A method for unidirectional current detection of a power tube

Abstract

The present application relates to the technical field of current signal processing, and discloses a one-way current detection method of a power tube, wherein the power detection part and the common-mode signal extraction unit are used to process power signals respectively to obtain power detection signals and common-mode detection signals, the power detection signals and the common-mode detection signals are subjected to bias voltage superposition respectively to obtain first detection signals and second detection signals, the first signal processing module and the second signal processing module are used to process the first detection signals and the second detection signals respectively to obtain voltage feedback signals having a fixed proportional relationship with one-way current signals, the technical scheme improves the precision and stability of current detection, effectively suppresses common-mode noise, enhances the reliability of signal processing, and realizes accurate control through voltage feedback with a fixed proportional relationship, thereby solving the problem of high cost of external resistance for detecting a circuit in the prior art.

Description

Technical Field

[0001] This invention relates to the field of current signal processing technology, and more particularly to a method for detecting unidirectional current in a power transistor. Background Technology

[0002] In the field of power electronics, accurate current detection and control are crucial for the performance and safe operation of equipment. In the existing technology, motor current detection generally adopts the external resistor method. Other similar on-chip detection methods are not easy to provide corresponding detection outputs. The external resistor method has a correspondingly high application cost. Other detection methods can only provide overcurrent protection due to insufficient accuracy and are not easy to provide a flag output. Summary of the Invention

[0003] The purpose of this invention is to provide a method for detecting the unidirectional current of a power transistor, which aims to solve the problem of high cost in the prior art of using an external resistor to detect the circuit.

[0004] The present invention is implemented as follows: Firstly, the present invention provides a method for detecting unidirectional current of a power transistor, comprising:

[0005] The unidirectional current signal of the power transistor is acquired, and the unidirectional current signal is processed by the power detection part and the common mode signal extraction unit, which are electrically connected to the power transistor, to obtain the power detection signal and the common mode detection signal.

[0006] The power detection signal and the common-mode detection signal are respectively superimposed with a bias voltage to obtain a first detection signal and a second detection signal;

[0007] The first detection signal and the second detection signal are processed by a first signal processing module electrically connected to the power detection section and a second signal processing module electrically connected to the common-mode signal extraction unit to obtain a voltage feedback signal; wherein the voltage feedback signal has a fixed proportional relationship with the unidirectional current signal.

[0008] This invention provides a method for detecting unidirectional current in a power transistor, which has the following advantages:

[0009] The application processes the power signal through the power detection part and the common mode signal extraction unit respectively to obtain the power detection signal and the common mode detection signal, superimposes the bias voltage on the power detection signal and the common mode detection signal respectively to obtain the first detection signal and the second detection signal, processes the first detection signal and the second detection signal through the first signal processing module and the second signal processing module respectively to obtain the voltage feedback signal having the fixed proportional relationship with the unidirectional current signal, and the technical scheme improves the precision and stability of current detection, effectively suppresses the common mode noise, enhances the reliability of signal processing, realizes accurate control through the voltage feedback of the fixed proportional relationship, and solves the problem of high cost of external resistance for detecting the circuit in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is a step schematic diagram of a unidirectional current detection method of a power tube provided by an embodiment of the application.

[0011] Figure 2 is a structural schematic diagram of a circuit used in a unidirectional current detection method of a power tube provided by an embodiment of the application. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical scheme and advantages of the application more clear, the application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and do not limit the application.

[0013] The implementation of the application is described in detail below in combination with specific embodiments.

[0014] Referring to Figure 1 , Figure 2 , a preferred embodiment provided by the application is shown.

[0015] In a first aspect, the application provides a unidirectional current detection method of a power tube, comprising:

[0016] S1: obtaining a unidirectional current signal of a power tube, and processing the unidirectional current signal through a power detection part and a common mode signal extraction unit electrically connected to the power tube respectively to obtain a power detection signal and a common mode detection signal;

[0017] S2: superimposing bias voltage on the power detection signal and the common mode detection signal respectively to obtain a first detection signal and a second detection signal;

[0018] S3: performing signal processing on the first detection signal and the second detection signal by a first signal processing module electrically connected with the power detection part and a second signal processing module electrically connected with the common-mode signal extraction unit, to obtain a voltage feedback signal; wherein the voltage feedback signal has a fixed proportional relationship with the unidirectional current signal.

[0019] Specifically, in step S1 of the embodiments provided in the present application, the unidirectional current signal is obtained from the power tube. The way to obtain the current signal is to electrically connect the detection circuit with the target power tube, so as to introduce the unidirectional current signal of the power tube.

[0020] It should be noted that the unidirectional current signal means that the current only flows in one direction (for example, from the power supply to the load). Such a signal can be direct current (DC) or alternating current (AC) but has unidirectional property.

[0021] More specifically, the obtained unidirectional current signal is sent to two different circuit units respectively. The power detection part is specially used for processing the effective component in the current signal, to extract the useful detection signal. The common-mode signal extraction unit is used for extracting the common-mode component in the current signal, so as to be compensated or corrected subsequently.

[0022] More specifically, the signal processing of the power detection part can include signal processing operations such as filtering, amplification, rectification, etc., to extract the effective component representing the current signal, to obtain the power detection signal. The power detection signal reflects the effective value or characteristic of the current.

[0023] More specifically, the common-mode signal extraction unit processing focuses on extracting the common-mode component in the current signal. These components are usually noise or interference. The common-mode detection signal contains the common-mode noise or interference component in the current signal.

[0024] It can be understood that by extracting the effective signal and the common-mode signal respectively, the useful signal and the noise can be effectively separated, and the quality and accuracy of the signal can be improved. The common-mode signal extraction unit can detect and identify the common-mode noise, which provides a basis for subsequent noise suppression. The power detection signal obtained by the power detection part can accurately reflect the actual situation of the current signal, and improve the measurement accuracy. The common-mode detection signal obtained by the common-mode signal extraction unit can be used for subsequent signal correction and compensation, and further improve the accuracy of signal processing.

[0025] Specifically, in step S2 of the embodiments provided in the present application, the power detection signal obtained from S1 is the power detection signal representing the effective component of the current signal. The common-mode detection signal obtained from S1 is the common-mode detection signal representing the common-mode noise or interference component in the current signal.

[0026] More specifically, the appropriate bias voltage is generated by a precision voltage source or a regulated resistance network, ensuring the stability and precision of the bias voltage, and the bias voltage is superimposed on the power detection signal to form the first detection signal, which can be achieved by an operational amplifier or an addition circuit. The bias voltage is superimposed on the common-mode detection signal to form the second detection signal, which can also be achieved by an operational amplifier or an addition circuit.

[0027] More specifically, the first detection signal is the signal after the bias voltage superposition processing, containing the power detection signal and the bias voltage. The signal after the bias voltage superposition processing contains the common-mode detection signal and the bias voltage.

[0028] It can be understood that by superimposing the appropriate bias voltage, the reference level of the signal can be effectively adjusted, making the subsequent signal processing more accurate and stable. The superposition of the bias voltage helps to adjust the signal to the appropriate working range, avoiding distortion or noise interference of the signal at low level. The detection signal after the bias voltage processing has higher stability, reduces the influence caused by environmental changes or power fluctuations, and provides stable and reliable input signals for the subsequent signal processing unit, which helps to improve the stability and reliability of the whole system.

[0029] It can be seen that the key of this step is to obtain the power detection signal and the common-mode detection signal obtained from step S1, and superimpose appropriate bias voltages respectively to form the first detection signal and the second detection signal. This processing method can effectively adjust the reference level of the signal, improve the precision and stability of the signal processing, and expand the dynamic range of the signal, providing more stable and reliable input signals for subsequent signal processing. This provides an important guarantee for the overall performance improvement and signal processing optimization of the system.

[0030] Specifically, in step S3 of the embodiments provided by the present application, the first detection signal obtained from step S2 is input into the first signal processing module, and the second detection signal obtained from step S2 is input into the second signal processing module.

[0031] More specifically, the first detection signal is filtered to remove high-frequency noise and unnecessary interference components, and the filtered signal is amplified to enhance the strength of the signal and ensure the usability of the signal. The amplified analog signal is converted into a voltage signal suitable for subsequent processing.

[0032] More specifically, the second detection signal is filtered to remove high-frequency noise and unnecessary interference components, and the filtered signal is amplified to enhance the strength of the signal.

[0033] More specifically, the signals output by the first signal processing module and the second signal processing module are combined to obtain a comprehensive voltage signal, and the combined voltage signal is adjusted according to system design requirements to have a fixed proportional relationship with the unidirectional current signal, which can be achieved by adjusting the gain, scaling, etc.

[0034] More specifically, the adjusted signal is output as a voltage feedback signal, which maintains a fixed proportional relationship with the unidirectional current signal, and the generated voltage feedback signal can be fed back to the control unit or other related modules of the system for further control and adjustment.

[0035] It can be understood that through filtering, amplification and conversion processing, the accuracy of the signal can be effectively improved, and the influence of noise and interference on the signal can be reduced, and the processed signal has higher stability, which helps the stable operation of the system. The fixed proportional feedback signal provides a reliable feedback mechanism, so that the system can timely adjust and optimize its performance.

[0036] Referring to Figure 2 , transistor Q5 is the sense tube of power tube Q1, in order to make the detection operational amplifier work in a suitable area, a suitable voltage Voffset is superimposed on the input, this additional error will be included in the common-mode current and subtracted, finally the output is a voltage based on zero level and proportional to Q1 current.

[0037] The present application provides a unidirectional current detection method for power tube, which has the following beneficial effects:

[0038] The present application processes power signals through power detection part and common-mode signal extraction unit respectively to obtain power detection signal and common-mode detection signal, superimposes bias voltage on power detection signal and common-mode detection signal respectively to obtain first detection signal and second detection signal, and uses first signal processing module and second signal processing module to process first detection signal and second detection signal respectively to obtain voltage feedback signal with fixed proportional relationship with unidirectional current signal. The technical scheme improves the precision and stability of current detection, effectively suppresses common-mode noise, enhances the reliability of signal processing, realizes accurate control through voltage feedback with fixed proportional relationship, and solves the problem of high cost of detecting circuit by using external resistance in the prior art.

[0039] It can be seen that the technical scheme of the application has a reasonable common-mode bias structure, realizes current-mode conversion output, has a common-mode current adjusting structure, and has the further advantages that high linearity can be achieved in low and high current detection, sensitivity to temperature and overall deviation is extremely low, various adaptive deviations can be flexibly adjusted, and the detection output mode can be flexibly applied to other applications.

[0040] Preferably, the step of superimposing bias voltage on the power detection signal and the common-mode detection signal to obtain the first detection signal and the second detection signal respectively comprises:

[0041] S21: superimposing bias voltage on the power detection signal through a first voltage source V1 pre-set between the power detection part and the first signal processing module to obtain a first detection signal; wherein the first voltage source V1 is used to provide bias voltage to the power detection signal for bias compensation, so that the power detection signal is in a signal region suitable for detection and operational work;

[0042] S22: superimposing bias voltage on the common-mode detection signal through a second voltage source V2 pre-set between the common-mode signal extraction unit and the second signal processing module to obtain a second detection signal; wherein the second voltage source V2 is used to provide bias voltage to the common-mode detection signal for bias compensation, so that the common-mode detection signal is in a signal region suitable for detection and operational work.

[0043] Specifically, the first voltage source V1 is pre-set between the power detection part and the first signal processing module, the first voltage source V1 is configured to ensure that it can provide appropriate bias voltage, the power detection signal is superimposed with the preset bias voltage through the first voltage source V1, the power detection signal is adjusted to a signal region suitable for detection and operational work through superimposition of bias voltage, and the signal after bias voltage adjustment is input to the first signal processing module as the first detection signal.

[0044] More specifically, the second voltage source V2 is pre-set between the common-mode signal extraction unit and the second signal processing module, the second voltage source V2 is configured to ensure that it can provide appropriate bias voltage, the common-mode detection signal is superimposed with the preset bias voltage through the second voltage source V2, the common-mode detection signal is adjusted to a signal region suitable for detection and operational work through superimposition of bias voltage, and the signal after bias voltage adjustment is input to the second signal processing module as the second detection signal.

[0045] It can be understood that by superimposing the bias voltage on the power detection signal and the common-mode detection signal respectively, it can be ensured that both signals are in a signal region suitable for detecting the operation of the operational amplifier, which is crucial for subsequent signal processing and can improve the accuracy and stability of signal processing. By bias compensation, the offset of the signal can be effectively eliminated, the reference position of the signal is more stable, and the error caused by signal offset is reduced.

[0046] Preferably, the step of signal processing the first detection signal and the second detection signal to obtain a voltage feedback signal by the first signal processing module electrically connected with the power detection part and the second signal processing module electrically connected with the common-mode signal extraction unit comprises:

[0047] S31: signal processing the first detection signal by the first signal processing module electrically connected with the power detection part to obtain a first feedback signal;

[0048] S32: signal processing the second detection signal by the second signal processing module electrically connected with the common-mode signal extraction unit to obtain a second feedback signal;

[0049] S33: signal synthesis processing the first feedback signal and the second feedback signal by the first signal processing module and the second signal processing module to make the second feedback signal perform bias voltage suppression processing on the first feedback signal, thereby obtaining a voltage feedback signal.

[0050] Specifically, the first signal processing module receives the first detection signal from the power detection part, performs amplification processing to improve the signal strength, removes high-frequency noise and interference in the signal through a filter to ensure the purity of the signal, performs shaping processing on the signal to make the signal waveform more regular and stable, converts the analog signal into a digital signal for subsequent digital signal processing.

[0051] More specifically, the second signal processing module electrically connected with the common-mode signal extraction unit processes the second detection signal to obtain a second feedback signal. The second signal processing module receives the second detection signal from the common-mode signal extraction unit, extracts the common-mode signal component therein, applies common-mode noise suppression technology to filter out common-mode noise, improves the signal-to-noise ratio of the signal, amplifies the processed signal to ensure sufficient signal strength, and converts the processed signal from analog form to digital form for subsequent processing.

[0052] More specifically, by the first signal processing module and the second signal processing module are electrically connected, the first feedback signal and the second feedback signal are signal synthesis processing, so that the second feedback signal to the first feedback signal offset voltage inhibition processing, to obtain the voltage feedback signal, the first feedback signal and the second feedback signal are synthesized, usually using the method of superposition or weighted average, using the common mode information in the second feedback signal, the bias voltage in the first feedback signal is inhibited, the bias error is reduced, and the processed synthesis signal is output as the voltage feedback signal for subsequent control system.

[0053] It can be understood that by the respective processing and synthesis of the first signal processing module and the second signal processing module, the bias voltage can be effectively extracted and inhibited, the accuracy of the feedback signal is improved, the common mode noise in the feedback signal is significantly reduced by the common mode signal extraction and noise suppression technology, the purity of the signal is improved, and the stable and reliable voltage feedback signal helps the accurate adjustment of the control system and improves the stability and response speed of the entire system.

[0054] Preferably, the first signal processing module and the second signal processing module each include a detection signal amplification part, a detection signal current conversion part, and a current synthesis unit.

[0055] Specifically, the first signal processing module and the second signal processing module have the same components, and the first signal processing module and the second signal processing module perform the same processing effect.

[0056] Preferably, the step of signal processing of the first detection signal by the first signal processing module electrically connected with the power detection part to obtain the first feedback signal comprises:

[0057] S311: Signal amplification processing of the first detection signal by the detection signal amplification part to obtain a first amplified signal;

[0058] S312: Current conversion processing of the first amplified signal by the detection signal current conversion part to obtain a first feedback signal, for signal synthesis processing of the first feedback signal and the second feedback signal by the current synthesis unit.

[0059] Specifically, the first signal processing module receives the first detection signal from the power detection part, first amplifies the signal by the detection signal amplification part to enhance the signal strength, and the amplified first detection signal is sent to the detection signal current conversion part to convert the voltage signal into a current signal for subsequent processing. The current signal is synthesized with other processed signals by the current synthesis unit to obtain the first feedback signal.

[0060] Preferably, the step of obtaining the second feedback signal by signal processing the second detection signal through the second signal processing module electrically connected with the common-mode signal extraction unit comprises:

[0061] S321: signal amplification processing the second detection signal through the detection signal amplification part to obtain a second amplified signal;

[0062] S322: current conversion processing the second amplified signal through the detection signal current conversion part to obtain a second feedback signal for the current synthesis unit to perform signal synthesis processing on the second feedback signal and the first feedback signal.

[0063] Specifically, the second signal processing module receives the second detection signal from the common-mode signal extraction unit, first amplifies the signal through the detection signal amplification part to enhance the signal strength, and sends the amplified second detection signal to the detection signal current conversion part to convert the voltage signal into a current signal for subsequent processing. The current signal is synthesized with other processed signals through the current synthesis unit to obtain the second feedback signal.

[0064] More specifically, the current synthesis unit of the first signal processing module synthesizes the first feedback signal with the second feedback signal output by the current synthesis unit of the second signal processing module. Through the synthesis processing, the bias voltage in the first feedback signal is suppressed by using the common-mode information in the second feedback signal, reducing the bias error. The synthesized current signal is converted back to a voltage signal, and finally a stable voltage feedback signal is output for subsequent control system.

[0065] Preferably, the power detection part comprises a power tube Q1, a transistor Q2 and a transistor Q3; the power tube Q1 is used to inject a unidirectional current signal, and the power tube Q1 is grounded; the transistor Q2 and the transistor Q3 are respectively electrically connected with the power tube Q1 in series, and the transistor Q2 and the transistor Q3 are in parallel state and electrically connected with the first signal processing module; the common-mode signal extraction unit comprises a transistor Q9, and the transistor Q9 is electrically connected with the power tube Q1.

[0066] Specifically, the power tube Q1 is used to inject a unidirectional current signal and is grounded, the transistor Q2 is connected in series with Q1, the transistor Q3 is connected in series with Q1, and Q2 and Q3 are in parallel state.

[0067] More specifically, the Power tube Q1 injects a unidirectional current signal, ensures the directionality and stability of the signal, and provides a stable reference potential to the ground. The transistors Q2 and Q3 are connected in series with Q1 and in parallel with each other, forming a signal processing channel for the regulation and amplification of the current signal. The parallel structure of Q2 and Q3 can achieve signal shunting and redundancy, ensuring the reliability and stability of signal processing.

[0068] More specifically, the common-mode signal extraction unit is composed of a transistor Q9, which is electrically connected to the Power tube Q1. The transistor Q9 is responsible for extracting the common-mode signal, and through the connection with Q1, it can effectively obtain the common-mode noise and interference signals in the system, providing the necessary common-mode information for the subsequent signal processing module.

[0069] More specifically, the Power tube Q1 injects a unidirectional current signal, and the ground forms a stable current path. The injected current signal is processed by the series-connected transistors Q2 and Q3, and Q2 and Q3 are connected in parallel to ensure the stability and shunting of the signal.

[0070] More specifically, the transistor Q9 is electrically connected to the Power tube Q1. Through this connection, Q9 can extract the common-mode signal in the system from Q1, providing common-mode information.

[0071] More specifically, the first signal processing module receives signals from the Power detection part, processes them through the detection signal amplification part, the detection signal current conversion part, and the current synthesis unit, and generates the first feedback signal. The detection signal amplification part enhances the signal, the current conversion part converts the voltage signal to a current signal, and the current synthesis unit performs synthesis processing on the signal.

[0072] More specifically, the second signal processing module receives signals from the common-mode signal extraction unit (through transistor Q9) and generates the second feedback signal after similar processing. The detection signal amplification part enhances the common-mode signal, the current conversion part converts the voltage signal to a current signal, and the current synthesis unit performs synthesis processing on the signal.

[0073] More specifically, the output signals of the first signal processing module and the second signal processing module are synthesized. During the synthesis process, the common-mode information in the second feedback signal is used to suppress the bias voltage in the first feedback signal, reducing the bias error. Finally, the synthesized signal is converted back to a voltage signal, and a stable voltage feedback signal is output.

[0074] It can be understood that the signal processing accuracy is effectively improved by detecting signal amplification and current conversion, the common-mode signal extraction unit is introduced to significantly reduce the noise interference in the system, the bias voltage is suppressed by the processing of the current synthesis unit, the system error is reduced, the stable and accurate voltage feedback signal improves the stability and response speed of the control system.

[0075] Preferably, the detection signal amplification part is an operational amplifier circuit composed of an operational amplifier Δ1, a resistor R1 and a resistor R2, and the detection signal current conversion part includes an operational amplifier Δ2, a transistor Q4 and a transistor Q5; the input end of the operational amplifier Δ2 is electrically connected with the transistor Q4, the positive input end of the operational amplifier Δ2 is electrically connected with the output end of the operational amplifier Δ1, and the inverting input end of the operational amplifier Δ2 is electrically connected with the transistor Q5; the transistor Q5 of the first signal processing module is electrically connected with the transistor Q5 of the second signal processing module; the current synthesis unit includes a transistor Q7 and a transistor Q8; the transistor Q7 of the first signal processing module is electrically connected with the transistor Q8 of the second signal processing module; the transistor Q8 of the first signal processing module is electrically connected with an external resistor and then grounded.

[0076] Specifically, the operational amplifier Δ1 is a core amplification device, the resistor R1 and the resistor R2 constitute an operational amplifier circuit with Δ1, and the circuit composed of the operational amplifier Δ1, the resistor R1 and the resistor R2 is used for amplifying the detection signal to ensure the strength and quality of the signal in subsequent processing.

[0077] More specifically, the element composition of the detection signal current conversion part includes an operational amplifier Δ2 for current conversion, a transistor Q4 connected with the input end of Δ2, and a transistor Q5 connected with the reverse input end of Δ2.

[0078] More specifically, the input end of the operational amplifier Δ2 is electrically connected with the transistor Q4, the positive input end is electrically connected with the output end of the operational amplifier Δ1, and the inverting input end is electrically connected with the transistor Q5, which is used for converting the amplified voltage signal into a current signal for subsequent processing.

[0079] More specifically, the element composition of the current synthesis unit includes a transistor Q7 and a transistor Q8, and the transistors Q7 and Q8 constitute a current synthesis unit for synthesizing the current signals from the first and second signal processing modules and converting the synthesized signals back to voltage signals.

[0080] More specifically, the input detection signal is first amplified by operational amplifier △1, resistors R1 and R2 provide necessary filtering and stabilization functions during amplification, the amplified signal is transmitted to △2 through the positive input terminal of operational amplifier △2, the input terminal of △2 is electrically connected with transistor Q4, the inverting input terminal is electrically connected with transistor Q5, and the voltage signal is converted into a current signal through operational amplifier △2.

[0081] More specifically, the transistor Q5 of the first signal processing module and the second signal processing module are electrically connected, ensuring the cooperative processing of the signals of the two modules, the current signals are synthesized through transistors Q7 and Q8, Q8 is electrically connected with an external resistor and then grounded, forming a complete signal processing loop, the synthesized current signals are converted back into voltage signals through transistors Q7 and Q8, a stable voltage feedback signal is output, and precise control and feedback are realized.

[0082] It can be understood that the combination of operational amplifiers and resistors ensures the high precision and stability of signal amplification, the process of converting voltage signals into current signals is precisely controlled, ensuring accurate signal transmission, common-mode signal extraction and processing effectively suppress common-mode noise and interference in the system, improving signal quality, the current synthesis unit synthesizes current signals from different signal processing modules through the cooperative work of transistors Q7 and Q8, and the finally output voltage signal is processed through synthesis, bias voltage is suppressed, and high-precision voltage feedback is realized.

[0083] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method of unidirectional current detection for a power tube, characterized by, The method comprises the following steps: obtaining a unidirectional current signal of a power tube, and performing signal processing on the unidirectional current signal through a power detection part and a common-mode signal extraction unit electrically connected to the power tube to obtain a power detection signal and a common-mode detection signal; superimposing bias voltages on the power detection signal and the common-mode detection signal to obtain a first detection signal and a second detection signal; performing signal processing on the first detection signal and the second detection signal through a first signal processing module electrically connected to the power detection part and a second signal processing module electrically connected to the common-mode signal extraction unit to obtain a voltage feedback signal; wherein the voltage feedback signal has a fixed proportional relationship with the unidirectional current signal; wherein the step of performing signal processing on the first detection signal and the second detection signal through the first signal processing module electrically connected to the power detection part and the second signal processing module electrically connected to the common-mode signal extraction unit to obtain a voltage feedback signal comprises: performing signal processing on the first detection signal through the first signal processing module electrically connected to the power detection part to obtain a first feedback signal; performing signal processing on the second detection signal through the second signal processing module electrically connected to the common-mode signal extraction unit to obtain a second feedback signal; performing signal synthesis processing on the first feedback signal and the second feedback signal through the electrical connection between the first signal processing module and the second signal processing module to enable the second feedback signal to perform bias voltage suppression processing on the first feedback signal, thereby obtaining a voltage feedback signal; the first signal processing module and the second signal processing module each comprise a detection signal amplification part, a detection signal current conversion part, and a current synthesis unit, the current synthesis unit of the first signal processing module is electrically connected to the current synthesis unit of the second signal processing module to synthesize the first feedback signal and the second feedback signal; the step of performing signal processing on the first detection signal through the first signal processing module electrically connected to the power detection part to obtain a first feedback signal comprises: performing signal amplification processing on the first detection signal through the detection signal amplification part to obtain a first amplified signal; performing current conversion processing on the first amplified signal through the detection signal current conversion part to obtain a first feedback signal, so that the current synthesis unit can perform signal synthesis processing on the first feedback signal and the second feedback signal; the step of performing signal processing on the second detection signal through the second signal processing module electrically connected to the common-mode signal extraction unit to obtain a second feedback signal comprises: performing signal amplification processing on the second detection signal through the detection signal amplification part to obtain a second amplified signal; performing current conversion processing on the second amplified signal through the detection signal current conversion part to obtain a second feedback signal, so that the current synthesis unit can perform signal synthesis processing on the second feedback signal and the first feedback signal.

2. A method of unidirectional current detection for a power tube as defined in claim 1, wherein, The step of superimposing bias voltage to the power detection signal and the common-mode detection signal respectively to obtain the first detection signal and the second detection signal comprises: The first detection signal is obtained by superimposing bias voltage to the power detection signal through a first voltage source V1 arranged in advance between the power detection part and the first signal processing module; wherein the first voltage source V1 is used to provide bias voltage to the power detection signal for bias compensation, so that the power detection signal is in a signal region suitable for detection of operational amplifier operation; The second detection signal is obtained by superimposing bias voltage to the common-mode detection signal through a second voltage source V2 arranged in advance between the common-mode signal extraction unit and the second signal processing module; wherein the second voltage source V2 is used to provide bias voltage to the common-mode detection signal for bias compensation, so that the common-mode detection signal is in a signal region suitable for detection of operational amplifier operation.

3. The method of claim 1, wherein the power tube is a triode thyristor (TRIAC). The power detection part comprises a power tube Q1, a transistor Q2 and a transistor Q3; The D port of the power tube Q1 is used to inject a unidirectional current signal, and the S port of the power tube Q1 is grounded; The D port of the transistor Q2 and the S port of the transistor Q3 are respectively connected in series with the D port and the S port of the power tube Q1, and the transistor Q2 and the transistor Q3 are connected in parallel with the first signal processing module; The common-mode signal extraction unit comprises a transistor Q9, and the S port of the transistor Q9 is connected with the power tube Q1.

4. The method of claim 1, wherein the power tube is a triode thyristor (TRIAC). The detection signal amplification part is an operational amplifier circuit composed of an operational amplifier Δ1, a resistor R1 and a resistor R2, and the detection signal current conversion part comprises an operational amplifier Δ2, a transistor Q4 and a transistor Q5; The output end of the operational amplifier Δ2 is connected with the G port of the transistor Q4, the positive input end of the operational amplifier Δ2 is connected with the output end of the operational amplifier Δ1, and the inverting input end of the operational amplifier Δ2 is connected with the D port of the transistor Q5; The S port of the transistor Q5 of the first signal processing module is connected with the S port of the transistor Q5 of the second signal processing module; The current synthesis unit comprises a transistor Q7 and a transistor Q8; The G port of the transistor Q7 of the first signal processing module is connected with the G port of the transistor Q8 of the second signal processing module; The S port of the transistor Q8 of the first signal processing module is connected with an external resistor and then grounded.

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