CN118219177A - Electric tool and method for obtaining phase information of AC signal - Google Patents

Abstract

The application discloses an electric tool and a method for acquiring phase information of an alternating current signal, wherein the electric tool comprises the following components: a housing; the power supply input device is used for connecting an alternating current signal so as to provide electric energy required by the electric tool during operation; a motor; a drive circuit electrically connected to the motor; the driving circuit is used for driving the motor; the controller is electrically connected with the driving circuit and is used for outputting a control signal to the driving circuit so as to control the motor to run; the signal processing device comprises a phase shifting module; the phase shifting module is used for converting the alternating current electric signal into a first electric signal and a second electric signal; the first electrical signal and the second electrical signal have the same amplitude and differ in phase angle by 90 degrees; the signal processing device is also used for acquiring phase information of the alternating current signal accessed by the power input device according to the first electric signal and the second electric signal; the controller is configured to regulate the control signal based on the phase information. The scheme provided by the application can accurately acquire the phase information of the alternating current signal.

Description

Electric tool and method for obtaining phase information of AC signal

Technical Field

The present application relates to the field of power electronics technology, and in particular to an electric tool and a method for acquiring phase information of an alternating current signal.

Background technique

During the operation of AC tools (such as high-voltage brushless angle grinders), it is necessary to detect input and output for closed-loop negative feedback control. However, input signals often have interference and distortion, which affects the control strategy. Therefore, it is necessary to accurately obtain the phase, frequency and other information of the input signal. In related technologies, it is common to determine the waveform of the input signal by detecting the zero crossing point. If the wiring harness is too long or there is other environmental interference, the sine wave has large burrs, especially if it oscillates frequently near the zero crossing point, which can easily lead to large detection deviations.

Summary of the invention

The embodiment of the present application provides a method for obtaining phase information of an electric tool and an alternating current signal, so that the phase information of the input signal can be accurately obtained even when the input signal of the electric tool is unstable.

In a first aspect, an embodiment of the present application provides an electric tool, comprising:

case;

A power input device, used to receive an AC signal to provide the power tool with the power required for operation;

motor;

A drive circuit, electrically connected to the motor; the drive circuit is used to drive the motor;

a controller, electrically connected to the drive circuit, and configured to output a control signal to the drive circuit to control the operation of the motor;

A signal processing device, comprising a phase shift module; the phase shift module is used to convert the AC signal into a first electrical signal and a second electrical signal; the first electrical signal and the second electrical signal have the same amplitude and a phase angle difference of 90°; the signal processing device is also used to obtain phase information of the AC signal connected to the power input device according to the first electrical signal and the second electrical signal;

The controller is configured to regulate the control signal based on the phase information.

In a second aspect, an embodiment of the present application provides a method for acquiring phase information of an alternating current signal, wherein the alternating current signal is used to provide electric energy for an electric tool or an energy storage device, and the method includes:

Processing the alternating current signal through a phase shift module to obtain a first electrical signal and a second electrical signal;

The first electrical signal and the second electrical signal are processed by a phase-locked loop module to obtain phase information of the AC electrical signal; wherein the first electrical signal and the second electrical signal have the same amplitude and a phase angle difference of 90°.

In the present application, a signal processing device is provided in the electric tool. When the power input device of the electric tool is connected to the working power supply of the AC signal to control the driving circuit to drive the motor and thus drive the electric tool to work, the signal processing device can perform phase shift processing on the AC signal to obtain the first electric signal and the second electric signal, and obtain the precise phase information of the AC signal according to the first electric signal and the second electric signal, so that the controller can control the operation of the motor based on the above phase information. Even if the output voltage of the AC signal connected to the electric tool is unstable due to interference and distortion, the electric tool in the embodiment of the present application can accurately obtain the phase information of the input signal to avoid the above interference and distortion from affecting the control strategy of the working state of the electric tool.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of an electric tool provided in an embodiment of the present application;

FIG2 is a control block diagram of a signal processing device provided in an embodiment of the present application;

FIG3 is a Bode diagram of the transfer function provided in an embodiment of the present application;

FIG4 is a schematic diagram of the structure of a signal processing device provided in an embodiment of the present application;

FIG5 is a control block diagram of another signal processing device provided in an embodiment of the present application;

FIG6 is a Bode diagram of the transfer function corresponding to the control block diagram in FIG5 ;

FIG7 is a control block diagram of another signal processing device provided in an embodiment of the present application;

FIG8 is a schematic structural diagram of another electric tool provided in an embodiment of the present application;

FIG9 is a schematic flow chart of a method for acquiring phase information of an alternating current signal provided in an embodiment of the present application.

Detailed ways

The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only the parts related to the present application, rather than all structures, are shown in the accompanying drawings.

It will be understood by those of ordinary skill in the art that relative terms (e.g., "about," "approximately," "substantially," "substantially," etc.) used in conjunction with quantities or conditions are inclusive of the values and have the meaning indicated by the context (e.g., the term includes at least the degree of error associated with the measurement of the particular value, the tolerance associated with the particular value (e.g., manufacturing, assembly, use), etc.). Such terms should also be considered to disclose a range defined by the absolute values of the two endpoints. Relative terms may refer to plus or minus a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Of course, numerical values that do not employ relative terms should also be disclosed as specific values with tolerances.

From the above, it can be seen that during the operation of the AC tool, it is necessary to accurately obtain the phase, frequency and other information of the input signal to perform negative feedback control of the input or output, thereby executing the control of the motor in the AC power tool. In addition, when the motor is running, it is necessary to accurately detect the rotor position and speed. The speed and relative position of the motor can be determined by detecting the frequency and phase of the three-phase back-electromotive force waveform formed by the rotor on the stator. In other words, being able to accurately obtain the phase information of the input signal is crucial to the operation of the AC tool.

FIG1 is a schematic structural diagram of an electric tool as a specific embodiment of the present application, the electric tool comprising: a housing 11;

A power input device 12, used to receive an AC signal to provide the power tool with the power required for operation;

Motor 13;

The driving circuit 14 is electrically connected to the motor 13; the driving circuit 14 is used to drive the motor;

The controller 16 is electrically connected to the driving circuit 14 and is used to output a control signal to the driving circuit 14 to control the operation of the motor 13;

The signal processing device 15 includes a phase shift module 151; the phase shift module 151 is used to convert an AC signal into a first electrical signal and a second electrical signal; the first voltage signal and the second electrical signal have the same amplitude, and the phase angles differ by 90°. Specifically, the first electrical signal and the AC signal have the same amplitude and the same phase angle. The second electrical signal and the first electrical signal have the same amplitude, and the phase angles differ by 90°. The signal processing device 15 is also used to obtain phase information of the AC signal connected to the power input device 12 based on the first electrical signal and the second electrical signal output by the phase shift module 151; the controller 16 is configured to regulate the control signal based on the obtained phase information.

In the embodiment of the present application, a signal processing device is provided in the electric tool. When the power input device of the electric tool is connected to the working power supply of the AC signal to control the driving circuit to drive the motor and thus drive the electric tool to work, the signal processing device can perform phase shift processing on the AC signal to obtain the first electric signal and the second electric signal, and obtain the precise phase information of the AC signal according to the first electric signal and the second electric signal, so that the controller controls the operation of the motor based on the above phase information. Even if the output voltage of the AC signal connected to the electric tool is unstable due to interference and distortion, the electric tool in the embodiment of the present application can accurately obtain the phase information of the input signal to avoid the above interference and distortion from affecting the control strategy of the working state of the electric tool.

The above is the core idea of this application. The technical solutions in the embodiments of this application will be described clearly and completely below in conjunction with the drawings in the embodiments of this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

Power tools are devices that use motors to drive parts to move and complete certain tasks, such as cutting machines, angle grinders, etc. In this embodiment, the power tools are generally high-voltage power tools, which are connected to an AC voltage of 220V or even higher to control the motor to perform high-intensity movements. High-voltage power tools are widely used in the processing of metals, food materials, wood, ceramics and other materials, accelerating the process of industrialization.

In this embodiment, the electric tool includes a housing 11, and a power input device 12, a drive circuit 14, a motor 13, a signal processing device 15 and a controller 16 located inside the housing 11. The housing 11 is used to protect multiple components inside it to prevent them from being interfered with by the outside world. The power input device 12 is used to connect the working power required for the power tool to work. The working power of this embodiment is an AC signal, which is one phase of the three-phase AC mains, for example, it can be one phase of the 120V or 220V AC mains. The drive circuit 14 can drive the motor 13 to rotate, and the rotating motor 13 can drive the moving parts to move to complete various operations of the electric tool. It should be noted that in this embodiment, the electric tool includes a signal processing device 15, which is electrically connected to the power input device 12, and is used to obtain the phase information of the AC signal after removing interference and fluctuations according to the AC signal input by the power input device 12. Specifically, the signal processing device 15 may include a phase shift module 151, which can convert the AC signal into a first electrical signal and a second electrical signal having an orthogonal relationship. The first electrical signal has the same amplitude and phase angle as the alternating current signal; the second electrical signal has the same amplitude and phase angle as the alternating current signal, and lags behind the alternating current signal by 90°.

In some embodiments, with continued reference to FIG. 1 , the signal processing device 15 further includes a phase-locked loop module 153; the phase-locked loop module 153 is used to access the first electrical signal and the second electrical signal output by the phase shift module 151, and output the phase information of the AC electrical signal. The phase shift module 151 outputs the first electrical signal and the second electrical signal to the phase-locked loop module 153, and the phase-locked loop module 153 processes the input first electrical signal and the second electrical signal, thereby outputting the phase information of the AC electrical signal. In some embodiments, the phase-locked loop module 153 includes but is not limited to an orthogonal phase-locked loop or a DQ conversion module, which is not specifically limited in this embodiment.

In some embodiments, the controller 16 is configured to control the operation of the motor based on the phase information of the AC signal obtained. Specifically, the motor is a brushless motor. The control signal output by the controller is a PWM signal. The controller is configured to reduce the duty cycle of the PWM signal when the phase of the AC signal is 90° or 270°, thereby controlling the current flowing through the drive circuit.

In some embodiments, the above-mentioned method for obtaining the phase information of the AC signal can also be applied to the field of charging technology of energy storage devices. Specifically, the energy storage device is a battery pack. The battery pack is connected to the mains through a charger, that is, the AC signal is charged. When the AC signal is electrically connected to the charger to charge the battery pack, the power factor of the charging system can be corrected by obtaining the phase information of the AC signal, thereby improving the charging efficiency and the charging reliability.

In some embodiments, the above-mentioned method for obtaining the phase information of the AC signal can also be applied to the case of reverse charging of the power grid. Specifically, the energy storage device can feed back the electric energy stored in it to the power grid in some cases. When the energy storage device feeds the power grid, it is necessary to determine whether the active power or reactive power is currently transmitted on the power grid. Those skilled in the art should understand that in the process of the power grid transmitting power to the user, there are two types of electric power percentages that the power grid has to provide to the load: active power and reactive power. Active power refers to the electric power required to keep the equipment running, that is, the electric power degree of converting electric energy into other forms of energy (mechanical energy, light energy, thermal energy, etc.). Reactive power refers to the electric power required to establish a magnetic field when components such as inductors and capacitors in electrical equipment work. In fact, when the energy storage device is configured to feed power to the power grid, it is necessary to determine whether the current power grid transmits active power or reactive power, and feed power to the power grid when the current power grid transmits active power. In fact, after obtaining the phase information of the AC signal output by the power grid, the state of the current power grid can be determined. That is, whether the current transmission is active power or reactive power. In this way, the phase information of the power grid is obtained based on the method of obtaining the phase information of the AC signal in the present application, thereby controlling the operation of feeding the power grid and avoiding energy waste.

As shown in FIG2 , FIG2 is a control block diagram of a signal processing device provided in an embodiment of the present application. In some embodiments, a second-order generalized integrator is used to reconstruct the collected voltage variables and current variables. The input of the second-order generalized integrator is a single-phase input voltage signal v, which is generally a noisy sine wave signal. Through the phase shift module 151, two orthogonal relatively noise-free first electrical signals v' and second electrical signals qv' are output. The transfer function between the two output quantities and the input quantity is:

Where k is the attenuation coefficient and ω ₀ is the resonant angular frequency.

Continuing to refer to FIG. 2, in some embodiments, the phase shift module 151 may include a bandpass filter and a first low-pass filter; the phase shift module 151 is specifically used to filter out high-frequency interference signals and low-frequency interference signals from the AC signal v through the bandpass filter to obtain a first electrical signal v'; the phase shift module 151 is also specifically used to filter out high-frequency interference signals from the AC signal v through the first low-pass filter to obtain a second electrical signal qv'. That is, the phase shift module 151 itself has a bandpass filter and a first low-pass filter. The AC signal v passes through the bandpass filter to remove high-frequency interference signals and low-frequency interference signals, and obtains a first electrical signal v' with unchanged amplitude and phase. The AC signal v passes through a low-pass filter to filter out high-frequency interference signals, and obtains a second electrical signal qv' with unchanged amplitude and a phase angle difference of 90°.

1 and 2 , the embodiment of the present application can convert a noisy AC electric signal v into two orthogonal relatively noise-free first electric signal v' and second electric signal qv' through a phase shift module 151 for subsequent acquisition of phase information.

FIG3 is a Bode diagram of the above transfer function provided by an embodiment of the present application. In FIG3 , the horizontal coordinates of the Bode diagrams H _d (s) and H _q (s) represent the frequency f, the vertical coordinates on the left represent the amplitude T, and the vertical coordinates on the right represent the phase angle θ. Then the solid line T _v (f) represents the amplitude curve of the first electrical signal v', and the dotted line θ _v (f) represents the phase curve of the first electrical signal v'. Similarly, the solid line T _qv (f) represents the amplitude curve of the second electrical signal qv', and the dotted line θ _qv (f) represents the phase curve of the second electrical signal qv'. As can be seen from FIG3 , H _d (s) is a bandpass filter, and near 50 Hz, the amplitude remains unchanged and the phase angle shift is 0 degrees, while H _q (s) is a low-pass filter, and near 50 Hz, the amplitude remains unchanged and the phase angle is 90 degrees backward. The design that meets our expectations generates two waveforms with unchanged assignments and orthogonal to each other.

In some embodiments, as shown in Figure 4, the signal processing device 15 also includes: a compensation module 152; the signal processing device 15 is also used to remove the low-frequency interference signal and the DC bias signal of the second electrical signal through the compensation module 152 to obtain a third electrical signal; the signal processing module 15 is used to obtain the phase information of the AC electrical signal based on the first electrical signal and the third electrical signal.

In order to further remove the noise of the second electrical signal, the present embodiment removes the low frequency or DC bias voltage in the second electrical signal through the compensation module 152. Since the adaptive filter of the phase shift module 151 itself is a low-pass filter and cannot filter the low frequency or DC bias part, the present embodiment can add reverse compensation after the second electrical signal to remove the influence of the low frequency or DC bias and obtain the third electrical signal. In other words, the third electrical signal is the second electrical signal after the noise is removed, and can also be called an accurate second electrical signal. The signal processing module 15 can obtain the phase information of the AC electrical signal more accurately based on the first electrical signal and the third electrical signal.

In some embodiments, as shown in Figures 2 and 4, the signal processing device 15 also includes: a feedback module 154; the feedback module 154 is used to subtract the AC signal v from the first electrical signal v', and output the first difference signal ε to the phase shift module 151; so that the phase shift module 151 regulates the first electrical signal v' and the second electrical signal qv' according to the first difference signal ε, and obtains stable and controllable first electrical signal v' and second electrical signal qv', which is conducive to obtaining more accurate phase information of the AC signal.

FIG5 is a control block diagram of another signal processing device provided by an embodiment of the present application. Referring to FIG4 and FIG5, in some embodiments, the compensation module 152 may include a second low-pass filter LPF; the compensation module 152 is used to filter the first difference signal ε through the second low-pass filter LPF and then compensate the second electric signal qv' to obtain a third electric signal _qvi ', specifically, the first difference signal ε is obtained through the AC signal v and the first electric signal v'; the first difference signal ε is passed through the low-pass filter LPF to obtain a fourth voltage signal q1v' with high-frequency interference signals removed; the fourth voltage signal q1v' is inverted and compensated to the second electric signal qv' to form a third electric signal _qvi '. The control block diagram shown in FIG5 is a third electric signal _qvi ' obtained by adding reverse compensation after the second electric signal qv', which effectively removes low-frequency and DC components and improves the control accuracy of the electric tool.

FIG6 is a Bode diagram of the transfer function corresponding to the control block diagram in FIG5 . The solid line T _v (f) represents the amplitude curve of the first electrical signal v', and the dotted line θ _v (f) represents the phase curve of the first electrical signal v'. The solid line T _qv2 (f) represents the amplitude curve of the third electrical signal _qvi ', and the dotted line θ _qv2 (f) represents the phase curve of the third electrical signal _qvi '. It has no effect on the Bode diagram H _d (s), which is a bandpass filter. Near 50HZ, the amplitude remains unchanged and the phase angle shift is 0 degrees. However, the Bode diagram H _q' (s) of the third electrical signal _qvi ' is different from H _q (s) in FIG3 . H _q' (s) forms the effect of a bandpass filter, shielding the low-frequency or DC bias, and effectively improving the control accuracy of the power tool.

FIG7 is a control block diagram of another signal processing device provided in an embodiment of the present application. Referring to FIG4 and FIG7, in some embodiments, the compensation module 152 may include a high-pass filter HPF; the compensation module 152 is specifically used to remove low-frequency interference signals and DC bias signals from the AC signal v through the high-pass filter HPF to obtain a compensated AC signal v; and the compensated AC signal v is converted into an orthogonal first electrical signal v' and a second electrical signal qv' through a phase shift module 151. In this embodiment, a high-pass filter is added after the AC signal v for filtering to remove the influence of low frequency or DC bias, and the AC signal v with low-frequency noise removed is passed through the phase shift module 151 to obtain an orthogonal first electrical signal v' and a second electrical signal qv'. At this time, the second electrical signal qv' is the compensated voltage signal, which is convenient for improving the control accuracy of the power tool.

FIG8 is a schematic diagram of the structure of another electric tool provided in an embodiment of the present application. In some embodiments, the electric tool may be an angle grinder; the electric tool may further include: a chuck device 21 and an angle grinding disc (not shown in FIG8 ); the chuck device 21 is connected to one end of the housing 11; the angle grinding disc is detachably connected to the chuck device 21; a motor (not shown in FIG8 ) is used to drive the chuck device 21 to rotate, so that the chuck device 21 drives the angle grinding disc to rotate. The electric tool may be a cutting machine or an angle grinder, etc., and this embodiment is schematically illustrated by using a specific example of an angle grinder. The motor is used to drive the chuck device 21 to rotate, and the chuck device 21 can be detachably connected to the angle grinding disc, so that the motor can drag the angle grinding disc to rotate. The angle grinder in this embodiment may be a handheld angle grinder, and the housing 11 constitutes the outer structure of the angle grinder and also forms a handle for the user to hold.

Continuing to refer to FIG8 , in some embodiments, the electric tool may further include: a shield 23; the shield 23 is partially disposed around the angle grinding disc 22. The shield 23 is mainly disposed on the side of the angle grinding disc 22 close to the human body. This can effectively prevent debris from splashing onto the user, and can also prevent the angle grinding disc 22 from being accidentally damaged and splashing onto the user to cause injury to the user.

In some embodiments, the electric tool may further include: a circuit board assembly 24 and a heat sink (not shown in FIG. 8 ); the circuit board assembly 24 is provided with a controller or a signal processing device 15; and the heat sink is attached to the circuit board assembly 24. The signal processing device 15 and other power devices on the circuit board assembly 24 will generate a lot of heat when working. The circuit board assembly 24 is attached to the heat sink to effectively transfer the heat generated by the circuit board assembly 24.

Continuing to refer to FIG8 , in some embodiments, the electric tool may further include: a connecting component 25; the connecting component 25 is used to fix the circuit board assembly 24 to the housing 11. The circuit board assembly 24 is fixed to the threaded hole on the upper housing by the connecting component 25, such as a screw. Those skilled in the art can choose the fixing method by themselves. The present application does not limit the method of fixing the circuit board assembly 24 to the upper housing. There is no limitation on the position of the housing where the circuit board assembly 24 is fixed. Those skilled in the art can choose the upper housing, the lower housing, or other more suitable positions to enhance the strength of the electric tool, protect the circuit board assembly 24 and the signal processing device 15, reduce the disturbance of the signal processing device 15, and improve the accuracy of the control of the electric tool.

Continuing to refer to Figure 8, in some embodiments, the shell 11 may include an inlet 112 and an air outlet 113; the inlet 112 is arranged at a position of the shell 11 away from the motor; the air outlet is arranged on the side of the shell away from the air inlet. The inlet 112 is arranged at an end of the lower shell away from the motor. The air outlet 113 is arranged at an end of the upper shell away from the inlet 112. A fan may also be arranged in the shell. When the fan starts working, the air flow enters the shell 11 from the inlet 112, flows through the heat sink and then flows out from the air outlet 113, taking away most of the heat generated by the signal processing device during operation. It should be noted here that the present application does not limit the positions of the inlet 112 and the air outlet 113, and technicians in this field can design them by themselves.

Based on the same idea, the present application also provides a method for obtaining phase information of an AC signal, as shown in FIG9 , which is a flow chart of a method for obtaining phase information of an AC signal provided in an embodiment of the present application, wherein the AC signal is used to provide electric energy for an electric tool or an energy storage device, and is characterized in that the specific steps include:

Step S101: Process an alternating current signal through a phase shift module to obtain a first electrical signal and a second electrical signal.

Step S102: Process the first electrical signal and the second electrical signal through a phase-locked loop module to obtain phase information of the AC electrical signal; wherein the first electrical signal and the second electrical signal have the same amplitude and a phase angle difference of 90°.

The method for acquiring the phase information of the AC signal in this embodiment can be implemented by the electric tool provided by any embodiment of the present application, includes the technical features of the electric tool provided by any embodiment of the present application, and has the beneficial effects of the corresponding features, which will not be repeated here.

Note that the above are only preferred embodiments of the present application and the technical principles used. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present application. Therefore, although the present application is described in more detail through the above embodiments, the present application is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims (10)

1. An electric tool, comprising: case; A power input device, used to receive an AC signal to provide the power tool with the power required for operation; motor; A drive circuit, electrically connected to the motor; the drive circuit is used to drive the motor; a controller, electrically connected to the drive circuit, and configured to output a control signal to the drive circuit to control the operation of the motor; The signal processing device comprises a phase shift module; the phase shift module is used to convert the AC signal into a first electrical signal and a second electrical signal; the amplitudes of the first electrical signal and the second electrical signal are substantially the same, and the phase angles thereof are substantially different by 90°; the signal processing device is further used to obtain the phase information of the AC signal connected to the power input device according to the first electrical signal and the second electrical signal; The controller is configured to regulate the control signal based on the phase information. 2. The electric tool according to claim 1, characterized in that the phase shift module comprises a band pass filter and a first low pass filter; The phase shift module is used to filter out high-frequency interference signals and low-frequency interference signals from the AC signal through the bandpass filter to obtain a first electrical signal; the phase shift module is also used to filter out high-frequency interference signals from the AC signal through the first low-pass filter to obtain a second electrical signal. 3. The electric tool according to claim 1, characterized in that the signal processing device further comprises: a compensation module; The signal processing device is further used to remove the low-frequency interference signal and the DC bias signal of the second electrical signal through the compensation module to obtain a third electrical signal; The signal processing device is used to obtain the phase information of the AC electric signal according to the first electric signal and the third electric signal. 4. The electric tool according to claim 3, characterized in that the signal processing device further comprises: a feedback module; The feedback module is used to make a difference between the AC electric signal and the first electric signal, and output a first difference signal to the phase shift module, so that the phase shift module regulates the first electric signal and the second electric signal according to the first difference signal. 5. The electric tool according to claim 4, characterized in that the compensation module comprises a second low-pass filter; The compensation module is used for filtering the first difference signal through the second low-pass filter and then compensating the second electrical signal to obtain the third electrical signal. 6. The electric tool according to claim 1, characterized in that the signal processing device further comprises: a compensation module; the compensation module comprises a high pass filter; The compensation module is specifically used to remove low-frequency interference signals and DC bias signals from the AC signal through the high-pass filter to obtain a compensated AC signal; and convert the compensated AC signal into the first electrical signal and the second electrical signal through the phase shift module. 7. The electric tool according to claim 1, characterized in that the signal processing device also includes a phase-locked loop module; the phase-locked loop module is used to access the first electrical signal and the second electrical signal output by the phase shift module, and output phase information of the AC electrical signal. 8 . The electric tool according to claim 7 , wherein the phase-locked loop module comprises an orthogonal phase-locked loop or a DQ conversion module. 9. The electric tool according to claim 1, further comprising: a circuit board assembly and a heat sink; The circuit board assembly is provided with the controller or the signal processing device; the heat sink is attached to the circuit board assembly. 10. A method for acquiring phase information of an alternating current signal, wherein the alternating current signal is used to provide electric energy for an electric tool or an energy storage device, wherein the method comprises: Processing the alternating current signal through a phase shift module to obtain a first electrical signal and a second electrical signal that are orthogonal or substantially orthogonal; The first electrical signal and the second electrical signal are processed by a phase-locked loop module to obtain phase information of the AC electrical signal; wherein the first electrical signal and the second electrical signal have the same amplitude and a phase angle difference of substantially 90°.