AC voltage stabilizer with high safety

Abstract

The utility model relates to an alternating current voltage stabilizer with high safety, which comprises a sampling circuit, a control circuit and an output circuit which are connected in sequence, the sampling circuit comprises an input voltage sampling circuit, an output voltage sampling circuit and a current sampling circuit, and the output circuit comprises a voltage stabilization control drive circuit, an output protection circuit and an input protection circuit. The utility model provides an alternating current voltage stabilizer with high safety.

Description

Technical Field

[0001] The utility model relates to an AC voltage stabilizer, in particular to an AC voltage stabilizer with high safety. Background Art

[0002] Contact AC voltage stabilizer is suitable for various places that require stable load voltage. When the power supply voltage fluctuates, the voltage stabilizer can automatically stabilize the load voltage at the rated value. The contact voltage stabilizer is a closed-loop control system composed of a specially designed voltage regulator and a control circuit. It is an electrical device that automatically adjusts to achieve a stable output voltage. It consists of a contact voltage regulator, an automatic control circuit and a servo motor. The contact AC voltage stabilizer with a carbon brush voltage regulation structure has an excellent cost-effectiveness.

[0003] However, in the actual use and processing of voltage stabilizers, it is found that the existing control systems of voltage stabilizers in the current industry have weak adaptability, high failure rate of control boards, complex internal wiring processes, and insufficient overall reliability. For example:

[0004] 1) In the prior art, the circuit sampling and power supply of the voltage regulator control are both powered by an independent winding drawn from an autotransformer, which is then rectified, filtered and stabilized. In actual use, it is found that this power supply method is taken from the autotransformer itself, and is prone to the risk of insufficient power supply when used under extreme conditions of large grid voltage fluctuations, which will cause the control circuit to fail to work and lead to failure of the voltage regulator.

[0005] 2) In the prior art, the motor used by the voltage regulator for automatic voltage regulation is usually a DC reduction motor, and the driving circuit usually uses two transistors, NPN and PNP, to control the forward and reverse voltage regulation. During the voltage regulation process, if a card point occurs during the movement of the brush, causing the motor to stall, the motor will heat up for a long time when it is overloaded, and the motor is easily damaged. The transistor driven by the motor is also easily damaged by heat. The commonly used processing method is to connect a fuse in series in the loop or a current sampling resistor in series to sample the voltage signal and amplify it for analysis and control. However, there is little difference between the motor stalling and normal working because the DC motor uses very little current. The fuse is a standard part with a low matching degree. The current signal sampling circuit is difficult to distinguish between true and false signals due to weak signals. The above control measures are limited, the circuit control is complex, the circuit reliability is low, and the protection effect is limited.

[0006] 3) In the prior art, the forward and reverse rotation circuit of the driving motor needs to be connected to a limit switch at the limit position of the stroke, and a diode is connected in parallel to the limit switch to realize the extreme cutting off of the motor power supply to disconnect the drive for protection. When driving in the reverse direction, the parallel diode is used to realize the reverse rotation of the motor. The driving circuit controlled by this limit switch has complex wiring circuits, many processing steps, low production efficiency, and the limit switch is easy to be damaged and has poor reliability.

[0007] 4) In the prior art, the sampling link of the voltage regulator is usually calibrated by adjusting the potentiometer, but the internal structure of the potentiometer has contacts, which are prone to corrosion in long-term use, causing potential point drift or damage, resulting in poor circuit. Adjustment in production is also complicated, resulting in low production efficiency.

[0008] 5) In the prior art, if an abnormal open circuit occurs in the voltage sampling link of the voltage regulator (such as the sampling wire head falling off), the sampling signal will be lost, and the circuit will mistakenly judge that the voltage is low, driving the voltage regulator to increase the voltage, which will cause the voltage regulator to output a high voltage and create a safety hazard.

[0009] 6) In the prior art, when the voltage stabilizer is shut down and then restarted, due to the uncertainty of the position of the carbon brush of the voltage regulating mechanism in the voltage stabilizer, a high input voltage and low input impedance state may occur, which may easily cause a large startup inrush current and cause malfunction of the user-side switch.

[0010] 7) In the prior art, the voltage, current, temperature and other working information detected by the voltage stabilizer products realize overvoltage protection, undervoltage protection and overcurrent protection. The protection means usually disconnect the output end of the voltage stabilizer, focusing on the protection of the output load end of the voltage stabilizer, but rarely paying attention to the protection of the voltage stabilizer itself, especially when heat causes dangerous faults, because the voltage stabilizer itself is not disconnected from the power grid, it is not conducive to the safe operation of the voltage stabilizer.

[0011] 8) In the prior art, the main circuit structure of the voltage stabilizer adopts an autotransformer. When the input voltage is low, the corresponding output capacity is reduced. According to the product standard, users should use it according to the derating curve. Usually, the user will be reminded of this in the product body or the manual. The existing design scheme cannot effectively remind the user and perform actual control, which may easily cause the user to over-size or overload. Summary of the invention

[0012] In view of the deficiencies in the prior art, the utility model aims to provide an AC voltage stabilizer with high safety.

[0013] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: comprising a sampling circuit, a control circuit and an output circuit connected in sequence, characterized in that: the sampling circuit comprises an input voltage sampling circuit, an output voltage sampling circuit and a current sampling circuit, the output circuit comprises a voltage stabilizing control driving circuit, an output protection circuit and the input protection circuit comprises a power supply, the power supply is connected to the input voltage sampling circuit; comprising a driving chip with a built-in H bridge, the driving chip is arranged in the voltage stabilizing control driving circuit, and an overcurrent protection module is arranged in the driving chip; comprising a motor, a carbon brush, a coil and a block, the voltage stabilizing control driving circuit and the current sampling circuit are connected to the input voltage sampling circuit; The machine is connected to form a drive for the carbon brush, the coil is arranged on the periphery of the carbon brush and provides the carbon brush with sliding movement, the coil has a travel limit position, the block is arranged at the travel limit position and is located on the relative trajectory of the carbon brush movement; the sampling circuit is calibrated by IAP online programming; the input voltage sampling circuit and the output voltage sampling circuit are provided with an error prevention processing module; the control circuit has an anti-impact soft start and delayed output module; the output protection circuit is connected to the control circuit and controls the disconnection of the regulator output, and the input protection circuit is connected to the control circuit and controls the disconnection from the power supply; the sampling circuit adopts AB two-round alternating signal sampling and data processing.

[0014] The utility model is further configured as follows: the input supply voltage of the power supply is connected to the input end of the voltage stabilizer.

[0015] The utility model is further configured as follows: an over-temperature sampling protection circuit is arranged in the driving chip.

[0016] The utility model is further configured that: the control circuit has a motor stall protection module for controlling the motor to stop rotating.

[0017] The utility model is further configured that: the signal of the sampling circuit is directly connected to the control circuit after voltage reduction processing, and is written into the flash of the single-chip computer for calibration by means of IAP online programming.

[0018] The utility model is further configured to utilize timer interruption to perform AD conversion and accumulation on the instantaneous value of the sampling signal of the sampling circuit.

[0019] Beneficial effects: 1) An independent power supply is used to power the control circuit board; 2) A driver chip with a built-in H-bridge is used as the motor drive circuit; 3) The motor control circuit adopts a limit switch-free design; 4) The system has motor stall protection and limit automatic stop functions; 5) The calibration of the sampling circuit signal adopts IAP online programming instead of potentiometer; 6) The sampling circuit signal has an error-proof processing function for abnormal open circuit detection protection; 7) It has anti-shock soft start and delayed output functions; 8) The system adopts dual protection functions for the output and input ends; 9) The system dynamically detects and controls the load to accurately achieve overload protection; 10) The AB two-round alternating signal sampling and data processing are used to ensure accurate and reliable voltage stabilization control. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flowchart of the overall utility model;

[0021] Figure 2 A circuit diagram of a power supply in the present utility model;

[0022] Figure 3 It is a circuit diagram of a linear voltage-stabilized power supply circuit in a general design scheme;

[0023] Figure 4 This is a circuit diagram of a voltage stabilizing control driving circuit in the utility model;

[0024] Figure 5 It is the circuit diagram of the transistor motor drive circuit in the general design scheme;

[0025] Figure 6 This is a schematic diagram of the installation of the limit switch and diode on the coil in the general design scheme;

[0026] Figure 7 It is a circuit diagram of an input voltage sampling circuit and an output voltage sampling circuit in the utility model;

[0027] Figure 8 It is a circuit diagram of a voltage sampling circuit in a general design scheme;

[0028] Fig. 9 It is a circuit diagram of the control circuit in the utility model;

[0029] Fig.10 It is a circuit diagram of the input protection circuit and the output protection circuit in the utility model;

[0030] Fig.11 A curve diagram showing the relationship between input voltage and output capacity of the voltage stabilizer in the utility model;

[0031] Fig.12 It is a schematic diagram of the flow of alternate sampling and data processing of two rounds of signals AB in the present utility model;

[0032] Fig.13 It is a structural schematic diagram of the motor, carbon brush, coil, block and related components in the utility model.

[0033] In the figure: 1. Mounting plate; 2. Diode; 3. Limit switch; 4. Coil; 5. Carbon brush; 6. Motor; 7. Fixing part; 8. Stop block. DETAILED DESCRIPTION

[0034] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0035] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0036] like Figure 1-13As shown, the utility model discloses a highly safe AC voltage stabilizer, comprising a sampling circuit, a control circuit and an output circuit connected in sequence, wherein the sampling circuit comprises an input voltage sampling circuit, an output voltage sampling circuit and a current sampling circuit, the output circuit comprises a voltage stabilization control drive circuit, an output protection circuit and the input protection circuit comprises a power supply, the power supply is connected to the input voltage sampling circuit; comprises a driving chip with a built-in H bridge, the driving chip is arranged in the voltage stabilization control drive circuit, an overcurrent protection module is arranged in the driving chip; comprises a motor, a carbon brush, a coil and a block, the voltage stabilization control drive circuit is connected to the motor and constitutes a drive for the carbon brush, the contact area between the coil and the carbon brush is polished to ensure good Electrical connection, the coil has a travel limit position, the block is set at the travel limit position and is located on the relative trajectory of the carbon brush movement; the sampling circuit is calibrated using IAP online programming; the input voltage sampling circuit and the output voltage sampling circuit are provided with error prevention processing modules; the control circuit has an anti-impact soft start and delayed output module; the output protection circuit is connected to the control circuit and controls the disconnection of the voltage regulator output, and the input protection circuit is connected to the control circuit and controls the disconnection from the power supply; the sampling circuit adopts AB two rounds of alternating signal sampling and data processing. It should be noted that the motor, carbon brush, coil and block constitute a voltage regulating mechanism, and the block can be fixed to the coil by a fixing, and the control circuit is an MCU microcontroller.

[0037] The input supply voltage of the power supply is connected to the input terminal of the voltage regulator.

[0038] An over-temperature sampling protection circuit is provided in the driver chip.

[0039] The control circuit has a motor stall protection module for controlling the motor to stop.

[0040] The signal of the sampling circuit is directly connected to the control circuit after voltage reduction, and is written into the flash of the microcontroller for calibration by IAP online programming.

[0041] Using the timer interrupt, the instantaneous value of the sampling signal of the sampling circuit is AD converted and accumulated.

[0042] In view of problem 1 in the background technology, an independent power supply is used to power the control circuit board; Figure 2 As shown in the figure, the input power supply voltage of the power supply is taken from the input end of the voltage stabilizer, which can work in a wide voltage range of 80~300V and is not affected by the voltage stabilizer itself. It can still provide stable voltage supply when used under extreme conditions with large grid voltage fluctuations, ensuring the stable power supply of the voltage stabilizer's own control system. In the general design scheme, the control system power supply adopts a linear power supply such as Figure 3The power supply end is taken from the output end of the voltage regulator, usually by independently winding the low-voltage winding in the voltage regulating transformer, and is realized after rectification, filtering and voltage stabilization by linear devices. This type of power supply circuit has low output efficiency. When used under extreme conditions with large grid voltage fluctuations, due to the response lag of the voltage regulator carbon brush voltage regulation, when the voltage regulator input drops to a low voltage, this type of power supply will have insufficient supply voltage, causing control reset or system failure. On the other hand, when the input voltage rises rapidly, the linear device circuit is easily damaged after being impacted, causing the voltage regulator control system to fail.

[0043] In view of problem 2 in the background technology, this system uses a driver chip with a built-in H bridge and is set in a voltage stabilization control drive circuit. Figure 4 As shown, U5 is a driver chip, which has a built-in H-bridge power tube and control module. The input Up boost and Down drive adopts PWM wave for regulation, and the motor supply voltage can be regulated according to the demand. The driver chip has overcurrent protection, which can be set through R20 and R21, and sampled through R19. When the motor current reaches the set value, the motor power supply can be disconnected. The built-in over-temperature sampling protection circuit can disconnect the motor power supply when the temperature is too high. After adopting this circuit, the drive circuit can be used more stably and reliably without software participation; while the voltage stabilization control drive circuit of the existing technology ( Figure 5 As shown in the figure, two transistors, NPN and PNP, are usually used to control the forward and reverse voltage regulation. During the voltage regulation process, if a card point occurs during the movement of the brush, causing the motor to stall, the F1 fuse in the series circuit usually has only short-circuit protection. The actual current difference between the motor stalling and working is small, and the fixed protection value is difficult to match. The motor cannot be effectively protected when it is stalled, and the circuit has no over-temperature protection. The transistor driven by the motor is prone to heat and damage during long-term stalling. The input UP boost and Down drive signals of this circuit can only use high and low levels, the motor power supply cannot be adjusted, and the VCC-VCC power supply has no voltage stabilization. During actual operation, the motor has a large impact, and the transistors Q1 and Q2 are easily damaged by voltage impact, and the circuit reliability is low.

[0044] In view of problem 3 in the background technology, a design scheme without limit switch is adopted, and the load end of the voltage stabilization control drive circuit is directly connected to the motor ( Figure 4 The M in the circuit is simple. The load end of the existing general technology motor drive circuit needs to be connected in series with a limit switch and a diode in the motor circuit ( Figure 5 SB1, SB2, D5, D6) in the wiring is complex and the assembly process is complex; in general technology (such as Figure 6 As shown), a limit switch is provided at the limit position of the sliding stroke of the carbon brush on the coil. When the carbon brush rotates, the limit switch is triggered ( Figure 5 SB1, SB2) are used to cut off the driving power of the motor. In order to facilitate the reverse drive of the motor, a diode ( Figure 5D5, D6), while in this system, a stopper is set at the limit position of the coil, and there is no need to connect a limit switch and a parallel diode, which simplifies the processing procedure of the voltage stabilizer, improves production efficiency, and avoids the risk of limit switch failure; the control circuit has a motor stall protection module. When the motor drives the carbon brush to the limit position of the limit coil, the motor stall protection module is enabled, which can realize the limit automatic stop function, cut off the motor drive in time, and realize the motor stop. When driving in the reverse direction, the motor power will also automatically recover;

[0045] At the same time, the system has the functions of motor stall protection and limit automatic stop. As mentioned above, the implementation method of the motor stall protection and limit automatic stop function of the system is: the system determines whether the motor is in the limit position or stall state by detecting the motor driving time and calculating the output voltage difference to achieve protection. According to the product characteristics of the voltage stabilizer, due to the change of input voltage, the voltage regulating mechanism of the voltage stabilizer will adjust the voltage according to the circuit instruction to stabilize the output voltage. During normal voltage regulation, the voltage value output by the voltage regulating mechanism should always be a relatively stable voltage value. When voltage stabilization operation is required, the voltage stabilization control drive circuit drives the motor to drive the carbon brush to regulate the voltage. The absolute value of the difference between the output voltage values ​​at the starting point and the end point in unit time should be less than a set value of the system. When the carbon brush is blocked, this value will increase. That is, assuming that the unit time period of the motor operation is from point a to point b, the absolute value of the output voltage difference between these two time points is |Va -Vb|value, when the normal voltage-stabilized motor should operate normally, this value should be less than the system setting value. If this value is larger, it can be determined that the motor is blocked. At this time, the motor drive signal is cut off. When the drive signal is generated in the opposite direction, the block protection is automatically exited. The system exits the block protection, thus realizing the motor block protection function. In order to prevent occasional card points or misjudgment of malfunctions, the system can repeat the operation twice. If the secondary judgment is still true, it is a true block, then the motor drive signal is cut off. When the drive signal is generated in the opposite direction, the block protection is automatically exited. The system exits the block protection, thus realizing the motor block protection function; the above-mentioned motor block detection and protection method can realize the protection of the motor when the carbon brush finds a block at any point in the coil stroke, and at the same time, it can realize the automatic cutting off of the motor drive signal when the carbon brush is in the extreme position and touches the block to cause a block, thereby realizing the limit automatic stop function, without the need to connect a limit switch and a parallel diode.

[0046] In view of problem 4 in the background technology, the signal calibration of the sampling circuit of the system adopts IAP online programming instead of potentiometer; in the prior art, the sampling link of the voltage regulator control circuit is usually calibrated by adjusting the potentiometer, such as Figure 8 As shown in the figure, D7, D8, R3, R4, R6, R7, C6, C9, and RP1 form a sampling circuit, in which the RP1 potentiometer is used to calibrate the voltage. Since there are contacts in the internal structure of the potentiometer, it is easy to corrode in long-term use, causing the potential point to drift or be damaged, resulting in circuit failure; Figure 7 The sampling circuit of this system does not have a potentiometer. The signal is directly connected to the MCU chip after voltage reduction. It is written into the flash of the MCU for calibration through IAP online programming. The specific implementation method is to short-circuit P6 for a moment when the product is calibrating the system (see Fig. 9 ), the system can complete the data calibration operation, which is easy to operate and avoids the unreliability of the circuit caused by the use of potentiometers.

[0047] In view of problem 5 in the background technology, the input voltage sampling circuit and the output voltage sampling circuit are provided with an error prevention processing module; in existing general applications, such as Figure 8 As shown in the figure, if the voltage sampling link of the voltage regulator has an abnormal open circuit (such as the sampling 15V winding wire head falls off and opens the circuit), the voltage signal of the voltage signal sampling circuit composed of D7, D8, R3, R4, R6, R7, C6, C9, and RP1 will be lower than the actual value. At this time, the circuit will mistakenly judge that the sampling voltage is low, and the voltage regulating mechanism will be driven to increase the voltage, which will cause the voltage regulator to output a high voltage and cause safety hazards. This system has a disconnection detection function, such as Figure 7 When the voltage sampling signal of LR1, LR2 or LR3, LR4 is open, the system will control the driving voltage regulating mechanism to complete the voltage reduction regulation and automatically alarm, which can avoid the shortcomings of circuit control in existing general applications.

[0048] In view of problem 6 in the background technology, the system has an anti-shock soft start and delayed output module. In the actual application of the voltage stabilizer, the voltage stabilizer will shut down when the carbon brush is at the low end, and the voltage stabilizer will start when the input high voltage is turned on. Figure 7 As shown, at this time, the carbon brush TC of the voltage regulator is located at the low end of the coil T, which will make the impedance Z value of the input circuit of the voltage regulator small. Combined with the high voltage U value at startup, according to Ohm's law, I=U / Z, the input current I value will become larger at this time. Excessive input current will cause the circuit breaker at the upper end of the voltage regulator to malfunction. At the same time, under this working condition, because the voltage regulating coil of the voltage regulator is an autotransformer, according to the principle of autotransformer, the output voltage will also be a high voltage. In order to avoid the above situation, the anti-impact soft start startup and delayed output module of this system are implemented The method is: when starting up, the drive motor drives the carbon brush TC to rotate in the direction of high impedance of the line for a certain period of time by default (the rotation time is determined by the rotation stroke of the carbon brush and the motor speed), and then the system enters the voltage regulation control. After the voltage regulator stabilizes the voltage, the system starts output. The time from starting up to the output of the voltage regulator is the delayed output time of the voltage regulator. When starting up, the carbon brush turns to high impedance, which can effectively reduce the startup inrush current and achieve the anti-shock soft start function. The delayed output can ensure that the system output voltage is stable after the output voltage is output, ensuring the safe use of the voltage regulator.

[0049] In view of problem 7 in the background technology, the system adopts an output protection circuit and an input protection circuit, such as Figure 1 , Figure 7 and Fig.10 As shown, after the system analyzes the input voltage signal, output voltage signal, current signal, temperature signal and other data through the control circuit, it can control QF1 to cut off the input power supply through the input protection circuit, and control KM1 to disconnect the output of the voltage regulator through the output protection circuit. The input and output protection control can be set according to the actual situation. For example, for general faults or abnormalities such as output overvoltage, the output protection function can be executed. For abnormalities involving safety, such as overtemperature and overload, the input release QF1 can be disconnected through the input protection control circuit. After the input protection is executed, the voltage regulator can be disconnected from the power grid to ensure the safety of the product.

[0050] In response to problem 8 in the background technology, this system uses two rounds of alternating signal sampling and data processing to ensure accurate and reliable voltage control. Fig.12 As shown, in the interrupt program, the timer interrupt is used to perform AD conversion and accumulation on the instantaneous value of the AC sampling signal. To improve the accuracy, a sine wave can be sampled 64 times or more, and then the data is accumulated and processed. In the main program, the cached data is processed to obtain the actual effective value, and the voltage stabilization control and other controls are completed. The advantage over the general processing method is that this system uses AB two-round sampling and data processing control, which can enhance the anti-interference ability of the voltage stabilizer in complex environments, improve the timeliness of operation response, and ensure the reliable operation of the system.

[0051] This system dynamically detects and controls the load to accurately achieve overload protection. Since most contact voltage stabilizers use auto-voltage regulators to control the voltage to achieve the voltage stabilization function, according to the capacity characteristics of the auto-transformer, the lower the input voltage, the lower the corresponding output capacity. The derating curve is as follows: Fig.11 The voltage stabilizer usually only prompts the user in the product body or manual to use the selected load according to the derating curve. Due to the uncertainty of the grid voltage and the change of the load, the user cannot actually control it, which may easily cause the user to over-size or overload. This system combines the sampled data of the output capacity curve characteristics with the input voltage sampled data and the load current to accurately calculate according to the curve, and dynamically displays the current load on the display interface. When the overload protection action value is reached, an alarm is issued and the protection operation is performed.

Claims

1. An AC voltage stabilizer with high safety, comprising a sampling circuit, a control circuit and an output circuit connected in sequence, characterized in that: The sampling circuit includes an input voltage sampling circuit, an output voltage sampling circuit and a current sampling circuit, and the output circuit includes a voltage stabilization control drive circuit, an output protection circuit and an input protection circuit; It also includes a power supply, which is connected to the input voltage sampling circuit; It also includes a driver chip with a built-in H bridge, the driver chip is arranged in a voltage stabilization control drive circuit, and an overcurrent protection module is arranged in the driver chip; It also includes a motor, a carbon brush, a coil and a stopper. The voltage stabilizing control driving circuit is connected to the motor and drives the carbon brush. The coil is arranged on the outer periphery of the carbon brush and allows the carbon brush to slide. The coil has a stroke limit position. The stopper is arranged at the stroke limit position and is located on the relative trajectory of the carbon brush. The sampling circuit is calibrated using IAP online programming; The input voltage sampling circuit and the output voltage sampling circuit are provided with an error prevention processing module; The control circuit has anti-shock soft start and delayed output module; The output protection circuit is connected to the control circuit and controls the disconnection of the output of the voltage regulator, and the input protection circuit is connected to the control circuit and controls the disconnection from the power supply; The sampling circuit adopts two rounds of AB alternating signal sampling and data processing.

2. The AC voltage stabilizer with high safety according to claim 1, characterized in that: The input supply voltage of the power supply is connected to the input terminal of the voltage regulator.

3. The AC voltage stabilizer with high safety according to claim 1, characterized in that: An over-temperature sampling protection circuit is provided in the driver chip.

4. The AC voltage stabilizer with high safety according to claim 1, characterized in that: The control circuit has a motor stall protection module for controlling the motor to stop.

5. The AC voltage stabilizer with high safety according to claim 1, characterized in that: The signal of the sampling circuit is directly connected to the control circuit after voltage reduction, and is written into the flash of the microcontroller for calibration by IAP online programming.

6. The AC voltage stabilizer with high safety according to claim 1, characterized in that: Using the timer interrupt, the instantaneous value of the sampling signal of the sampling circuit is AD converted and accumulated.

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