten the dynamic repair time, and reduce the energy consumption of the entire power supply device.

In order to achieve the above object, one 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, an electrolytic cell containing an electrolyte is prepared, an anode and a cathode are placed in the electrolyte, and a metal foil is placed on the anode. Next, the output terminals of the power unit are connected to the anode and the cathode, and the power unit outputs an output voltage for chemically converting the metal foil. Thereafter, 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 the valley value of the decreasing voltage pulse region satisfies the following relational expression:
, where:
is the voltage value in the constant voltage region,
is the valley value of the falling voltage pulse region.

In order 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, an electrolytic cell containing an electrolyte is prepared, an anode and a cathode are placed in the electrolyte, and a metal foil is placed on the anode. Next, the output terminals of the power unit are connected to the anode and the cathode, and the power unit outputs an output current for chemically forming the metal foil. Next, the control unit controls the power unit so that the output current has a constant current region, an increasing current pulse region, and a decreasing current pulse region, and the valley value of the decreasing current pulse region satisfies the following relational expression:
, where:
is the current value in the constant current region,
is the valley value of the falling current pulse region.

In order to achieve the above object, another embodiment of the present invention provides a chemical formation system including a power unit, an electrolytic cell, an anode, a cathode, a metal foil, and a control unit. The power unit has at least one output terminal and outputs an output voltage. The electrolytic cell has an electrolyte. The anode is disposed in the electrolyte and connected to at least one output terminal of the power unit. The cathode is disposed in the electrolyte and connected to at least one output terminal of the power unit. The metal foil is disposed on the anode and is chemically 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, an increasing voltage pulse region, and a decreasing voltage pulse region, and the valley value of the decreasing voltage pulse region satisfies the following relationship:
, where:
is the voltage value in the constant voltage region,
is the valley value of the falling voltage pulse region.

In order to achieve the above object, another embodiment of the present invention provides a chemical formation system including a power unit, an electrolytic cell, an anode, a cathode, a metal foil, and a control unit. The power unit has at least one output terminal and outputs an output current. The electrolytic cell has an electrolyte. The anode is disposed in the electrolyte and connected to at least one output terminal of the power unit. The cathode is disposed in the electrolyte and connected to at least one output terminal of the power unit. The metal foil is disposed on the anode and is chemically 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, an increasing current pulse region, and a decreasing current pulse region, and the valley value of the decreasing current pulse region satisfies the following relationship:
, where:
is the current value in the constant current region,
is the valley value of the falling current pulse region.

The present invention will be described in detail below with reference to the attached drawings and specific embodiments, but the present invention is not limited thereto.

FIG. 1 is a structural schematic diagram of a chemical conversion system of the present invention. 2 is a partially enlarged schematic diagram showing the structure of corrosion pits formed on the metal foil of the chemical conversion system shown in FIG. 1. 2 is a partially enlarged schematic diagram showing the structure of an oxide film formed on the metal foil of the chemical conversion system shown in FIG. 1. FIG. 1 is a simplified schematic diagram of the structure of an aluminum electrolytic capacitor. FIG. 1 is an equivalent circuit diagram of an aluminum electrolytic capacitor. FIG. 1 is a simplified equivalent circuit diagram of an aluminum electrolytic capacitor. FIG. 1 is a waveform diagram of leakage current of an aluminum electrolytic capacitor. 2 is a waveform diagram of an output voltage and an output current supplied from a power unit of the power supply device of the chemical conversion system shown in FIG. 1 . 2 is a voltage/current waveform diagram of a first embodiment of an output voltage and an output current supplied from a power unit of a power supply device of the chemical conversion system shown in FIG. 1 . FIG. 5B is a flowchart of a method for controlling an output voltage and an output current supplied from a power unit of the power supply device of the chemical conversion system shown in FIG. 5A. 4 is a voltage/current waveform diagram of a second embodiment of the output voltage and output current supplied from a power unit of the power supply device of the chemical conversion system shown in FIG. 1 . FIG. 6B is a flowchart of a method for controlling the output voltage and the output current supplied from the power unit of the power supply device of the chemical conversion system shown in FIG. 6A. 1. FIG. 4 is a voltage/current waveform diagram of a third embodiment of the output voltage and output current supplied from the power unit of the power supply device of the chemical conversion system shown in FIG. 1. FIG. 4 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 chemical conversion system shown in FIG. 1. FIG. 14 is a voltage/current waveform diagram of a fifth embodiment of the output voltage and output current supplied from the power unit of the power supply device of the chemical conversion system shown in FIG. FIG. 13 is a voltage waveform diagram of a sixth embodiment of an output voltage supplied from a power unit of a power supply device of the chemical conversion system shown in FIG. FIG. 13 is a current waveform diagram of a seventh embodiment of an output current supplied from a power unit of a power supply device of the chemical conversion system shown in FIG.

Some exemplary embodiments illustrating the features and advantages of the present invention are described in detail in the following description. It is to be understood that the present invention can have various modifications in different aspects, all without departing from the scope of the present invention, and that the description and drawings are used for illustrative purposes only and are not intended to limit the present invention.

Referring to FIG. 1, this is a schematic diagram of the structure of the chemical conversion system of the present invention. As shown in FIG. 1, the chemical conversion 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 electrolyte 21 in the electrolytic cell 2, and the electrolyte 21 is an acidic solution having a moderate dissolving power, such as phosphoric acid, oxalic acid, boric acid, chromic acid, and citric acid. The power unit 3 has 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 made of aluminum foil, and is installed in the electrolyte 21 of the electrolytic cell 2 and connected to the output terminal 31 of the power unit 3. The anode 5 is made of high-purity aluminum, and the number of the anodes 5 is multiple, and at least one anode 5 is installed in the electrolyte 21 of the electrolytic cell 2, and at least one anode 5 is not installed in the electrolyte 21 of the electrolytic cell 2 and is connected to the output terminal 32 of the power unit 3. The metal foil 7 is placed on the anode 5. The control unit 6 is connected to the power unit 3, controls the power unit 3, and adjusts the output voltage and output current supplied from the power unit 3 to control the chemical conversion process of the metal foil 7. Detailed features of the control unit 6 controlling the output voltage and output current supplied from the power unit 3 will be described later. The chemical conversion process of the metal foil 7 will be described below with reference to the drawings.

2A and 2B in addition to Fig. 1, Fig. 2A is a partially enlarged schematic diagram showing the structure of a corrosion pit formed on the metal foil of the chemical conversion system shown in Fig. 1, and Fig. 2B is a partially enlarged schematic diagram showing the structure of an oxide film formed on the metal foil of the chemical conversion system shown in Fig. 1. Figs. 2A and 2B show partial structures of the contact surface between the metal foil 7 of Fig. 1 and the electrolyte 21 in the electrolytic cell 2 in different cases. In the chemical conversion process of the metal foil 7, the power unit 3 continues to supply an output voltage and an output current to the metal foil 7, thereby causing an oxidation reaction on the surface of the metal foil 7 to form an oxide film 8 (as shown in Fig. 2B). Specifically, the chemical reactions occurring on the metal foil 7 at this time include electrolysis of water H ₂ O→O ^2- +2H ⁺ (this reaction is exothermic), ionization of Al metal Al→3e ^- +Al ³⁺ , and formation of aluminum oxide 2Al ³⁺ +3O ^2- →Al ₂ O ₃ +1670 kJ (this reaction is exothermic). At the same time, impurity borate ions in the electrolyte also undergo an oxidation reaction with aluminum ions to become BO ₃ ^3- +Al ³⁺ →AlBO ₃ , and the oxidation reaction of the impurity ions reduces the fracture resistance of the oxide film 8, and the quality of the oxide film 8 decreases. At the cathode 4, the reduction reaction of hydrogen 2H ⁺ +2e→H2 mainly occurs. Heat accumulates due to the water electrolysis and oxidation reaction of the metal foil 7, and the high temperature causes a side reaction of dissolving aluminum oxide; that is, the electrolyte 21 further corrodes the oxide film 8 formed on the metal foil 7, changing from Al2O3 + 6H ⁺ to ^2Al3 + + 3H2O, damaging the oxide layer.

The process of forming and dissolving the oxide film 8 will be further explained below in three stages. The first stage is to form a 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, during the first few seconds to 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 continuous thin layer without holes with a thickness of about 0.01 to 0.1 μm that can prevent the flow of current. In addition, since 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 electrolyte 21, the voltage at this stage increases rapidly from zero to a maximum value. The second stage is to form a porous layer of the oxide film 8. As the oxide film 8 is formed, the electrolyte 21 begins to dissolve the oxide film 8, but since the formation of the oxide film 8 is uneven, the thinnest part of the oxide film 8 dissolves first and holes are formed, and the electrolyte 21 continues to react chemically with the metal foil 7 through the holes, forming a porous layer on the oxide film 8. The third stage is to thicken the porous layer of the oxide film 8. As the non-porous layer continues to dissolve and a porous layer is formed, a new non-porous layer continues to grow, so that 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, the formation and dissolution of the oxide film 8 at the bottom of the hole do not stop, so the hole deepens, 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.

In the process of forming and dissolving the oxide film 8, if there is a defect in the oxide film 8, the aluminum electrolytic capacitor may have reliability problems. For example, the aluminum electrolytic capacitor repairs and thickens the oxide film 8 by the electrolyte during the load process, which increases the loss of the electrolyte, increases the viscosity, and increases the resistivity, resulting in an increase in the equivalent series resistance of the electrolyte and a significant increase in the loss of the aluminum electrolytic capacitor. In addition, the viscosity of the electrolyte increases and the metal foil 7 is uneven due to corrosion, making it difficult for the electrolyte to fully contact 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 the life of the aluminum electrolytic capacitor is shortened. In addition, gas is generated by electrolysis during the formation of the oxide film 8, and the gas also increases with the formation time, which is prone to expansion, leakage, or explosion of the aluminum electrolytic capacitor. Therefore, the quality of the oxide film 8 directly affects the performance of the aluminum electrolytic capacitor. Below, the parameters related to the quality of the oxide film 8 in the aluminum electrolytic capacitor and their characteristics are further described.

Referring to Figures 3A, 3B and 3C in addition to Figure 1, Figure 3A is a simplified structural schematic diagram of an aluminum electrolytic capacitor, Figure 3B is an equivalent circuit diagram of an aluminum electrolytic capacitor, and Figure 3C is a simplified equivalent circuit diagram of an aluminum electrolytic capacitor. As shown in Figures 3A and 3B, Ca in the diagrams 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 the dielectric loss and the 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, and 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, the cathode capacitance Cc and the equivalent capacitance Ce of the electrolyte can be ignored in FIG. 3C, and only the anode capacitance Ca is shown.

3C, the dielectric of the oxide film 8 has a great effect on blocking DC current, and since the dielectric of the oxide film 8 is impregnated with an electrolyte, when a DC voltage is applied, a small current is generated when the oxide film is reformed and repaired, which is called a leakage current. The more defects in the oxide film 8, the larger the leakage current, and the limited electrolyte in the aluminum electrolytic capacitor is consumed and depleted due to the repair reaction of the oxide film 8 caused by this. Refer to Figures 4A and 4B in conjunction with Figure 1, Figure 4A is a waveform diagram of the leakage current of the aluminum electrolytic capacitor, and Figure 4B is a waveform diagram of the output voltage and output current supplied from the power unit of the power supply device of the chemical conversion system shown in Figure 1. The solid line in Figure 4B shows the waveform diagram of the output current supplied from the power unit 3, and the dashed line shows the waveform diagram of the output voltage supplied from the power unit 3. As shown in Figure 4B, when the time during which the power unit 3 supplies 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 chemical conversion process of the metal foil 7 reaches a steady state. During the leakage current stage, where the current value is very small, defective areas on the metal foil 7 where the oxide film 8 is insufficient undergo dynamic dissolution and oxidation reactions until a new oxide film is formed.

Therefore, in order to avoid reliability problems in the formation and dissolution process of the oxide film 8 and improve the quality of the oxide film 8, the present invention will be further described below in which the quality of the oxide film 8 is improved by adjusting the output voltage or output current supplied from the power unit 3. Referring to FIG. 5A in conjunction with FIG. 1, FIG. 5A is a voltage/current waveform diagram of a first embodiment of the output voltage and output current supplied from the power unit of the power supply device of the chemical conversion 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, an increasing voltage pulse region V2, and a decreasing voltage pulse region V3. The constant voltage region V1, the increasing voltage pulse region V2, and the decreasing voltage pulse region V3 of the output voltage are constant, and the peak value of the increasing voltage pulse region V2 and the valley value of the decreasing voltage pulse region V3 respectively satisfy the following relational expressions.
Where:
is the voltage value of the constant voltage region V1, and the ripple coefficient of the constant voltage region V1 is ≦±2%,
is the peak value of the rising voltage pulse region V2,
is the valley value of the drop voltage pulse region V3,
is the voltage adjustment range coefficient preset in the control unit 6,
In this embodiment, the peak value of the rising voltage pulse region V2 is
The magnitude of the drop voltage pulse region V3 is the valley value
The size is different from that of the original.

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 a corresponding rising current, and at this time, the electric field strength on the oxide film 8 increases, which sufficiently destroys weak defect areas (e.g., impurity defects, crack defects, and the outermost hydrated aluminum oxide layer) in the oxide film 8 to promote dissolution, exposes the fresh aluminum substrate of the metal foil 7, shortens the dynamic repair time, and achieves energy saving effects. 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 a corresponding falling current, and at this time, the electric field strength on the oxide film 8 decreases, which prevents heat accumulation on the metal foil 7 and reduces the temperature of the metal foil 7, thereby suppressing the dissolution side reaction of the oxide film 8 and preventing the dissolution region from expanding, reducing damage to the oxide film 8, and weakening the oxidation reaction of impurity ions, thereby reducing the impurities in the oxide film 8. When the control unit 6 controls the output voltage of the power unit 3 so that it is in the constant voltage region V1, the output current of the power unit 3 also becomes a constant current state, and the oxide film 8 regenerates and fills the dissolved region, making the oxide film 8 denser and improving its quality.

As can be seen from the relational expression that the valley value of the voltage drop pulse region V3 must satisfy, the valley value of the voltage drop pulse region V3 must be greater than 0, which can ensure that the electrode polarity in the electrolytic cell 2 is not reversed, for example, that the cathode does not become the anode, and can avoid the metal material (such as stainless steel) of the cathode plate device corroding and dissolving due to polarity reversal, which can damage existing equipment and cause poor compatibility. In addition, when the lower limit of the voltage drop pulse region is greater than the amplitude "zero" and close to the amplitude "zero", a larger local voltage dip effect will be generated, which can more quickly complete the dissolution process of the defective parts and provide sufficient time for subsequent reoxidation and repair.

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 start point A1 of the pulse width time of the rising voltage pulse region V2 to the end point A2 of the pulse width time of the next adjacent falling voltage pulse region V3 is 1 to 100 seconds, that is, the frequency of the rising voltage pulse region V2 and the falling voltage pulse region V3 is 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 multiple rising voltage pulses, and the falling voltage pulse region V3 includes multiple falling voltage pulses. In some other embodiments, the rising voltage pulse region V2 and the next adjacent falling voltage pulse region V3 may be discontinuous, or may be a combination of multiple symmetrical or asymmetrical, adjacent or intermittent. In this case, the time from the start point A1 of the pulse width time of the rising voltage pulse region V2 to the end point A2 of the pulse width time of the next adjacent falling voltage pulse region V3 must also be 1 to 100 seconds. In some embodiments, the falling voltage pulse region V3 is located before the adjacent rising voltage pulse region V2, and in this case, the time from the start point of the pulse width time of the falling voltage pulse region V3 to the end point of the pulse width time of the next adjacent rising voltage pulse region V2 must also be 1 to 100 seconds.

5B in addition to FIG. 1 and FIG. 5A, FIG. 5B is a flow chart of a method for controlling the output voltage and output current supplied from the power unit of the power supply device of the chemical conversion system shown in FIG. 5A. First, step S1 is performed to prepare an electrolytic cell 2 containing an electrolytic solution 21, place an anode 5 and a cathode 4 in the electrolytic solution 21, and place a metal foil 7 on the anode 5. Next, step S2 is performed to connect the output terminals 31 and 32 of the power unit 3 to the anode 5 and the cathode 4, and the power unit 3 outputs an output voltage for chemical conversion of the metal foil 7. Thereafter, step S3 is performed to control the power unit 3 such that the output voltage has a constant voltage region V1, an increasing voltage pulse region V2, and a decreasing voltage pulse region V3, and the valley value of the decreasing voltage pulse region V3 satisfies the following relational expression:
, where:
is the voltage value in the constant voltage region V1,
is the valley value of the falling voltage pulse region V3.

6A in conjunction with FIG 1, which is a voltage and current waveform diagram of a second embodiment of the output voltage and output current supplied from the power unit of the power supply device of the chemical conversion 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, an increasing current pulse region I2, and a decreasing current pulse region I3. The constant current region I1, the increasing current pulse region I2, and the decreasing current pulse region I3 of the output current are constant, and the peak value of the increasing current pulse region I2 and the valley value of the decreasing current pulse region I3 respectively satisfy the following relational expressions.
Where:
is the current value of the constant current region I1, and the ripple coefficient of the constant current region I1 is ≦±2%,
is the peak value of the rising current pulse region I2,
is the valley value of the falling current pulse region I3,
is the current regulation range coefficient preset in the control unit 6,
In this embodiment, the peak value of the rising current pulse region I2 is
The magnitude of the falling current pulse region I3 is the valley value
The size is different from that of the original.

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 a corresponding rising voltage, and at this time, the electric field strength on the oxide film 8 increases, which sufficiently destroys weak defect areas (e.g., impurity defects, crack defects, and the outermost hydrated aluminum oxide layer) in the oxide film 8 to promote dissolution, exposes the fresh aluminum substrate of the metal foil 7, shortens the dynamic repair time, and achieves energy saving effects. 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 a corresponding falling voltage, and at this time, the electric field strength on the oxide film 8 decreases, which prevents heat accumulation on the metal foil 7 and reduces the temperature of the metal foil 7, thereby suppressing the dissolution side reaction of the oxide film 8 and preventing the dissolution region from expanding, reducing damage to the oxide film 8, and weakening the oxidation reaction of impurity ions, thereby reducing the impurities in the oxide film 8. When the control unit 6 controls the output current of the power unit 3 so that it is in the constant current region I1, the output voltage of the power unit 3 also becomes a constant voltage state, and the oxide film 8 regenerates and fills the dissolution region, making the oxide film 8 denser and improving its quality.

As can be seen from the relational expression that the valley value of the falling current pulse region I3 must satisfy, the valley value of the falling current pulse region I3 must be greater than 0, which can ensure that the electrode polarity in the electrolytic cell 2 is not reversed, for example, that the cathode does not become the anode, and can avoid that the metal material (such as stainless steel) of the cathode plate device is corroded and dissolved due to polarity reversal, which can damage existing equipment and cause poor compatibility. In addition, if the lower limit of the falling current pulse region I3 is greater than the amplitude "zero" and close to the amplitude "zero", a larger local current dip effect will be generated, which can more quickly complete the dissolution process of the defective parts and provide sufficient time for subsequent reoxidation and repair.

In addition, in order to ensure an 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. Still referring 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 frequency of the rising current pulse region I2 and the falling current pulse region I3 is 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 multiple rising current pulses, and the falling current pulse region I3 includes multiple falling current pulses. In some other embodiments, the rising current pulse region I2 and the next adjacent falling current pulse region I3 may be discontinuous, or may be a combination of multiple symmetrical or asymmetrical, 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 must also be between 1 and 100 seconds.

6B is a flow chart of a method for controlling the output voltage and output current supplied from the power unit of the power supply device of the chemical conversion system shown in FIG. 6A. First, step M1 is performed to prepare an electrolytic cell 2 containing an electrolytic solution 21, place an anode 5 and a cathode 4 in the electrolytic solution 21, and place a metal foil 7 on the anode 5. Next, step M2 is performed to connect the output terminals 31 and 32 of the power unit 3 to the anode 5 and the cathode 4, and the power unit 3 outputs an output current for chemical conversion of the metal foil 7. Thereafter, step M3 is performed to control the power unit 3 such that the output current has a constant current region I1, an increasing current pulse region I2, and a decreasing current pulse region I3, and the valley value of the decreasing current pulse region I3 satisfies the following relational expression:
, where:
is the current value in the constant current region I1,
is the valley value of the falling current pulse region I3.

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 not limited to being constant, and may be curved or stepped. By making the pulse region stepped, 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, a voltage/current waveform diagram of the third embodiment of the output voltage and output current supplied from the power unit of the power supply device of the chemical conversion 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 a corresponding rising current, and the rising voltage pulse region V2 of this embodiment is stepped, and each of the multiple steps (for example, the two steps shown in FIG. 7A) of the rising voltage pulse region V2 has a corresponding peak value, and the step with the highest peak value in the rising voltage pulse region V2 is
When the control unit 6 controls the output voltage of the power unit 3 to be in the voltage drop region V3, the output current of the power unit 3 becomes a corresponding current drop. The voltage drop region V3 in this embodiment is stepped, and each of the multiple steps (e.g., the two steps shown in FIG. 7A ) in the voltage drop region V3 has a corresponding valley value, and the step with the lowest valley value in the voltage drop region V3 is
It is.

7B is a voltage/current waveform diagram of the fourth embodiment of the output voltage and output current supplied from the power unit of the power supply device of the chemical conversion 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 a corresponding rising current, and the rising voltage pulse region V2 of this embodiment is stepped, and each of the multiple steps of the rising voltage pulse region V2 (for example, a single step shown in FIG. 7B) has a corresponding peak value, and the step with the highest peak value in the rising voltage pulse region V2 is
When the control unit 6 controls the output voltage of the power unit 3 to be in the voltage drop pulse region V3, the output current of the power unit 3 becomes the corresponding current drop, and the voltage drop pulse region V3 in this embodiment is intermittent, for example, the voltage drop pulse region V3 shown in FIG. 7B has two voltage drop pulses, and the voltages on both sides of each voltage drop pulse are equal to the voltages in the constant voltage region. The step with the lowest valley value in the voltage drop pulse region V3 is
and there is a constant voltage region between the two intermittent waveforms. Of course, in some embodiments, the control unit 6 can control the rising voltage pulse region V2 to be intermittent, that is, the rising voltage pulse region V2 includes multiple rising voltage pulses, and the voltages on both sides of each rising voltage pulse are equal to the voltage of the constant voltage region. The formation method is similar to the formation method of the falling voltage pulse region V3, so the description is omitted here. In some embodiments, the rising current pulse region includes multiple 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 multiple falling current pulses, and the currents on both sides of each falling current pulse are equal to the current of the constant current region.

7C is a voltage/current waveform diagram of the fifth embodiment of the output voltage and output current supplied from the power unit of the power supply device of the chemical conversion 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 a corresponding rising voltage, and the rising current pulse region I2 of this embodiment is stepped, and each of the multiple steps of the rising current pulse region I2 (for example, the two steps shown in FIG. 7C) has a corresponding peak value, and the step with the highest peak value in the rising current pulse region I2 is
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 a corresponding falling voltage. The falling current pulse region I3 in this embodiment is stepped, and each of the multiple steps (for example, the two steps shown in FIG. 7C ) in the falling current pulse region I3 has a corresponding valley value, and the step with the lowest valley value in the falling current pulse region I3 is
The multi-step or intermittent waveform can generate a dynamic process of multiple polarization, depolarization and repair, making the oxide film 8 denser and less defective, and shortening the formation time required for the subsequent repair process, i.e., reducing the power consumption per unit area.

In order 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, and the electric field is periodically changed by injecting ripples to avoid impurities in the metal foil 7 and improve the quality of the oxide film 8. Referring to Fig. 8A, a voltage waveform diagram of a sixth embodiment of the output voltage supplied from the power unit of the power supply device of the chemical conversion 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 greater than the peak value of the rising voltage pulse region V2.
The voltage in the drop voltage pulse region V3 includes high-frequency ripple components and low-frequency ripple components, and each high-frequency ripple component is smaller than the valley value of the drop voltage pulse region V3.
The frequency ripple component is greater than 50 Hz to 500 kHz, the frequency ripple component is in the range of 0.01 Hz to 1 Hz, and the dynamic repair of the oxide film 8 is promoted by utilizing the ripple stress.

Of course, in one embodiment, the voltage of the rising current pulse region I2 may include a high frequency ripple component, and/or the voltage of the falling current pulse region I3 may include a high frequency ripple component. Refer to Figure 8B, which is a current waveform diagram of a seventh embodiment of the output current provided by the power unit of the power supply device shown in Figure 1. As shown in the figure, the voltage of the rising current pulse region I2 of this embodiment includes a high frequency ripple component, and each high frequency ripple component has a peak value of the rising current pulse region I2.
The voltage of the falling current pulse region I3 includes high-frequency ripple components and low-frequency ripple components, and each high-frequency ripple component is smaller than the valley value of the falling current pulse region I3.
, the high frequency ripple component ranges from 50 Hz to 500 kHz, and the low frequency ripple component ranges from 0.01 Hz to 1 Hz. The high frequency ripple component here simulates the high frequency ripple stress of the actual circuit in which the electrolytic capacitor is placed, and utilizes the local hot spots caused by high frequency dielectric loss to accelerate the destruction and dissolution of the defective points, and then fills in the high frequency defective parts with the newly generated oxide film, promoting the dynamic repair of the oxide film 8. This can fundamentally improve the quality of the oxide film 8 and prevent the consumption of electrolyte caused by the dynamic repair of the electrolytic capacitor in applications with high frequency ripples.

As described above, the present invention provides a power supply device and a control method thereof. The control unit controls the output voltage output by the power unit to have an increasing voltage pulse region, a decreasing voltage pulse region, and a constant voltage region, or controls the output current output by the power unit to have an increasing current pulse region, a decreasing current pulse region, and a constant current region, respectively, thereby destroying the weak parts of the oxide film, delaying the dissolution and destruction process, and regenerating the metal foil to fill the dissolved parts, thereby improving the quality of the oxide film and further improving the capacity and life of the aluminum electrolytic capacitor. In addition, as can be seen from the relationship that the valley value of the decreasing voltage pulse region (or the decreasing current pulse region) should satisfy, the valley value of the decreasing voltage pulse region (or the decreasing current pulse region) must be greater than 0, which can ensure that the electrode polarity in the electrolytic cell is not reversed, and further avoid the corrosion and dissolution of the metal material constituting the cathode. In addition, 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, which generates a large local voltage and current dip effect to quickly complete the depolarization and dissolution process of the oxide film, shorten the dynamic repair time, and reduce the energy consumption of the entire power supply device.

Of course, the present invention may have various other embodiments without departing from the spirit and essence of the present invention, and those skilled in the art may make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should fall within the scope of protection of the claims of the present invention.

1: Power supply unit 2: Electrolytic cell 21: Electrolyte 3: Power unit 31, 32: Output terminal 4: Cathode 5: Anode 6: Control unit 7: Metal foil 8: Oxide film Ca: Anode capacitance Cc: Cathode capacitance Ce: Equivalent capacitance of electrolyte Rs: Equivalent conduction resistance Rdc1: Equivalent dielectric leakage current resistance Re: Equivalent resistance of electrolyte and electrolytic paper ESL: Equivalent inductance V1: Constant voltage region V2: Rising voltage pulse region V3: Falling voltage pulse region
：Peak value of rising voltage pulse region
: Valley value of voltage drop pulse region I1: Constant current region I2: Rising current pulse region I3: Falling current pulse region
：Peak value of rising current pulse region
: Valley value of falling current pulse region S1-S3, M1-M3: Process

Claims (28)

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: 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. The control method of claim 1, wherein the voltage in the rising voltage pulse region is constant, curved, or stepped, and/or the voltage in the falling voltage pulse region is constant, curved, or stepped. The control method according to claim 1, wherein the voltage in the rising voltage pulse region includes a high-frequency ripple component, and/or the voltage in 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. The control 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 rising voltage pulse region and the falling voltage pulse region are continuous. 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 . The control 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. 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: 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. The control method of claim 8, wherein the current in the rising current pulse region is constant, curved, or stepped, and/or the current in the falling current pulse region is constant, curved, or stepped. 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. The control method of claim 8, wherein the rising current pulse region includes one or more rising current pulses, 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 continuous. 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 . The control method of claim 8, wherein the rising current pulse region includes one or more rising current pulses, 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. 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: The chemical conversion system according to 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. The chemical conversion system of claim 15, wherein the voltage of the rising voltage pulse region is constant, curved, or stepped, and/or the voltage of the falling voltage pulse region is constant, curved, or stepped. The chemical conversion system of claim 15, wherein the voltage in the rising voltage pulse region includes a high-frequency ripple component, and/or the voltage in 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. The chemical conversion system of claim 15, 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 rising voltage pulse region and the falling voltage pulse region are contiguous. 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, The chemical conversion system of claim 15, 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. 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: The chemical conversion system according to claim 22, 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. The chemical conversion system of claim 22, wherein the current in the rising current pulse region is constant, curved, or stepped, and/or the current in the falling current pulse region is constant, curved, or stepped. 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. The chemical conversion system of claim 22, wherein the rising current pulse region includes one or more rising current pulses, 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. 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: The chemical conversion system of claim 22, wherein the rising current pulse region includes one or more rising current pulses, 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.