TWI554019B - Inverting apparatus and control method thereof - Google Patents

Description

Inverter device and control method thereof

The present invention relates to a power conversion technique, and more particularly to an inverter device and a control method thereof.

In order to reduce the consumption rate of petrochemical energy, today's power systems are actively developing the application of renewable energy. For example, a photovoltaic module that generates electricity by solar energy, a wind power module that generates power by wind energy, a hydropower module that generates power by water flow, or other types of renewable energy power generation modules. However, since the above-mentioned regenerative power generation modules use natural resources for power generation, their output power characteristics/output capabilities are significantly affected by the environment.

For example, a DC power generating device that generates electricity from a photovoltaic module (such as a solar panel), for example, weather conditions, solar panels being shielded, and other possible external conditions may cause DC generated by the photovoltaic module. The power characteristics/output capabilities of the power supply vary.

DC power generation device composed of such a renewable energy power generation module Most of them have the problem of unstable output capability. Therefore, when such a DC power generating device is applied to an AC power supply system, the rear-end inverter device needs to be designed to adjust to this problem. Otherwise, if the inverter device at the back end cannot respond to the power characteristic change of the DC power generating device at the front end in time, for example, if the input voltage and the command voltage are too different, the input voltage of the inverter device may not be able to follow the excessive command. Voltage causes a problem with system failure.

The present invention provides an inverter device and a control method thereof, which can prevent the problem that the inverter device cannot react in time to cause a system failure when the output capability of the front-end DC power source generating device suddenly changes.

The inverter device of the present invention includes an inverter circuit, a detection circuit, and a control circuit. The inverter circuit receives a DC input power source for converting the DC input power source into an AC output power source. The detection circuit is configured to detect an input voltage and an input current of the DC input power source. The control circuit is coupled to the inverter circuit and the detection circuit for providing a control signal to control the inverter circuit, so as to adjust the voltage value of the input voltage to the command voltage represented by the control signal. The control circuit calculates the voltage difference between the detected input voltage and the command voltage, and determines whether the voltage difference is greater than a preset value. When the control circuit determines that the voltage difference is greater than the preset value, the voltage value of the set command voltage is equal to the voltage value of the current input voltage.

In an embodiment of the invention, the control circuit includes a maximum power point tracking (MPPT) module, an adder, and a drive Dynamic circuit. The maximum power point tracking operation module is configured to sample the input voltage and the input current, calculate the voltage difference to determine whether the voltage difference is greater than the preset value, and generate a disturbance signal accordingly. The adder is coupled to the maximum power point tracking operation module, and receives the disturbance signal and the reference signal and generates a command voltage, wherein the command voltage is the disturbance amount represented by the disturbance signal and the command voltage of the previous time point represented by the reference signal. The superposition of voltage values. The drive circuit receives the command voltage and generates a control signal accordingly.

In an embodiment of the invention, when the MPPT operation module determines that the voltage difference is less than or equal to a preset value, the MPPT operation module adjusts the disturbance signal based on the maximum power point tracking operation.

In an embodiment of the present invention, when performing the maximum power point tracking operation, the MPPT operation module calculates the input power according to the input voltage and the input current, and when the control circuit determines that the voltage difference is less than or equal to the preset value, the MPPT operation module borrows The disturbance amount is modulated by comparing the input power before and after the disturbance to generate a corresponding disturbance signal to bring the input power closer to the maximum input power.

In an embodiment of the invention, if the input power at the current time point is greater than the input power at the previous time point, the MPPT operation module provides the same disturbance amount as the disturbance direction at the previous time point, and if the current time point is input. The power is less than or equal to the input power of the previous time point, and the MPPT operation module provides the disturbance amount opposite to the disturbance direction at the previous time point.

The control method of the inverter device of the present invention is suitable for tracking the maximum input power of the DC input power received by the inverter device. The control method includes the following steps Step: detecting the input voltage and input current of the DC input power; providing a control signal to control the input voltage, thereby adjusting the voltage value of the input voltage to the command voltage represented by the control signal; calculating the detected input voltage and the command voltage a voltage difference value; determining whether the voltage difference is greater than a preset value; and when the voltage difference is greater than a preset value, setting a voltage value of the command voltage equal to a voltage value of the current input voltage.

In an embodiment of the invention, the control signal is provided to control the input voltage, and the step of adjusting the voltage value of the input voltage to the command voltage represented by the control signal comprises: providing a disturbance signal representing the disturbance amount; and superimposing the disturbance signal to the reference signal And generating a command voltage, wherein the command voltage is a superposition of a disturbance amount represented by the disturbance signal and a voltage value of the command voltage represented by the reference signal at a previous time point; and generating a control signal according to the command voltage.

In an embodiment of the invention, the control method of the inverter device further includes the following steps: adjusting the disturbance signal based on the maximum power point tracking operation when the voltage difference is less than or equal to the preset value.

In an embodiment of the invention, the step of adjusting the disturbance signal based on the maximum power point tracking operation includes: calculating the input power according to the input voltage and the input current; comparing the input power before and after the disturbance; and adjusting the disturbance amount according to the comparison result, thereby generating Corresponding to the disturbance signal, the input power is approached to the maximum input power.

In an embodiment of the present invention, the step of adjusting the disturbance amount according to the comparison result, so that the input power approaches the maximum input power includes: determining whether the input power at the current time point is greater than the input power of the previous time point; The input power of the point is greater than the input power of the previous time point, providing the disturbance side at the previous time point. To the same amount of disturbance; and if the input power at the current time point is less than or equal to the input power at the previous point in time, the amount of disturbance opposite to the direction of the disturbance at the previous point in time is provided.

Based on the above, an embodiment of the present invention provides an inverter device and a control method thereof, which can determine a DC input by calculating a voltage difference between an input voltage and a command voltage, and comparing whether the voltage difference exceeds a preset value. Whether the power characteristics of the power supply are offset. Wherein, the control method of the present case sets the command voltage to the current input voltage when determining that the power characteristic of the DC input power source is shifted, and then performs the maximum power point tracking operation based on the set value of the command voltage, thereby preventing the input. The voltage cannot follow the excessive command voltage and cause a system failure.

The above described features and advantages of the invention will be apparent from the following description.

100‧‧‧Inverter

110‧‧‧Inverter circuit

120‧‧‧Detection circuit

130‧‧‧Control circuit

131‧‧‧MPPT computing module

132‧‧‧Adder

133‧‧‧ drive circuit

ACout‧‧‧AC output power supply

CV1, CV2‧‧‧ characteristic curve

DCin‧‧‧DC input power supply

DCG‧‧‧DC power generation device

EG‧‧‧ grid

I1, I1', I1", I1'''‧‧‧ current value

Iout‧‧‧Output current

Iin‧‧‧ input current

S410~S470‧‧‧Steps

Sc‧‧‧ control signal

Sc’‧‧‧ reference signal

Sd‧‧‧ disturbance signal

T0, t1, t2‧‧‧ time points

V1, V1', V1", V1''', V2, Vp‧‧‧ voltage values

Vcmd, Vcmd’‧‧‧ command voltage

Vout‧‧‧ output voltage

Vin‧‧‧Input voltage

Vth‧‧‧ default value

△V‧‧‧ disturbance

FIG. 1 is a schematic diagram of an inverter device according to an embodiment of the present invention.

2 is a schematic diagram of a control circuit in accordance with an embodiment of the present invention.

3 is a schematic diagram showing a voltage-current relationship of a DC input power supply according to an embodiment of the present invention.

4 is a schematic diagram showing the time-voltage relationship of a DC input power supply according to an embodiment of the present invention.

FIG. 5 is a flow chart showing the steps of a method for controlling an inverter device according to an embodiment of the present invention.

In order to make the disclosure of the present disclosure easier to understand, the following specific embodiments are examples of the disclosure that can be implemented. In addition, wherever possible, the same elements, components, and steps in the drawings and embodiments are used to represent the same or similar components.

FIG. 1 is a schematic diagram of an inverter device according to an embodiment of the present invention. Referring to FIG. 1, the inverter device 100 of the present embodiment is adapted to be applied in an AC power supply system. In the AC power system, the inverter device 100 can receive a DC input power source DCin (including a DC input voltage Vin and an input current Iin) from a DC power generating device DCG at the front end, and generate an AC output power ACout (including The AC output voltage Vout and the output current Iout are supplied to the grid EG at the back end. The DC power generating device DCG can be, for example, a photovoltaic module, a wind power module, a hydropower module, or other types of renewable energy power generation modules, and the invention is not limited thereto.

In the embodiment, the inverter device 100 includes an inverter circuit 110, a detection circuit 120, and a control circuit 130. The inverter circuit receives the DC input power source DCin and is used to convert the DC input power source into an AC output power source ACout. The circuit configuration of the inverter circuit 110 can be, for example, a half bridge asymmetric, a half bridge symmetric, a full bridge or other feasible inverter circuit configuration, which is not limited by the present invention.

The detecting circuit 120 is coupled to the input end of the inverter circuit 110 to detect the input voltage Vin of the DC input power source DCin and the input current Iin, and the detected The information of the input voltage Vin and the input current Iin is output to the control circuit 130 as a basis for control.

The control circuit 130 is coupled to the inverter circuit 110 and the detection side circuit 120. The control circuit 130 is configured to control the power conversion of the inverter circuit 110 and the input voltage Vin of the DC input power source DCin, so that the utilization rate of the front-end DC power generation device DCG is maintained to a certain extent. For example, the control circuit 130 can generate a control signal Sc to control the DC-to-AC conversion of the inverter circuit 110. The control signal Sc can be, for example, a pulse width modulation signal for controlling the switching period of the inverter circuit 110. (PWM signal), but the invention is not limited thereto. On the other hand, the control circuit 130 can also provide a disturbance signal Sd to disturb the voltage value of the input voltage Vin, thereby implementing a maximum power point tracking (MPPT) control mechanism, so that the front end DC power generation device DCG The output power can approach the maximum power within the specification.

Specifically, the inverter circuit 110 of the embodiment adjusts the voltage value of the input voltage Vin to the command voltage Vcmd represented by the control signal Sc according to the received control signal Sc. For example, if the current input voltage Vin is 5V, and the control circuit 130 determines that the input voltage Vin having the maximum output power of the front-end DC power generating device DCG is 3V, then the control circuit 130 provides a corresponding The control signal Sc having the command voltage Vcmd of 3V is supplied to the inverter circuit 110, so that the inverter circuit 110 reacts to the control signal Sc to gradually reduce the input voltage Vin from 5V to 3V.

In this embodiment, the control circuit 130 basically controls the MPPT. The mechanism is configured to set the command voltage Vcmd, and accordingly generate a corresponding control signal Sc to control the DC input power source DCin, so that the output power of the front-end DC power generating device DCG can approach the maximum power point. However, when the difference between the input voltage Vin and the set command voltage Vcmd is too large, the control circuit 130 adjusts the set value of the command voltage Vcmd to prevent the actual input voltage Vin from following the excessive command voltage Vcmd and causing the system to lose control.

In detail, the power characteristics/output capability of the front-end DC power generating device DCG is not maintained at a fixed value, and the power characteristics may be changed at any time due to changes in some external conditions. For example, if the front-end DC power generating device DCG is a photovoltaic module composed of solar panels, the power characteristics/output capability of the solar panel is greatly affected by the weather. If the solar panel is shielded, the input current Iin will suddenly drop and the power characteristics will change. At this time, if the control circuit 130 continues the control signal SC to control the inverter circuit 110 by continuing the set value of the command voltage Vcmd in the previous period, the inverter circuit 110 may not continue to operate.

In order to solve the above problem, the control circuit 130 of the present embodiment calculates the voltage difference between the detected input voltage Vin and the command voltage Vcmd as a basis for determining the command voltage Vcmd. The control circuit 130 determines whether the voltage difference between the input voltage Vin and the command voltage Vcmd is greater than a preset value. When the control circuit 130 determines that the calculated voltage difference is less than or equal to the preset value, the power characteristic of the DC power generating device DCG indicating the front end does not shift too much, so the control circuit 130 adjusts the command voltage based on the MPPT operation. Vcmd, and set the input voltage Vin To follow the voltage value of the command voltage Vcmd, so that the DC input power DCin can have the maximum power. On the contrary, when the control circuit 130 determines that the voltage difference is greater than the preset value, it indicates that the DC power generating device DCG may shift the power characteristic curve due to the change of the external condition, so the control circuit 130 sets the voltage value of the command voltage Vcmd at this time. It is equal to the voltage value of the current input voltage Vin. In other words, in a case where the voltage difference between the input voltage Vin and the command voltage Vcmd exceeds a preset value, the control circuit 130 sets the voltage value of the command voltage Vcmd to follow the current input voltage Vin, and then sets the command voltage Vcmd. The MPPT operation is performed on the basis to prevent the input voltage Vin from failing to follow the excessive command voltage Vcmd and causing a system failure.

The specific system architecture of the control circuit 130 is shown in FIG. 2. Referring to FIG. 2, the control circuit 130 includes an MPPT operation module 131 (ie, a maximum power point tracking operation module), an adder 132, and a drive circuit 133.

In this embodiment, the MPPT operation module 131 samples the input voltage Vin and the input current Iin, calculates the voltage difference between the input voltage Vin and the command voltage Vcmd to determine whether the voltage difference is greater than a preset value, and generates Disturbance signal Sd. When the MPPT calculation module 131 determines that the voltage difference is less than or equal to a preset value, the MPPT operation module 131 adjusts the disturbance signal Sd based on the MPPT operation. When the MPPT operation module 131 determines that the voltage difference is greater than or equal to the preset value, the MPPT module does not perform the MPPT operation, and the control circuit 130 sets the voltage value of the command voltage Vcmd to follow the current input voltage Vin, that is, the setting. The voltage value of the command voltage is equal to the current voltage value of the input voltage.

In the MPPT operation, the MPPT operation module 131 of the control circuit 130 The input power is calculated according to the input voltage Vin and the input current Iin, and the disturbance amount ΔV is modulated by comparing the input power before and after the disturbance to generate a corresponding disturbance signal Sd. For example, if the input power at the current time point is greater than the input power at the previous time point, the disturbance signal Sd provided by the MPPT calculation module 131 is the same disturbance amount ΔV as the disturbance direction at the previous time point (to The disturbance amount + ΔV indicates), and if the input power at the current time point is less than or equal to the input power of the previous time point, the disturbance signal Sd provided by the MPPT calculation module 131 is opposite to the disturbance direction at the previous time point. The disturbance amount ΔV (represented by the negative disturbance amount - ΔV).

Then, the disturbance signal Sd is superimposed with a reference signal Sc' by the adder 132, thereby generating a corresponding command voltage Vcmd to be supplied to the driving circuit 133. In other words, the command voltage Vcmd generated by the adder 132 is a superposition of the disturbance amount ΔV represented by the disturbance signal Sd and the voltage value represented by the reference signal Sc'. In the present embodiment, the voltage value represented by the reference signal Sc' is the command voltage Vcmd' at the previous point in time. Therefore, the command voltage Vcmd generated by the adder 132 is actually equal to the superposition of the disturbance amount ΔV and the command voltage Vcmd' at the previous point in time, that is, Vcmd = Vcmd' + ΔV or Vcmd = Vcmd' - ΔV. Thereby, the driving circuit 133 generates the corresponding control signal Sc based on the set command voltage Vcmd to control the operation of the inverter circuit 110. The driving circuit 133 of the embodiment further includes a pulse width modulation generating circuit, and the control signal Sc generated is a PWM signal for controlling the switching period of the inverter circuit 110.

For example, as seen in conjunction with FIG. 3, it is assumed that the input voltage Vin at the current time point is the voltage value V1' and the input voltage Vin at the previous time point is the voltage value V1". The control circuit provides a disturbance amount ΔV of the negative disturbance direction (i.e., the voltage is lowered) between the time points. At this time, the control circuit 130 calculates the input power P1' at the current time point as V1'×I1' according to the input voltage Vin and the input current Iin, and the input power P1" at the previous time point is V1"×I1". The control circuit 130 determines that the current input power P1' is greater than the input power P1" of the previous time point according to the result of the power calculation, and therefore continues to provide the same disturbance amount ΔV as the previous time point of the disturbance direction, that is, let V1'= V1"-?V causes the input voltage Vin to approach the voltage value V1 having the maximum input power P1.

On the other hand, if the input voltage Vin at the current time point is the voltage value V1''' and the input voltage Vin at the previous time point is the voltage value V1. The control circuit 130 provides a disturbance amount ΔV in the negative disturbance direction between the time points. In this case, since the control circuit 130 calculates the input power P1''' (equal to V1'''×I1''') at the current time point according to the input voltage Vin and the input current Iin, the input power is less than the previous time point. P1, therefore, the control circuit 130 will instead provide the disturbance amount ΔV of the positive disturbance direction (ie, the voltage is raised), that is, let V1'''=V1+ΔV, so that the input voltage Vin is directed to the voltage value having the maximum input power P1. V1 approaches.

The specific control flow of the inverter device 100 of the embodiment of the present invention will be described below with reference to FIG. 3 and FIG. 4. 3 is a diagram showing the relationship between the input voltage Vin and the input current Iin of the DC power generating device DCG under different external conditions. Figure 4 shows the relationship between the DC input power DCin time and the input voltage Vin.

Referring to FIG. 3 and FIG. 4 together, in the present embodiment, the power characteristic available characteristic curve of the DC power generating device DCG during the period from time t0 to time t1. CV1 indicates. During this period, the control circuit 130 first sets the voltage value V1 that meets the maximum power point of the characteristic curve CV1 as the set value of the current command voltage Vcmd.

Specifically, in the period t0 to t1, since the power characteristics of the DC power generating device DCG have not changed, the control circuit 130 determines the voltage difference between the command voltage Vcmd and the input voltage Vin (ie, |V1-Vin |) is less than the preset value. The control circuit 130 performs an MPPT operation at this time, thereby generating a corresponding control signal Sc based on the set voltage value V1 to control the operation of the inverter circuit 110. The control circuit 130 increases or decreases a disturbance amount in response to the disturbance signal Sd to increase or decrease the magnitude of the voltage value of the input voltage Vin, thereby adjusting the voltage value of the input voltage Vin to the voltage value V1 of the command voltage Vcmd.

From a time point of view, as shown by the waveform of the input voltage Vin in the period t0 to t1 of FIG. 4, the input voltage Vin is reflected in the variation of the disturbance amount ΔV in the interval of the voltage value V1 approaching the command voltage Vcmd. And it oscillates back and forth around the voltage value V1, thereby dynamically stabilizing the voltage value V1.

Then, during the period from time t1 to time t2, the power characteristic of the DC power source generating device DCG changes from the characteristic curve CV1 to the characteristic curve CV2 in response to a change in external conditions. At this time, since the voltage difference between the input voltage Vin and the command voltage Vcmd has not exceeded the preset value Vth, the control circuit 130 cannot judge that the external condition has changed, so the control circuit 130 will still command the voltage during the period t1 to t2. Vcmd is set to a voltage value of V1. Therefore, during this period, since the input voltage Vin is smaller than the command voltage Vcmd, the inverter circuit 110 stops switching.

At time t2, the voltage of the input voltage Vin and the command voltage Vcmd The difference reaches the preset value Vth. At this time, the control circuit 130 determines that the change of the external condition has caused the power characteristic curve of the DC power generating device DCG to shift according to the voltage difference. The control circuit 130 changes the command voltage Vcmd from the voltage value V1 to the voltage value V2 at the time point t2. Therefore, during this period, the inverter circuit 110 reacts to the control signal Sc to re-oscillate the input voltage Vin to the vicinity of the voltage value V2.

Thereafter, the control circuit 130 adjusts the command voltage Vcmd and the input voltage Vin in a manner similar to the MPPT control described above, so that the command voltage Vcmd and the input voltage Vin can be stabilized at a maximum power point of the characteristic curve CV2 after a period of time. Voltage value Vp.

FIG. 5 is a flow chart showing the steps of a method for controlling an inverter device according to an embodiment of the present invention. The control method of the inverter device of the present embodiment can be applied to the inverter device 100 illustrated in the embodiment of FIG. 1, but the present invention is not limited thereto. In the control method of the embodiment, first, the DC input power source DCin is received by the inverter circuit (such as 110) (step S410), and the input voltage Vin and the input of the DC input power source DCin are detected by the detecting circuit (such as 120). Current Iin (step S420). Next, the control signal Sc is provided by the control circuit (eg, 130) to control the input voltage Vin, thereby adjusting the voltage value of the input voltage Vin to the command voltage Vcmd represented by the control signal Sc (step S430). Thereafter, the control circuit calculates a voltage difference between the detected input voltage Vin and the command voltage Vcmd (step S440), and determines whether the voltage difference is greater than a preset value (step S450).

If the determination in step S450 is YES, the control circuit sets the voltage value of the command voltage Vcmd to be equal to the voltage value of the current input voltage Vin (step S460). on the contrary, If the determination in step S450 is no, the control circuit adjusts the generated disturbance signal Sd based on the MPPT operation (step S470), so that the input power of the direct current input power source DCin can be substantially maintained near the maximum power point.

The control method described in the embodiment of FIG. 4 can obtain sufficient support and teaching according to the foregoing description of FIG. 1 to FIG. 3, and thus similarities or repetitions are not described herein again.

In summary, the embodiment of the present invention provides an inverter device and a control method thereof, which can calculate a voltage difference between an input voltage and a command voltage, and compare whether the voltage difference exceeds a preset value. Determine whether the power characteristics of the DC input power supply are offset. Wherein, the control method of the present case sets the command voltage to the current input voltage when determining that the power characteristic of the DC input power source is shifted, and then performs the maximum power point tracking operation based on the set value of the command voltage, thereby preventing the input. The voltage cannot follow the excessive command voltage and cause a system failure.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧Inverter

110‧‧‧Inverter circuit

120‧‧‧Detection circuit

130‧‧‧Control circuit

ACout‧‧‧AC output power supply

DCin‧‧‧DC input power supply

DCG‧‧‧DC power generation device

EG‧‧‧ grid

Iout‧‧‧Output current

Iin‧‧‧ input current

Sc‧‧‧ control signal

Sd‧‧‧ disturbance signal

Vcmd‧‧‧ command voltage

Vout‧‧‧ output voltage

Vin‧‧‧Input voltage

△V‧‧‧ disturbance

Claims (10)

An inverter device includes: an inverter circuit for receiving a DC input power source for converting the DC input power source into an AC output power source; and a detecting circuit for detecting an input voltage of the DC input power source An input circuit coupled to the inverter circuit and the detection circuit for providing a control signal for controlling the inverter circuit, thereby adjusting a voltage value of the input voltage to represent the control signal a command voltage, wherein the control circuit calculates a voltage difference between the detected input voltage and the command voltage, and determines whether the voltage difference is greater than a predetermined value, when the control circuit determines that the voltage difference is greater than the When the preset value is set, the voltage value of the command voltage is set to be equal to the current voltage value of the input voltage. The inverter device of claim 1, wherein the control circuit comprises: a maximum power point tracking operation module for sampling the input voltage and the input current, and calculating the voltage difference to determine the voltage difference. Whether the value is greater than the preset value, and a disturbance signal is generated; an adder coupled to the maximum power point tracking operation module, receiving the disturbance signal and a reference signal and generating the command voltage, wherein the command The voltage is a superposition of a disturbance amount represented by the disturbance signal and a voltage value of a command voltage at a previous time point represented by the reference signal; A driving circuit receives the command voltage and generates the control signal accordingly. The inverter device of claim 2, wherein the maximum power point tracking operation module is based on a maximum power point when the maximum power point tracking operation module determines that the voltage difference is less than or equal to the preset value. Tracking operations to adjust the disturbance signal. The inverter device of claim 3, wherein the maximum power point tracking operation module calculates an input power according to the input voltage and the input current when the maximum power point tracking operation is performed, when the control circuit When the voltage difference is determined to be less than or equal to the preset value, the maximum power point tracking operation module modulates the disturbance amount by comparing the input power before and after the disturbance, so as to generate a corresponding disturbance signal, so that the input power approaches At a maximum input power. The inverter device of claim 4, wherein if the input power at the current time point is greater than the input power at the previous time point, the maximum power point tracking operation module provides a disturbance direction from the previous time point. The same amount of disturbance, and if the input power at the current time point is less than or equal to the input power of the previous time point, the maximum power point tracking operation module provides a disturbance amount opposite to the disturbance direction at the previous time point. A control method for an inverter device is adapted to track a maximum input power of a DC input power received by the inverter device, the control method comprising: detecting an input voltage and an input current of the DC input power; providing a Controlling the signal to control the input voltage, thereby adjusting the voltage value of the input voltage to a command voltage represented by the control signal; Calculating a voltage difference between the detected input voltage and the command voltage; determining whether the voltage difference is greater than a preset value; and when the voltage difference is greater than the preset value, setting a voltage value of the command voltage equal to The current voltage value of the input voltage. The control method of the inverter device according to claim 6, wherein the step of providing the control signal to control the input voltage, thereby adjusting the voltage value of the input voltage to the command voltage represented by the control signal comprises: Providing a disturbance signal representing a disturbance amount; superimposing the disturbance signal to a reference signal to generate the command voltage, wherein the command voltage is the disturbance amount represented by the disturbance signal and one of the reference signals The superposition of the voltage value of the command voltage at the time point; and generating the control signal according to the command voltage. The control method of the inverter device according to claim 7, further comprising: adjusting the disturbance signal based on a maximum power point tracking operation when the voltage difference is less than or equal to the preset value. The method for controlling an inverter device according to claim 8, wherein the step of adjusting the disturbance signal based on the maximum power point tracking operation comprises: calculating an input power according to the input voltage and the input current; comparing before and after the disturbance Input power; and modulating the disturbance amount according to a comparison result, thereby generating a corresponding disturbance signal to bring the input power closer to a maximum input power. The control method of the inverter device according to claim 9, wherein the step of adjusting the disturbance amount according to the comparison result, wherein the step of bringing the input power closer to the maximum input power comprises: determining an input of a current time point Whether the power is greater than the input power of the previous time point; if the input power at the current time point is greater than the input power of the previous time point, providing the same disturbance amount as the previous disturbance direction at the previous time point; and if the current time point is input The power is less than or equal to the input power of the previous time point, providing a disturbance amount opposite to the disturbance direction at the previous time point.