Control type selsyn output voltage detection circuit

Abstract

The invention discloses a control type selsyn output voltage detection circuit, which relates to the technical field of voltage detection circuits, and comprises a power supply circuit for reducing an input 24V voltage into a constant 12V voltage for supplying power to an operational amplifier and outputting a + 5V precise reference voltage; the strong and weak current isolation conversion circuit is used for converting the tested alternating current signal into a low-voltage isolation signal; the zero-cross detection circuit is used for comparing the amplitude of the alternating-current voltage with the reference voltage and outputting a positive signal when the amplitude is lower than the reference voltage; the rectifying circuit is used for rectifying the input voltage and the signal output by the zero-cross detection circuit into a high level or a low level; the filtering and amplifying circuit filters the pulsating voltage output by the rectifying circuit, amplifies the pulsating voltage and then outputs the pulsating voltage; compared with the prior art, a special alternating current amplification servo motor does not need to be used, the circuit manufacturing cost is low, a single power source is used for supplying power, the output signal value is 1-9 V, signals can be remotely controlled, and a feedback system is compact in structure, high in universality and good in expansibility.

Description

Technical Field

[0001] The present invention relates to the technical field of voltage detection circuits, and specifically to an output voltage detection circuit for a control selsyn. Background Art

[0002] In a servo system, a combined system composed of a control selsyn and a servo mechanism is widely used at present because it can drive a relatively large load and has a high angle transmission accuracy. Its working principle is as Figure 1 shown. In Figure 1 , the exciting winding of the control selsyn transmitter is excited by a single-phase AC power supply, and its three-phase synchronizing windings are correspondingly connected to the synchronizing windings of the selsyn transformer. The output winding of the selsyn transformer is usually connected to the input end of an amplifier, and the output end of the amplifier is then connected to the control winding of the servo motor (as Figure 2 shown). In this way, the servo motor drives the load to rotate, and at the same time drives the rotor of the selsyn transformer through a speed reducer to form a mechanical feedback connection. When the rotor of the selsyn transformer deflects, the misalignment angle decreases, and the voltage signal of the output winding decreases until the coordination position

[0003] However, in the control circuit of the control selsyn, in the prior art, after the output signal is amplified by AC, a follow-up control is carried out by driving an AC servo motor. However, in the prior art, due to the large volume and high cost of the servo motor, remote control cannot be achieved. Summary of the Invention

[0004] The purpose of the present invention is to provide an output voltage detection circuit for a control selsyn to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: An output voltage detection circuit for a control selsyn, comprising:[[]]

[0006] A power supply circuit that steps down the input 24V voltage to a constant voltage of 12V to supply power to the operational amplifier and outputs a +5V precision reference voltage;

[0007] A strong-weak electricity isolation conversion circuit for converting the measured AC signal into a low-voltage isolation signal;

[0008] A zero-crossing detection circuit that compares the AC voltage amplitude with the reference voltage and outputs a positive signal when it is lower than the reference voltage;

[0009] A rectification circuit that rectifies the input voltage combined with the signal output by the zero-crossing detection circuit into a high level or a low level;

[0010] A filter amplification circuit that filters the pulsating voltage output by the rectification circuit and amplifies it before outputting.

[0011] Among them, the power supply circuit is composed of capacitor C1, capacitor C2, capacitor C3, capacitor C4, three-terminal voltage regulator U3, precision voltage-regulating diode D1, precision voltage-regulating diode D2, operational amplifier U2 / 2, and resistor R1;

[0012] After the DC 24V voltage is isolated by the precision voltage-regulating diode D1 and filtered by the capacitor C1, it is input to pin 1 of the three-terminal voltage regulator U3. Pin 2 of the three-terminal voltage regulator U3 is connected to the negative power supply, and pin 3 of the three-terminal voltage regulator U3 outputs 12V. After being filtered by the capacitors C2 and C3, it is connected to the VCC terminal, and the VCC terminal is connected to the power supply pin of the operational amplifier U2 / 2;

[0013] The VCC terminal is connected to the precision voltage-regulating diode D2 through the current-limiting resistor R1. The positive terminal of the precision voltage-regulating diode D2 is connected to the non-inverting input of the operational amplifier U2 / 2, and the inverting input is connected to the output terminal to form a voltage follower with negative feedback. The output terminal of the operational amplifier U2 / 2 outputs a reference +5V voltage, which serves as the virtual ground of the rectifying operational amplifier circuit.

[0014] Among them, the strong-weak electricity isolation conversion circuit is composed of miniature AC voltage transformer T1, miniature AC voltage transformer T2, current-limiting resistor R2, current-limiting resistor R12, sampling resistor R3, and sampling resistor R13;

[0015] The negative terminals of the secondaries of the miniature AC voltage transformer T1 and the miniature AC voltage transformer T2 are connected to the +5V reference voltage, and the turns ratio of the primary and secondary windings of the miniature AC voltage transformer T1 and the miniature AC voltage transformer T2 is equal, which is 1:1;

[0016] The calculation formula for the output and input voltages of the strong-weak electricity isolation conversion circuit is:

[0017] Uo = Ui * R3 / (R2 + R) + 5V

[0018] Among them, Uo is the output voltage, Ui is the input voltages ZKJ and ZKF, R2 is the value of the input current-limiting resistor, R is the resistance value of the miniature AC voltage transformer T1, and R3 is the resistance value of the sampling resistor R3;

[0019] Through the strong-weak electricity isolation conversion circuit, the AC voltages of ZKJ and ZKF of the control type synchro are isolated and converted into a sinusoidal voltage with an AC amplitude of 0 - 1.5V centered around the voltage +5V.

[0020] Among them, the zero-crossing detection circuit is composed of operational amplifier U2 / 1, resistor R14, resistor R15, and resistor R16;

[0021] When the operational amplifier U2 / 1 operates with the AC voltage amplitude compared with the reference voltage, the secondary of the miniature AC voltage transformer T2 is respectively connected to the non-inverting and inverting input terminals of the operational amplifier U2 / 1;

[0022] When the input ZKF AC voltage is in the positive half - cycle, the voltage at the non - inverting input terminal of the operational amplifier U2 / 1 is higher than that at the inverting input terminal. The operational amplifier U2 / 1 outputs a high level, which drives the MOS transistors Q1 and Q2 to conduct after being limited by the resistor R15;

[0023] When the input ZKF AC voltage is in the negative half - cycle, the voltage at the non - inverting input terminal of the operational amplifier U2 / 1 is lower than that at the inverting input terminal. The operational amplifier U2 / 1 outputs a low level, and the MOS transistors Q1 and Q2 are cut off.

[0024] Among them, the rectifier circuit consists of the operational amplifier U1 / 1, the resistors R4, R5, R6 and the MOS transistors Q1, Q2;

[0025] The resistors R4, R5, and R6 have equal resistance values. When the input ZKF AC voltage is in the positive half - cycle and the MOS transistors Q1 and Q2 are conducting, the non - inverting input terminal of the operational amplifier U1 / 1 is connected to the reference voltage +5V. The operational amplifier U1 / 1 operates in the inverting amplification region. Since R5 = R6, the output voltage Uo = 10 - input voltage Ui;

[0026] When the input ZKF AC voltage is in the negative half - cycle, the MOS transistors Q1 and Q2 are cut off. According to the principle of virtual short - circuit at the input terminals of the operational amplifier U1 / 1, the voltages at the non - inverting output terminal, inverting output terminal and output terminal of the operational amplifier U1 / 1 are equal, and the output voltage Uo = input voltage Ui.

[0027] Among them, the rectifier - filter - amplification circuit consists of the operational amplifier U1 / 2, the resistors R7, R8, R9, R10, R11, the capacitors C5 and C6;

[0028] Among them, the resistor R7 and the capacitor C5 form a first - order low - pass filter circuit, and the resistor R10 and the capacitor C6 form a second - order low - pass filter circuit;

[0029] The pulsating DC voltage signal output by the rectifier circuit operational amplifier U1 / 1 becomes a smooth DC voltage after low - pass filtering by the resistor R7 and the capacitor C5, and is output after being inversely amplified by the operational amplifier U1 / 2;

[0030] The output voltage Uo of the operational amplifier U1 / 2=(10 - Ui)*R10 / R8. By adjusting the resistance value of the resistor R10, the output voltage value reaches a maximum of 9V when the self - synchronizer misalignment angle is 90 degrees;

[0031] The relationship between the output voltage value Uo finally achieved by the rectifier - filter - amplification circuit and the misalignment angle θ is as follows:

[0032] Uo = sinθ*4 + 5.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] In the present invention, the AC voltage signal ZKJ output by the synchro and the AC voltage ZKF input to the synchro are input through a strong-weak electricity isolation conversion circuit. The zero-crossing detection circuit performs zero-crossing detection on the AC voltage ZKF, and outputs a positive control signal for the positive half-cycle voltage; the controllable rectification circuit rectifies the output voltage ZKJ of the synchro combined with the signal output by the zero-crossing detection circuit into a high level or a low level; the filtering and amplification circuit filters the pulsating voltage output by the rectification circuit and amplifies it to output a stable DC voltage signal, realizing the conversion of the misalignment angle difference of the control type synchro into a voltage signal between 1-9V. Compared with the prior art, there is no need to use a dedicated AC amplified servo motor, the circuit cost is low, it is powered by a single power supply, the output signal value is 1-9V, the signal can be remotely controlled, the feedback system has a compact structure, strong versatility, and good expandability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is the internal circuit structure diagram of the control type synchro of the prior art of the present invention;

[0036] Figure 2 is the control principle structure diagram of the control type synchro of the prior art of the present invention;

[0037] Figure 3 is the power supply circuit structure diagram of the present invention;

[0038] Figure 4 is the principle structure diagram of the strong-weak electricity isolation, zero-crossing detection, rectification, and filtering and amplification circuits of the present invention.

[0039] In the figure: 1. Synchro receiver; 2. Synchro transmitter; 3. Servo motor; 4. AC signal amplifier. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0041] Please refer to Figures 1-4 , this embodiment provides: A control type synchro output voltage detection circuit, including:

[0042] A power supply circuit that steps down the input 24V voltage to a constant voltage of 12V for powering the operational amplifier and outputs a +5V precision reference voltage;

[0043] A strong-weak electricity isolation conversion circuit is used to convert the measured AC signal into a low-voltage isolation signal;

[0044] A zero-crossing detection circuit compares the AC voltage amplitude with a reference voltage and outputs a positive signal when it is lower than the reference voltage;

[0045] A rectification circuit rectifies the input voltage combined with the signal output by the zero-crossing detection circuit into a high level or a low level;

[0046] A filtering and amplifying circuit filters the pulsating voltage output by the rectification circuit and amplifies it before outputting.

[0047] Among them, the working principle of the power supply circuit is as Figure 3 , and the power supply circuit consists of capacitor C1, capacitor C2, capacitor C3, capacitor C4, three-terminal voltage regulator U3, precision voltage stabilizing diode D1, precision voltage stabilizing diode D2, operational amplifier U2 / 2 and resistor R1;

[0048] After the DC 24V voltage is isolated by the precision voltage stabilizing diode D1 and filtered by the capacitor C1, it is input to pin 1 of the three-terminal voltage regulator U3. The 2nd pin of the three-terminal voltage regulator U3 is connected to the negative power supply. The 3rd pin of the three-terminal voltage regulator U3 outputs 12V, which is filtered by the capacitors C2 and C3 and then connected to the VCC terminal. The VCC terminal is connected to the power supply pin of the operational amplifier U2 / 2;

[0049] The VCC terminal is connected to the precision voltage stabilizing diode D2 through the resistor R1 for current limiting. The positive terminal of the precision voltage stabilizing diode D2 is connected to the non-inverting input of the operational amplifier U2 / 2, and the inverting input is connected to the output terminal to form a voltage follower with negative feedback. The output terminal of the operational amplifier U2 / 2 outputs a reference +5V voltage, which serves as the virtual ground of the rectification and operational amplification circuit.

[0050] Among them, the working principle of the strong-weak electricity isolation circuit is as Figure 4 , and the strong-weak electricity isolation conversion circuit consists of a micro AC voltage transformer T1, a micro AC voltage transformer T2, a current limiting resistor R2, a current limiting resistor R12, a sampling resistor R3 and a sampling resistor R13;

[0051] The negative terminals of the secondaries of the micro AC voltage transformer T1 and the micro AC voltage transformer T2 are connected to the +5V reference voltage, and the turns ratio of the primary and secondary windings of the micro AC voltage transformer T1 and the micro AC voltage transformer T2 is equal, which is 1:1;

[0052] The calculation formula for the output and input voltages of the strong-weak electricity isolation conversion circuit is:

[0053] Uo = Ui * R3 / (R2 + R) + 5V

[0054] Wherein, Uo is the output voltage, Ui is the input voltages ZKJ and ZKF, R2 is the value of the input current-limiting resistor, R is the resistance value of the micro AC voltage transformer T1, and R3 is the resistance value of the sampling resistor R3;

[0055] The AC voltages of ZKJ and ZKF of the control synchro are isolated and converted by the strong-weak electricity isolation conversion circuit into a sine voltage with an AC amplitude of 0 - 1.5V centered around the +5V voltage.

[0056] Among them, the working principle of the zero-crossing detection circuit is as Figure 4 , and the zero-crossing detection circuit consists of an operational amplifier U2 / 1, a resistor R14, a resistor R15, and a resistor R16;

[0057] When the operational amplifier U2 / 1 works with the AC voltage amplitude and the reference voltage, the secondary of the micro AC voltage transformer T2 is respectively connected to the in-phase and anti-phase input terminals of the operational amplifier U2 / 1;

[0058] When the input ZKF AC voltage is in the positive half-cycle, the voltage at the in-phase input terminal of the operational amplifier U2 / 1 is higher than that at the anti-phase terminal, and the operational amplifier U2 / 1 outputs a high level. After being current-limited by the resistor R15, it drives the MOS transistors Q1 and Q2 to conduct;

[0059] When the input ZKF AC voltage is in the negative half-cycle, the voltage at the in-phase input terminal of the operational amplifier U2 / 1 is lower than that at the anti-phase terminal, and the operational amplifier U2 / 1 outputs a low level, and the MOS transistors Q1 and Q2 are cut off.

[0060] Among them, the working principle of the rectification circuit is as Figure 4 , and the rectification circuit consists of an operational amplifier U1 / 1, a resistor R4, a resistor R5, a resistor R6, and MOS transistors Q1 and Q2;

[0061] The resistance values of the resistors R4, R5, and R6 are equal. When the input ZKF AC voltage is in the positive half-cycle and the MOS transistors Q1 and Q2 are conducting, the in-phase input terminal of the operational amplifier U1 / 1 is connected to the reference voltage +5V, and the operational amplifier U1 / 1 works in the inverting amplification region. Since R5 = R6, the output voltage Uo = 10 - the input voltage Ui;

[0062] When the input ZKF AC voltage is in the negative half-cycle and the MOS transistors Q1 and Q2 are cut off, according to the principle of virtual short at the input terminals of the operational amplifier U1 / 1, the voltages at the in-phase output terminal, anti-phase output terminal, and output terminal of the operational amplifier U1 / 1 are equal, and the output voltage Uo = the input voltage Ui;

[0063] If the output ZKJ voltage and the input ZKF voltage of the control synchro are in the same phase, when the positive half cycle of the input voltage of ZFJ occurs, ZKF is also in the positive half cycle, MOS transistors Q1 and Q2 are turned on, and Uo = 10 - input voltage Ui, converting the positive half cycle voltage into a negative voltage (relative to the 5V reference voltage);

[0064] When the negative half cycle of the input voltage of ZFJ occurs, ZKF is in the negative half cycle, MOS transistors Q1 and Q2 are turned off, the output voltage Uo = input voltage Ui, and the operational amplifier outputs a negative voltage (relative to the 5V reference voltage);

[0065] Therefore, when the ZKJ voltage and the ZKF voltage are in the same phase, the operational amplifier rectifies and outputs a negative pulsating DC voltage (relative to the 5V reference voltage), and the amplitude of the pulsation linearly varies with the amplitude of the ZKJ voltage.

[0066] When the output ZKJ voltage and the input ZKF voltage of the control synchro are in opposite phases, when the positive half cycle of the input voltage of ZFJ occurs, ZKF is in the negative half cycle, MOS transistors Q1 and Q2 are turned off, the output voltage Uo = input voltage Ui, and the operational amplifier outputs a positive voltage (relative to the 5V reference voltage); when the negative half cycle of the input voltage of ZFJ occurs, ZKF is in the positive half cycle, MOS transistors Q1 and Q2 are turned on, and Uo = 10 - input voltage Ui, converting the negative half cycle voltage into a positive voltage (relative to the 5V reference voltage); therefore, when the ZKJ voltage and the ZKF voltage are in opposite phases, the operational amplifier rectifies and outputs a positive pulsating DC voltage (relative to the 5V reference voltage), and the amplitude of the pulsation linearly varies with the amplitude of the ZKJ voltage.

[0067] Among them, the working principle of the rectifier filter amplifier circuit is as Figure 4 , and the rectifier filter amplifier circuit consists of operational amplifier U1 / 2, resistor R7, resistor R8, resistor R9, resistor R10, resistor R11, capacitor C5 and capacitor C6;

[0068] Among them, resistor R7 and capacitor C5 form a first-order low-pass filter circuit, and resistor R10 and capacitor C6 form a second-order low-pass filter circuit;

[0069] The pulsating DC voltage signal output by the rectifier circuit operational amplifier U1 / 1 becomes a smooth DC voltage after low-pass filtering by resistor R7 and capacitor C5, and is output after being inverted and amplified by operational amplifier U1 / 2;

[0070] The output voltage Uo of operational amplifier U1 / 2 = (10 - Ui) * R10 / R8. By adjusting the value of resistor R10, the output voltage value reaches a maximum of 9V when the synchro misalignment angle is 90 degrees;

[0071] The relationship between the finally achieved output voltage value Uo of the rectifier filter amplifier circuit and the misalignment angle θ is as follows:

[0072] Uo = sinθ * 4 + 5。

[0073] In summary: In the present invention, the AC voltage signal ZKJ output by the synchro and the AC voltage ZKF input to the synchro are input through a strong-weak electricity isolation conversion circuit. The zero-crossing detection circuit performs zero-crossing detection on the AC voltage ZKF, and outputs a positive control signal for the positive half-cycle voltage. The controlled rectifier circuit rectifies the output voltage ZKJ of the synchro combined with the signal output by the zero-crossing detection circuit into a high level or a low level. The filter amplification circuit filters the pulsating voltage output by the rectifier circuit and amplifies it to output a stable DC voltage signal, realizing the conversion of the misalignment angle difference of the control synchro into a voltage signal between 1 - 9V. Compared with the prior art, it does not require the use of a dedicated AC amplified servo motor, the circuit cost is relatively low, it uses a single power supply, the output signal value is 1 - 9V, the signal can be remotely controlled, the feedback system has a compact structure, strong versatility, and good expandability.

[0074] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0075] The above is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A controlled synchro output voltage detection circuit, characterized in that: include: The power supply circuit steps down the input 24V voltage to a constant 12V voltage to power the operational amplifier and outputs a +5V precision reference voltage; Strong and weak current isolation conversion circuit, used to convert the measured AC signal into a low-voltage isolation signal; The zero-crossing detection circuit compares the AC voltage amplitude with the reference voltage and outputs a positive signal when it is lower than the reference voltage; A rectifier circuit, which rectifies the input voltage combined with the signal output by the zero-crossing detection circuit into a high level or a low level; The filter amplifier circuit filters the pulsating voltage output by the rectifier circuit and outputs it after amplification.

2. The controlled synchro output voltage detection circuit according to claim 1, characterized in that: The power supply circuit is composed of capacitor C1, capacitor C2, capacitor C3, capacitor C4, three-terminal voltage regulator U3, precision voltage regulator diode D1, precision voltage regulator diode D2, operational amplifier U2 / 2 and resistor R1; The DC 24V voltage is isolated by the precision voltage regulator diode D1, filtered by the capacitor C1, and input to the input pin 1 of the three-terminal voltage regulator U3. The pin 2 of the three-terminal voltage regulator U3 is connected to the negative pole of the power supply. The pin 3 of the three-terminal voltage regulator U3 outputs 12V, which is filtered by the capacitors C2 and C3 and connected to the VCC terminal. The VCC terminal is connected to the power supply pin of the operational amplifier U2 / 2. The VCC terminal is connected to the precision voltage zener diode D2 through the current limiting resistor R1. The positive terminal of the precision voltage zener diode D2 is connected to the non-inverting input of the operational amplifier U2 / 2, and the inverting input is connected to the output terminal to form a negative feedback voltage follower. The output terminal of the operational amplifier U2 / 2 outputs the reference +5V voltage as the virtual ground of the rectifier operational amplifier circuit.

3. The controlled synchro output voltage detection circuit according to claim 1, characterized in that: The strong and weak current isolation conversion circuit is composed of a micro AC voltage transformer T1, a micro AC voltage transformer T2, a current limiting resistor R2, a current limiting resistor R12, a sampling resistor R3 and a sampling resistor R13; The negative terminals of the secondary of the micro AC voltage transformer T1 and the micro AC voltage transformer T2 are connected to a +5V reference voltage, and the primary and secondary turns ratio of the micro AC voltage transformer T1 and the micro AC voltage transformer T2 is equal to 1:1; The calculation formula for the output and input voltage of the strong and weak current isolation conversion circuit is: Uo=Ui*R3 / (R2+R)+5V Among them, Uo is the output voltage, Ui is the input voltage ZKJ and ZKF, R2 is the input current limiting resistance value, R is the resistance value of the micro AC voltage transformer T1, and R3 is the resistance value of the sampling resistor R3; The strong and weak current isolation conversion circuit is used to isolate and convert the AC voltage of ZKJ and ZKF of the controlled self-synchronous motor into a sinusoidal voltage with an AC amplitude of 0-1.5V around the center voltage +5V.

4. The controlled synchro output voltage detection circuit according to claim 1, characterized in that: The zero-crossing detection circuit is composed of an operational amplifier U2 / 1, a resistor R14, a resistor R15 and a resistor R16; When the operational amplifier U2 / 1 works at the AC voltage amplitude and the reference voltage, the secondary of the miniature AC voltage transformer T2 is connected to the in-phase and inverting input terminals of the operational amplifier U2 / 1 respectively; When the input ZKF AC voltage is in the positive half cycle, the voltage at the in-phase input terminal of the operational amplifier U2 / 1 is higher than the voltage at the inverting terminal, and the operational amplifier U2 / 1 outputs a high level, which drives the MOS tubes Q1 and Q2 to turn on after the resistor R15 limits the current. When the input ZKF AC voltage is in the negative half cycle, the voltage at the non-inverting input terminal of the operational amplifier U2 / 1 is lower than the voltage at the inverting terminal, the operational amplifier U2 / 1 outputs a low level, and the MOS tubes Q1 and Q2 are cut off.

5. The controlled synchro output voltage detection circuit according to claim 1, characterized in that: The rectifier circuit is composed of an operational amplifier U1 / 1, a resistor R4, a resistor R5, a resistor R6 and MOS tubes Q1 and Q2; The resistance values ​​of resistors R4, R5 and R6 are equal. When the input ZKF AC voltage is in the positive half cycle, MOS tubes Q1 and Q2 are turned on, the in-phase input terminal of the operational amplifier U1 / 1 is turned on with the reference voltage +5V, and the operational amplifier U1 / 1 works in the inverting amplification area. Because R5=R6, the output voltage Uo=10-input voltage Ui; When the input ZKF AC voltage is in the negative half cycle, MOS tubes Q1 and Q2 are cut off. According to the principle of virtual short at the input end of operational amplifier U1 / 1, the phase voltages of the in-phase output end, the inverting output end and the output end of operational amplifier U1 / 1 are equal, and the output voltage Uo = input voltage Ui.

6. The controlled synchro output voltage detection circuit according to claim 1, characterized in that: The rectifier filter amplifier circuit is composed of an operational amplifier U1 / 2, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a capacitor C5 and a capacitor C6; Among them, the resistor R7 and the capacitor C5 form a first-order low-pass filter circuit, and the resistor R10 and the capacitor C6 form a second-order low-pass filter circuit; The pulsating DC voltage signal output by the rectifier circuit operational amplifier U1 / 1 is low-pass filtered by resistor R7 and capacitor C5 to become a smooth DC voltage, which is then inverted and amplified by the operational amplifier U1 / 2 and then output; The output voltage Uo of the operational amplifier U1 / 2 is (10-Ui)*R10 / R8. By adjusting the resistance value of the resistor R10, the output voltage value is set to a maximum value of 9V when the synchro misalignment angle is 90 degrees. The relationship between the output voltage value Uo and the misalignment angle θ finally achieved by the rectifier filter amplifier circuit is as follows: Uo=sinθ*4+5.

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