TWI548195B - Inverting apparatus and alternating current power system using the same - Google Patents

Description

Inverter device and AC power system using same

The present invention relates to a power conversion technology, and more particularly to an inverter device and an AC power supply system using the same.

Generally used in an inverter device of an AC power system (such as a photovoltaic grid-connected system, a wind-powered grid-connected system, an uninterruptible power system, or a large-scale backup power system), usually only provides effective power output, and cannot provide compensation for invalid power output at the same time. . Therefore, when the reactive power generated by the inverter device rises, the AC output voltage rises and the inverter device is easily broken. As a result, the DC input power cannot be effectively converted into AC power for power supply, thereby wasting power.

In the prior art, the inverter device sets a sampling circuit for the AC output voltage to detect whether the AC output voltage is abnormal. However, in the current inverter device, after sampling the voltage value of the AC output voltage, the sampling circuit must be output to the microprocessor in the inverter device for complicated operation, and the microprocessor can determine the AC output voltage. Whether there is an overpressure or undervoltage condition. In other words, the microprocessor cannot immediately detect an abnormality in the AC output voltage. In addition, due to the general sampling The circuit design is too complicated, which will result in an increase in the cost of the overall circuit design of the inverter device.

The invention provides an inverter device and an AC power supply system using the same, which can realize detection and protection of an AC output voltage by a simple circuit configuration.

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 voltage for converting the DC input voltage to an AC output voltage. The detecting circuit is coupled to the inverter circuit and is configured to sample the AC output voltage, wherein the detecting circuit compares the first reference voltage and the second reference voltage with the sampled AC output voltage, respectively, to generate the first indication signal and the second Indication signal. The control circuit is coupled to the inverter circuit and the detection circuit for controlling the operation of the inverter circuit. The control circuit determines whether the amplitude of the AC output voltage is at the working voltage according to the first indication signal and the second indication signal in each driving cycle. The interval, and depending on the result of the judgment, determines whether over voltage protection or under voltage protection is enabled to control the power conversion of the inverter circuit.

In an embodiment of the invention, when the control circuit determines that the amplitude of the AC output voltage is greater than the first reference voltage and the second reference voltage according to the first indication signal and the second indication signal, the control circuit enables overvoltage protection to control the inverter. The power conversion of the circuit, and when the control circuit determines that the amplitude of the AC output voltage is less than the first reference voltage and the second reference voltage according to the first indication signal and the second indication signal, the control circuit enables the undervoltage protection to control the inverter circuit. Power conversion.

In an embodiment of the invention, the detection circuit includes an amplitude adjustment unit, a reference voltage generation unit, a first comparison unit, and a second comparison unit. The amplitude adjustment unit receives the AC output voltage and adjusts the amplitude of the AC output voltage according to the gain adjustment ratio, thereby generating a sampling voltage associated with the AC output voltage. The reference voltage generating unit is configured to generate the first reference voltage and the second reference voltage. The first input end of the first comparison unit is coupled to the amplitude adjustment unit to receive the sampling voltage, the second input end of the first comparison unit is coupled to the reference voltage generation unit to receive the first reference voltage, and the output end of the first comparison unit is output The first indication signal. The first input end of the second comparison unit is coupled to the amplitude adjustment unit to receive the sampling voltage, the second input end of the second comparison unit is coupled to the reference voltage generation unit to receive the second reference voltage, and the output end of the second comparison unit is output The second indication signal.

In an embodiment of the invention, the control circuit includes an AC voltage protection unit, a high voltage detection unit, a low voltage detection unit, and a drive controller. The AC voltage protection unit is configured to generate an overvoltage protection signal and an undervoltage protection signal according to the first indication signal and the second indication signal. The high voltage detecting unit is coupled to the AC voltage protection unit and receives the first indication signal, wherein the high voltage detecting unit determines whether to provide the first indication signal to the AC voltage protection unit according to the sampling control signal. The low voltage detecting unit is coupled to the AC voltage protection unit and receives the second indication signal, wherein the low voltage detecting unit determines whether to provide the second indication signal to the AC voltage protection unit according to the sampling control signal. The driving controller is coupled to the inverter circuit and the AC voltage protection unit for generating a driving control signal to control the operation of the inverter circuit, wherein the driving controller adjusts the control signal according to the overvoltage protection signal, thereby performing overvoltage protection, and Pressure protection The number adjusts the control signal to perform undervoltage protection.

In an embodiment of the invention, the control circuit further includes an enabling unit. The enabling unit is coupled to the high voltage detecting unit and the low voltage detecting unit, and is configured to generate a sampling control signal, wherein the enabling unit generates an enabled sampling control signal during a preset period of each driving cycle, thereby enabling the high voltage detecting unit and the low voltage detecting The unit responds to the enabled sampling control signal to provide the first indication signal and the second indication signal to the AC voltage protection unit.

The AC power supply system of the present invention includes a DC power source generating device and an inverter device. A DC power generating device is used to generate a DC input voltage. The inverter device is coupled to the DC power generating device, wherein the inverter device includes an inverter circuit, a detecting circuit, and a control circuit. The inverter circuit receives a DC input voltage for converting the DC input voltage to an AC output voltage. The detecting circuit is coupled to the inverter circuit and is configured to sample the AC output voltage, wherein the detecting circuit compares the first reference voltage and the second reference voltage with the sampled AC output voltage, respectively, to generate the first indication signal and the second Indication signal. The control circuit is coupled to the inverter circuit and the detection circuit for controlling the operation of the inverter circuit. The control circuit determines whether the amplitude of the AC output voltage is at the working voltage according to the first indication signal and the second indication signal in each driving cycle. The interval, and depending on the result of the judgment, determines whether overvoltage protection or undervoltage protection is enabled to control the power conversion of the inverter circuit.

Based on the above, an embodiment of the present invention provides an inverter device and an AC power supply system using the same. The inverter device can generate a plurality of indication signals according to the comparison result by comparing the amplitude of the AC output voltage with the reference voltage, and then generating the The logical combination of the indication signals determines whether the current AC output voltage has an overvoltage or undervoltage condition. Therefore, the inverter device of the embodiment of the present invention does not need to perform complicated calculations, and can quickly determine the AC output. Whether the voltage is abnormal. In addition, the indication signal indicating the amplitude of the AC output voltage can be realized by a relatively simple circuit architecture composed of comparators, and thus does not impose an additional burden on the overall circuit design cost.

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

10‧‧‧AC power system

50‧‧‧DC power generation device

100‧‧‧Inverter

110‧‧‧Inverter circuit

120‧‧‧Detection circuit

122‧‧‧Amplitude adjustment unit

124‧‧‧reference voltage generating unit

126‧‧‧ first comparison unit

128‧‧‧Second comparison unit

130‧‧‧Control circuit

131‧‧‧AC voltage protection unit

132‧‧‧High voltage detection unit

133‧‧‧Low-voltage detection unit

134‧‧‧ drive controller

135‧‧‧Enable unit

EG‧‧‧ grid

GND‧‧‧ ground terminal

GR‧‧‧ Gain adjustment ratio

N1, N2‧‧‧ nodes

PVm‧‧‧PV modules

R1, R2, R3‧‧‧ resistance

Sc‧‧‧ drive control signal

Sen‧‧‧Sampling Control Signal

Si1‧‧‧ first indication signal

Si2‧‧‧ second indication signal

Sovp‧‧‧Overvoltage protection signal

Suvp‧‧‧ undervoltage protection signal

VREF1‧‧‧ first reference voltage

VREF2‧‧‧second reference voltage

Vout‧‧‧AC output voltage

Vin‧‧‧DC input voltage

Vs‧‧ ‧ sampling voltage

VCC‧‧‧Power supply voltage

FIG. 1 is a schematic diagram of an AC power supply system according to an embodiment of the present invention.

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

FIG. 3 is a schematic diagram of a detection circuit according to an embodiment of the invention.

4 is a schematic diagram of a control circuit in accordance with 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 AC power supply system according to an embodiment of the present invention. Please refer to Referring to Fig. 1, in the present embodiment, the AC power supply system 10 includes a DC power source generating device 50 and an inverter device 100. Here, the AC power system 10 is exemplified by a photovoltaic grid-connected system, so the DC power generating device 50 can be, for example, a photovoltaic module PVm (but not limited thereto). The photovoltaic module PVm can be used to convert solar energy into a direct current input voltage Vin in the form of electrical energy. It is worth mentioning that the AC power system 10 is not limited to being implemented by a photovoltaic grid-connected system, and may also be a grid-connected system of a wind-connected system or other renewable energy, or an uninterruptible power system (UPS) or a large-scale system. Non-grid systems such as Back-up Power System (BPS).

The inverter device 100 receives the DC input voltage Vin output from the DC power generating device 50, and accordingly generates an AC output voltage Vout to the back-end paralleled power grid EG. The inverter device 100 can quickly detect whether the AC output voltage Vout output to the grid EG is abnormal by a simple circuit structure, so as to instantly activate the protection mechanism to adjust the operation of the inverter device 100.

The specific structure of the inverter device 100 of the embodiment of the present invention will be described below with reference to FIG. 2 is a schematic diagram of an inverter device according to an embodiment of the present invention.

Referring to FIG. 1 and FIG. 2 simultaneously, the inverter device 100 of the present embodiment includes an inverter circuit 110, a detection circuit 120, and a control circuit 130. The inverter circuit 110 receives the DC input voltage Vin from the DC power generating device 50 and converts the DC input voltage Vin into an AC output voltage Vout. 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 inverter circuit 110 and is configured to sample the AC output voltage Vout. In this embodiment, the detecting circuit 120 compares the first reference voltage VREF1 and the second reference voltage VREF2 with the sampled AC output voltage Vout, respectively, to generate the first indicator signal Si1 and the second indicator signal Si2.

The control circuit 130 is coupled to the inverter circuit 110 and the detection circuit 120 for providing a control signal Sc for controlling the power conversion operation of the inverter circuit 110. The control signal Sc can be, for example, used to control the switching of the inverter circuit 110. A pulse width modulation signal (PWM signal), but the invention is not limited thereto.

In this embodiment, the control circuit 130 receives the first indication signal Si1 and the second indication signal Si2 generated by the detection circuit 120, and judges according to the first indication signal Si1 and the second indication signal Si2 in each driving cycle. Whether the amplitude of the AC output voltage Vout is within the working voltage interval, and then determining whether to enable over voltage protection or under voltage protection to control the power conversion of the inverter circuit 110 according to the result of the judgment, thereby The AC output voltage Vout returns to the normal operating voltage range or stops the operation of the inverter circuit 110.

In detail, the operating voltage interval is defined according to the set first reference voltage VREF1 and the second reference voltage VREF2. In this embodiment, when the control circuit 130 determines that the amplitude of the AC output voltage Vout is greater than the first reference voltage VREF1 and the second reference voltage VREF2 according to the first indication signal Si1 and the second indication signal Si2, the control circuit 130 according to the first An indication signal Si1 and the second indication signal Si2 determine that the inverter circuit 110 is overvoltaged at this time, and thus the control circuit 130 At this time, overvoltage protection is enabled to control the power conversion of the inverter circuit 110. For example, when it is determined that the inverter circuit 110 is overvoltage, the control circuit 130 stops outputting the control signal Sc until the amplitude of the AC output voltage Vout returns to the operating voltage interval, and then returns the control signal Sc to the normal output.

On the other hand, when the control circuit 130 determines that the amplitude of the AC output voltage Vout is smaller than the first reference voltage VREF1 and the second reference voltage VREF2 according to the first indication signal Si1 and the second indication signal Si2, the control circuit 130 according to the first indication The signal Si1 and the second indication signal Si2 determine that the inverter circuit 110 is under voltage at this time, and therefore the control circuit 130 activates the undervoltage protection to control the power conversion of the inverter circuit 110. For example, when determining that the inverter circuit 110 is under voltage, the control circuit 130 can reduce the frequency and duty cycle of the control signal Sc, thereby limiting the output power of the inverter circuit 110 until the amplitude of the AC output voltage Vout returns to work. When the voltage range is within, the control signal Sc is restored to the normal output.

Compared with the conventional inverter device, the control circuit 130 can be used to calculate whether an overvoltage or an undervoltage occurs according to the AC output voltage. The control circuit 130 of the embodiment of the present invention can simply rely on the first indication signal Si1 and the second. The logic combination of the indication signal Si2 can determine whether the current AC output voltage Vout has an overvoltage or undervoltage condition. Therefore, the control circuit 130 of the embodiment of the present invention does not need to perform complicated operations, and can quickly determine Whether the AC output voltage Vout is abnormal. In addition, the detection circuit 120 of the embodiment of the present invention can realize the amplitude indication of the AC output voltage Vout by using a relatively simple circuit structure composed of comparators, so that the overall circuit design cost does not cause additional The burden.

The architecture of the detection circuit 120 and the control circuit 130 of the embodiment of the present invention will be described below with reference to FIGS. 3 and 4. FIG. 3 is a schematic diagram of a detection circuit according to an embodiment of the present invention. 4 is a schematic diagram of a control circuit in accordance with an embodiment of the present invention.

Referring to FIG. 3 , in the embodiment, the detecting circuit 120 includes an amplitude adjusting unit 122 , a reference voltage generating unit 124 , a first comparing unit 126 , and a second comparing unit 128 . The amplitude adjustment unit 122 receives the AC output voltage Vout, and adjusts the amplitude of the AC output voltage Vout according to the gain adjustment ratio GR, thereby generating a sampling voltage Vs associated with the AC output voltage Vout. The gain adjustment ratio GR may be generated by the control circuit 130 outputting a gain adjustment signal, or the amplitude adjustment unit 122 may be implemented by a voltage divider circuit, which may be, for example, two resistors connected in series. Two resistors divide the supply voltage Vout, and a sampling voltage Vs can be established at the node between the two resistors. The AC output voltage Vout has a multiple relationship with the sampling voltage Vs, for example, and the multiple is determined by the gain adjustment ratio GR. For example, the amplitude adjustment unit 122 can generate the sampling voltage Vs whose amplitude is half of the AC output voltage Vout according to the gain adjustment ratio GR, which is not limited thereto.

The reference voltage generating unit 124 is configured to generate the first reference voltage VREF1 and the second reference voltage VREF2. The reference voltage generating unit 124 can be implemented, for example, by resistors R1, R2, and R3 connected in series with each other. More specifically, the resistors R1 to R3 are resistor strings coupled between the power supply voltage VCC (which may be, for example, a DC voltage generated according to the AC output voltage Vout) and the ground GND. By dividing the power supply voltage VCC through the resistors R1~R3, the first parameter can be established on the nodes N1 and N2 respectively. Test voltage VREF1 and second reference voltage VREF2. In other words, the magnitudes of the first reference voltage VREF1 and the second reference voltage VREF2 may be changed according to the resistance value setting of the resistors R1 R R3, and the first reference voltage VREF1 may be greater than the second reference voltage VREF2.

The first input terminal (eg, the positive input terminal) of the first comparison unit 126 is coupled to the amplitude adjustment unit 122 to receive the sampling voltage Vs. The second input terminal (eg, the negative input terminal) of the first comparison unit 126 is coupled to the node N1 of the reference voltage generating unit 124 to receive the first reference voltage VREF1. The output of the first comparison unit 126 outputs the first indication signal Si1 according to the comparison result of the sampling voltage Vs and the first reference voltage VREF1. For example, when the voltage swing of the sampling voltage Vs at a specific time point is greater than the first reference voltage VREF1, the first comparison unit 126 generates an enabled first indication signal Si1 (eg, logic 1). Conversely, when the voltage swing of the sampling voltage Vs at a specific time point is less than the first reference voltage VREF1, the first comparison unit 126 generates the disabled first indication signal Si1 (eg, logic 0).

The first input terminal (eg, the positive input terminal) of the second comparison unit 128 is coupled to the amplitude adjustment unit 122 to receive the sampling voltage Vs. The second input terminal (eg, the negative input terminal) of the second comparison unit 128 is coupled to the node N2 of the reference voltage generating unit 124 to receive the second reference voltage VREF2. The output of the second comparison unit 128 outputs a second indication signal Si2 according to the comparison result of the sampling voltage Vs and the second reference voltage VREF2. For example, when the voltage swing of the sampling voltage Vs at a specific time point is greater than the second reference voltage VREF2, the second comparison unit 128 generates an enabled second indication signal Si2 (eg, logic 1). Conversely, when the sampling voltage Vs is specific When the voltage swing at the time point is less than the second reference voltage VREF2, the second comparison unit 128 generates a disable second indication signal Si2 (eg, logic 0).

Referring to FIG. 4 , in the embodiment, the control circuit 130 includes an AC voltage protection unit 131 , a high voltage detection unit 132 , a low voltage detection unit 133 , a drive controller 134 , and an enabling unit 135 . The AC voltage protection unit 131 is configured to generate an overvoltage protection signal Sovp and an undervoltage protection signal Suvp according to the first indication signal Si1 and the second indication signal Si2. The logical combination of the first indication signal Si1 and the second indication signal Si2 and the detection result represented by the following are shown in the following table (1):

When the AC voltage protection unit 131 receives the first indication signal Si1 and the second indication signal Si2 which are simultaneously enabled/logic 1, it is determined that the inverter circuit 110 is overvoltaged, and the overvoltage protection signal Sovp is generated. On the other hand, when the AC voltage protection unit 131 receives the first indication signal Si1 and the second indication signal Si2 that are simultaneously disabled/logic 0, it is determined that the inverter circuit 110 is undervoltage and generates an undervoltage protection signal Suvp. . In addition, if the first indication signal Si1 and the second indication signal Si2 received by the AC voltage protection unit 131 are enable/logic 1 and disable/logic 0, respectively, it indicates that the AC output voltage Vout is within the normal operating voltage interval. Therefore, the overvoltage protection signal Sovp/undervoltage protection signal Suvp indicating overvoltage or undervoltage is not generated.

The high voltage detecting unit 132 is coupled to the alternating voltage protection unit 131 and receives The first indication signal Si1. The high voltage detecting unit 132 determines whether to provide the first indication signal Si1 to the AC voltage protection unit 131 according to the received sampling control signal Sen (issued by the enabling unit 135). The low voltage detecting unit 133 is coupled to the AC voltage protection unit 131 and receives the second indication signal Si2. The low voltage detecting unit 133 also determines whether to provide the second indication signal Si2 to the AC voltage protection unit 131 according to the received sampling control signal Sen.

Specifically, the enabling unit 135 is coupled to the high voltage detecting unit 132 and the low voltage detecting unit 133 to generate the sampling control signal Sen and provide the high voltage detecting unit 132 and the low voltage detecting unit 133. The enabling unit 135 generates an enabled sampling control signal Sen during a preset period of each driving cycle, so that the high voltage detecting unit 132 and the low voltage detecting unit 133 react to the enabled sampling control signal Sen to respectively indicate the first indication. The signal Si1 and the second indication signal Si2 are supplied to the AC voltage protection unit 131. For example, the preset period may be, for example, a period in which the phase of the AC output voltage Vout/sampling voltage Vs is 0 to 180 degrees (that is, a period of a positive half cycle), or a period in which the phase is 80 to 100 degrees (ie, , the amplitude approaches the period of the peak). In this way, the possibility that the AC voltage protection unit 131 is misjudged due to voltage noise can be avoided. It should be noted, however, that the setting end of the preset period depends on the needs of the designer, and the present invention is not limited thereto.

The driving controller 134 is coupled to the inverter circuit 110 and the AC voltage protection unit 131. The driving controller 134 is configured to generate the driving control signal Sc to control the operation of the inverter circuit 110. The driving controller 134 adjusts the control signal Sc according to the overvoltage protection signal Sovp to perform overvoltage protection (for example, reducing the control signal Sc). frequency And / or responsibility cycle). In addition, the drive controller 134 also adjusts the drive control signal Sc according to the undervoltage protection signal Suvp, thereby performing undervoltage protection (eg, stopping providing the control signal Sc).

In summary, the embodiment of the invention provides an inverter device and an AC power supply system using the same. The inverter device can compare the amplitude of the AC output voltage with the reference voltage, thereby generating a plurality of indication signals according to the comparison result, and determining whether the current AC output voltage has an overvoltage according to the logical combination of the generated indication signals. The undervoltage condition occurs, so that the inverter device of the embodiment of the present invention does not need to perform complicated calculations, and can quickly determine whether an abnormality occurs in the AC output voltage. In addition, the indication signal indicating the amplitude of the AC output voltage can be realized by a relatively simple circuit architecture composed of comparators, and thus does not impose an additional burden on the overall circuit design cost.

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

Si1‧‧‧ first indication signal

Si2‧‧‧ second indication signal

Sc‧‧‧ drive control signal

VREF1‧‧‧ first reference voltage

VREF2‧‧‧second reference voltage

Vout‧‧‧AC output voltage

Claims (8)

An inverter device includes: an inverter circuit that receives a DC input voltage for converting the DC input voltage into an AC output voltage; a detection circuit coupled to the inverter circuit and configured to sample the AC An output voltage, wherein the detecting circuit compares a first reference voltage and a second reference voltage with the sampled AC output voltage to generate a first indication signal and a second indication signal; and a control circuit, The inverter circuit and the detection circuit are coupled to control the operation of the inverter circuit, wherein the control circuit determines the AC output voltage according to the first indication signal and the second indication signal in each driving cycle. Whether the amplitude is in an operating voltage interval, and when the control circuit determines that the amplitude of the AC output voltage is greater than the first reference voltage and the second reference voltage according to the first indication number and the second indication signal, the control circuit is enabled. The over voltage protection controls the power conversion of the inverter circuit, and when the control circuit is responsive to the first indication signal When the second indication signal determines that the amplitude of the AC output voltage is less than the first reference voltage and the second reference voltage, the control circuit enables the under voltage protection to control the power conversion of the inverter circuit. . The inverter device of claim 1, wherein the detecting circuit comprises: an amplitude adjusting unit that receives the AC output voltage and adjusts an amplitude of the AC output voltage according to a gain adjustment ratio, thereby generating an association with The AC output a sampling voltage of the voltage; a reference voltage generating unit for generating the first reference voltage and the second reference voltage; a first comparing unit, wherein the first input end is coupled to the amplitude adjusting unit to receive the sampling voltage, The second input end is coupled to the reference voltage generating unit to receive the first reference voltage, and the output end thereof outputs the first indication signal; and a second comparison unit, the first input end of which is coupled to the amplitude adjusting unit Receiving the sampling voltage, the second input end is coupled to the reference voltage generating unit to receive the second reference voltage, and the output end thereof outputs the second indication signal. The inverter device of claim 1, wherein the control circuit comprises: an AC voltage protection unit for generating an overvoltage protection signal and an undervoltage according to the first indication signal and the second indication signal a protection signal; a high voltage detection unit coupled to the AC voltage protection unit and receiving the first indication signal, wherein the high voltage detection unit determines whether to provide the first indication signal to the AC voltage protection unit according to a sampling control signal; a low voltage detecting unit coupled to the AC voltage protection unit and receiving the second indication signal, wherein the low voltage detecting unit determines whether to provide the second indication signal to the AC voltage protection unit according to the sampling control signal; and a driving The controller is coupled to the inverter circuit and the AC voltage protection unit for generating a driving control signal to control the operation of the inverter circuit, wherein the driving controller adjusts the control signal according to the overvoltage protection signal, thereby executing Overpressure protection And protecting the control signal according to the undervoltage protection signal, thereby performing the undervoltage protection. The inverter device of claim 3, wherein the control circuit further comprises: a matching energy unit coupled to the high voltage detecting unit and the low voltage detecting unit, and configured to generate the sampling control signal, wherein the enabling The unit generates the enabled sampling control signal during a predetermined period of the driving period, so that the high voltage detecting unit and the low voltage detecting unit respectively react the enabled sampling control signal to the first indication signal and the The second indication signal is provided to the alternating voltage protection unit. An AC power supply system comprising: a DC power generating device for generating a DC input voltage; and an inverter device coupled to the DC power generating device, wherein the inverter device comprises: an inverter circuit for receiving the DC An input voltage for converting the DC input voltage into an AC output voltage; a detection circuit coupled to the inverter circuit and configured to sample the AC output voltage, wherein the detection circuit respectively uses a first reference voltage Comparing the second reference voltage with the sampled AC output voltage to generate a first indication signal and a second indication signal; and a control circuit coupled to the inverter circuit and the detection circuit for controlling The operation of the inverter circuit, wherein the control circuit determines whether the amplitude of the AC output voltage is in accordance with the first indication signal and the second indication signal in each driving cycle In a working voltage interval, when the control circuit determines that the amplitude of the AC output voltage is greater than the first reference voltage and the second reference voltage according to the first indication number and the second indication signal, the control circuit enables the Over voltage protection to control power conversion of the inverter circuit, and when the control circuit determines that the amplitude of the AC output voltage is smaller than the first reference voltage according to the first indication signal and the second indication signal, The second control voltage enables the under voltage protection to control the power conversion of the inverter circuit. The AC power supply system of claim 5, wherein the detecting circuit comprises: an amplitude adjusting unit that receives the AC output voltage and adjusts an amplitude of the AC output voltage according to a gain adjustment ratio, thereby generating an association with a sampling voltage of the AC output voltage; a reference voltage generating unit for generating the first reference voltage and the second reference voltage; a first comparing unit, the first input end of which is coupled to the amplitude adjusting unit to receive the a sampling voltage, a second input end coupled to the reference voltage generating unit to receive the first reference voltage, and an output terminal outputting the first indication signal; and a second comparison unit having a first input end coupled to the amplitude The adjusting unit is configured to receive the sampling voltage, the second input end is coupled to the reference voltage generating unit to receive the second reference voltage, and the output end thereof outputs the second indication signal. An AC power system as described in claim 5, wherein the control The circuit includes: an AC voltage protection unit configured to generate an overvoltage protection signal and an undervoltage protection signal according to the first indication signal and the second indication signal; a high voltage detection unit coupled to the AC voltage protection unit, and Receiving the first indication signal, wherein the high voltage detection unit determines whether to provide the first indication signal to the AC voltage protection unit according to a sampling control signal; a low voltage detection unit coupled to the AC voltage protection unit, and receiving the first a second indication signal, wherein the low voltage detecting unit determines whether to provide the second indication signal to the AC voltage protection unit according to the sampling control signal; and a driving controller coupled to the inverter circuit and the AC voltage protection unit Controlling the operation of the inverter circuit by generating a driving control signal, wherein the driving controller adjusts the control signal according to the overvoltage protection signal, thereby performing the overvoltage protection, and adjusting the control signal according to the undervoltage protection signal, This undervoltage protection is performed. The AC power supply system of claim 7, wherein the control circuit further comprises: a matching energy unit coupled to the high voltage detecting unit and the low voltage detecting unit, and configured to generate the sampling control signal, wherein the enabling The unit generates the enabled sampling control signal during a predetermined period of the driving period, so that the high voltage detecting unit and the low voltage detecting unit respectively react the enabled sampling control signal to the first indication signal and the The second indication signal is provided to the alternating voltage protection unit.