Voice coil motor driving circuit

Abstract

According to the voice coil motor driving circuit provided by the invention, a double-ring structure of a position ring and a current ring is designed, proportional-integral adjustment and phase advance adjustment are combined, and compared with a traditional three-ring structure, the following error of a slope instruction is eliminated, and the trajectory tracking precision and the dynamic response performance are optimized.

Description

Technical Field

[0001] The present application relates to the technical field of servo control, and in particular to a voice coil motor driving circuit. Background Art

[0002] Voice coil motors can achieve short-stroke linear motion control and are often used in semiconductor equipment, optical systems and other fields. They have high requirements for positioning accuracy, response performance and trajectory tracking performance.

[0003] At present, the P-PI-PI three-loop controller is often used in the control structure of voice coil motors. The three-loop control has strong stability, but the speed link introduces an inertial delay link to the system, which is not conducive to the dynamic response performance and trajectory tracking performance of the system. This three-loop structure has a steady-state error under the ramp position command, and it is difficult to meet the needs in some application scenarios with high response performance requirements.

[0004] In this regard, speed feedforward is usually added to the three-loop structure to optimize response performance and trajectory tracking accuracy. However, feedforward requires differentiation of the position command, which will amplify the noise in the position command. In addition, in actual applications, speed feedforward is prone to overshoot and affects system stability. The trajectory tracking accuracy is sensitive to the feedforward coefficient, which will increase the complexity of system tuning. Summary of the invention

[0005] The present application relates to a voice coil motor driving circuit, which can eliminate the following error of a ramp instruction and optimize trajectory tracking accuracy and dynamic response performance.

[0006] A voice coil motor driving circuit, comprising:

[0007] A subtractor module, used for receiving a position input signal and a position feedback signal, and performing subtraction processing on the position input signal and the position feedback signal to obtain a position error signal;

[0008] The position loop proportional-integral adjustment module is connected to the subtractor module and is used to perform proportional-integral adjustment on the position error signal to obtain a current command signal; the open-loop transfer function of the position loop proportional-integral adjustment module is expressed as:

[0009] G PI (s) = Kpp(1+Kpi / s)

[0010] Among them, Kpp is the proportional gain coefficient of the position loop, Kpi is the integral gain coefficient of the position loop, and s is a complex frequency domain variable;

[0011] A phase advance adjustment module is connected to the position loop proportional integral adjustment module and is used to perform phase advance adjustment on the current command signal; the open-loop transfer function of the phase advance adjustment module is expressed as:

[0012] G Lead (s)=(αs+ω pc ) / (s+ω pc )

[0013] Among them, α is the leading coefficient, the value of α is greater than 1, ω pc is the filtering frequency;

[0014] A low-pass filter is connected to the phase advance adjustment module and is used to filter the adjusted current command signal; the open-loop transfer function of the low-pass filter is expressed as:

[0015]

[0016] Among them, ω1 is the low-pass filter cutoff frequency, ξ is the filter damping coefficient;

[0017] The current loop amplification and regulation module is connected to the low-pass filter and is used to amplify the filtered current command signal to obtain a target drive signal.

[0018] In one embodiment, the position loop proportional integral regulation module includes an operational amplifier U1, an operational amplifier U2, an operational amplifier U3, a variable resistor Rp, a variable resistor Rp2, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5 and a capacitor C1; the first end of the variable resistor Rp1 is used to receive the position error signal, the second end of the variable resistor Rp1 is connected to the ground, and the sliding contact end of the variable resistor Rp1 is connected to the in-phase input end of the operational amplifier U1; the inverting input end and the output end of the operational amplifier U1 are connected in common, and are respectively connected to the first end of the variable resistor Rp2 and the first end of the resistor R1; the second end of the resistor R1, the first end of the resistor R2 and the in-phase input end of the operational amplifier U2 The first and second ends of the resistor R2 and the first and second ends of the resistor R5 are connected in common; the second end of the resistor R2 is connected to the ground; the second end of the variable resistor Rp2 is connected to the ground, and the sliding contact end of the variable resistor Rp2 is connected to the first end of the resistor R3; the second end of the resistor R3, the first end of the capacitor C1 and the inverting input end of the operational amplifier U3 are connected; the non-inverting input end of the operational amplifier U3 is connected to the ground, the output end of the operational amplifier U3 is connected to the second end of the capacitor C1, and is connected to the first end of the resistor R4; the second end of the resistor R4, the first end of the resistor R5 and the inverting input end of the operational amplifier U2 are connected in common; the second end of the resistor R5 and the output end of the operational amplifier U2 are connected in common, and are connected to the phase advance adjustment module.

[0019] In one embodiment, the phase advance adjustment module includes an operational amplifier U4, an operational amplifier U5, an operational amplifier U6, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R1 capacitor C2, a capacitor C3 and a capacitor C4; the first end of the resistor R8 and the first end of the capacitor C2 are connected in common to receive the current command signal together; the second end of the capacitor C2, the inverting input end of the operational amplifier U4, the first end of the capacitor C3, and the first end of the resistor R6 are connected in common; the non-inverting input end of the operational amplifier U4 is connected to the ground; the output end of the operational amplifier U4, the second end of the capacitor C3, and the second end of the resistor R6 Commonly connected, and connected to the first end of the resistor R7; the second end of the resistor R8, the first end of the resistor R9, the first end of the capacitor C4 and the non-inverting input terminal of the operational amplifier U5 are commonly connected; the inverting input terminal of the operational amplifier U5 is connected to the ground terminal; the output terminal of the operational amplifier U5 is connected to the first end of the resistor R10; the second end of the resistor R7, the second end of the resistor R10, the first end of the resistor R11 and the inverting input terminal of the operational amplifier U6 are connected; the non-inverting input terminal of the operational amplifier U6 is connected to the ground terminal; the second end of the resistor R11 is commonly connected to the output terminal of the operational amplifier U6, and is connected to the low-pass filter.

[0020] In one embodiment, α is equal to ω pc equal The resistance values ​​of the resistor R8 , the resistor R9 and the resistor R6 are the same, the resistance values ​​of the resistor R7 , the resistor R10 and the resistor R11 are the same, and the capacitance values ​​of the capacitor C3 and the capacitor C4 are the same.

[0021] In one embodiment, the low-pass filter includes a resistor R12, a resistor R13, a resistor R14, a resistor R15, a capacitor C4, a capacitor C5 and an operational amplifier U7; the first end of the resistor R12 is connected to the phase advance adjustment module, and the second end of the resistor R12 is respectively connected to the first end of the resistor R13 and the first end of the capacitor C4; the second end of the resistor R13 is respectively connected to the first end of the capacitor C5 and the in-phase input terminal of the operational amplifier U7; the inverting input terminal of the operational amplifier U7 is respectively connected to the first end of the resistor R14 and the first end of the resistor R15; the second end of the resistor R14 is connected to the ground terminal; the second end of the capacitor C4, the second end of the resistor R15 and the output terminal of the operational amplifier U7 are commonly connected, and are connected to the current loop amplification and adjustment module.

[0022] In one embodiment, ω1 is equal to ξ is equal to The resistance value of the resistor R15 is 0.

[0023] In one embodiment, the current loop amplification and adjustment module includes a resistor R16, a resistor R17, a variable resistor Rp3 and an operational amplifier U8; the first end of the resistor R16 is connected to the low-pass filter, and the second end of the resistor R16 is connected to the in-phase input end of the operational amplifier U8; the inverting input end of the operational amplifier U8 is respectively connected to the first end of the variable resistor Rp3 and the first end of the resistor R17; the second end and the sliding contact end of the variable resistor Rp3 are respectively connected to the ground end; the second end of the resistor R17 is connected to the output end of the operational amplifier U8.

[0024] In one embodiment, the voice coil motor driving circuit further includes:

[0025] The current sampling feedback module is connected to the second end of the resistor R16 and the in-phase input end of the operational amplifier U8 respectively, and is used to collect the current feedback signal of the voice coil motor and provide it to the current loop amplification and regulation module.

[0026] In one embodiment, the current sampling feedback module includes a resistor R18, a resistor R19, a resistor R20, a resistor R2 capacitor C6 and an operational amplifier U9; the first end of the resistor R18 and the first end of the resistor R19 are respectively used to receive the current feedback signal of the voice coil motor, and the second end of the resistor R18 is connected to the ground; the second end of the resistor R19 is respectively connected to the first end of the resistor R20 and the first end of the capacitor C6; the inverting input end of the operational amplifier U9 is connected to the ground; the second end of the resistor R20, the second end of the capacitor C6, the output end of the operational amplifier U9 and the first end of the resistor R21 are commonly connected; the second end of the resistor R21 is respectively connected to the second end of the resistor R16 and the in-phase input end of the operational amplifier U8.

[0027] In one embodiment, the subtractor module includes: an operational amplifier U10, a buffer U1, a buffer U12, a resistor R22, a resistor R23, a resistor R24 ​​and a resistor R25; the in-phase input terminal of the operational amplifier U10 is used to receive the position input signal, the inverting input terminal and the output terminal of the operational amplifier U10 are connected in common, and are connected to the first end of the resistor R22; the second end of the resistor R22 is respectively connected to the first end of the resistor R23 and the in-phase input terminal of the buffer U11; the second end of the resistor R23 is connected to the ground; the in-phase input terminal of the buffer U12 is used to receive the position feedback signal, the inverting input terminal and the output terminal of the buffer U12 are connected in common, and are connected to the first end of the resistor R24; the second end of the resistor R24 ​​is respectively connected to the first end of the resistor R25 and the inverting input terminal of the buffer U12; the second end of the resistor R25 is connected to the output terminal of the buffer U12, and is connected to the position loop proportional integral adjustment module.

[0028] The above-mentioned dual-loop structure of position loop + current loop is designed, and proportional-integral regulation is combined with phase lead regulation. Compared with the traditional three-loop structure, the following error of the ramp command is eliminated, and the trajectory tracking accuracy and dynamic response performance are optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is the structural block diagram of the traditional P-PI-PI three-loop controller;

[0030] Figure 2 This is a structural block diagram of a voice coil motor driving circuit according to an embodiment of the present application;

[0031] Figure 3 A schematic structural diagram of a voice coil motor driving circuit according to another embodiment of the present application;

[0032] Figure 4 This is a circuit structure diagram of a position loop proportional-integral regulation module according to an embodiment of the present application;

[0033] Figure 5 A circuit structure diagram of a phase advance adjustment module according to an embodiment of the present application;

[0034] Figure 6 A circuit diagram of a low-pass filter according to an embodiment of the present application;

[0035] Figure 7 A current loop amplification and regulation module according to an embodiment of the present application;

[0036] Figure 8 A schematic structural diagram of a voice coil motor driving circuit according to another embodiment of the present application;

[0037] Fig. 9This is a circuit structure diagram of a current sampling feedback module according to an embodiment of the present application;

[0038] Fig.10 FIG. 4 is a circuit structure diagram of a subtractor module according to an embodiment of the present application. DETAILED DESCRIPTION

[0039] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0040] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0041] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly. The connection can be a direct connection or an indirect connection.

[0042] In addition, in this application, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0043] The schematic diagram of the traditional P-PI-PI three-loop controller can be referred to Figure 1 As shown, G p (s) is the position loop transfer function, G S (s) is the transfer function of the speed loop controller, Gcc(s) is the transfer function of the current loop controller, P ref is the position loop input signal, ω ref is the output signal of the position loop. Since the current loop bandwidth is much higher than the speed loop bandwidth, the current closed-loop transfer function Gcc(s) is equivalent to 1. The transfer functions of the speed controller and the position controller can be expressed as:

[0044] G P (s) = K pp

[0045]

[0046] In this way, the open-loop transfer function of the position loop is expressed as:

[0047]

[0048] Among them, K pp is the position loop gain coefficient, K sp is the speed loop gain coefficient, K si is the speed loop integral coefficient, K f is the thrust coefficient of the motor, M is the mass of the motor, and s is a complex frequency domain variable.

[0049] From the above formula, we can see that the P-PI-PI three-ring structure is a type I system. According to the final value theorem of Laplace transform, the steady-state error of the system is:

[0050]

[0051] Where R(s) is the input signal, H(s) is the feedback coefficient, and when the ramp command is input, R(s) is equal to 1 / s 2 , H(s) is equal to 1, and after substituting into the above formula, we can get e ss (∞) is not equal to 0, so there is a steady-state error.

[0052] In this regard, the present invention provides a voice coil motor driving circuit without steady-state error, such as Figure 2 As shown, the voice coil motor driving circuit includes a subtractor module 110, a position loop proportional integral adjustment module 120, a phase advance adjustment module 130, a low-pass filter 140 and a current loop amplification adjustment module 150; wherein the subtractor module 110 is used to receive a position input signal and a position feedback signal, and perform subtraction processing on the position input signal and the position feedback signal to obtain a position error signal; the position loop proportional integral adjustment module 120 is connected to the subtractor module 110, and is used to perform proportional integral adjustment on the position error signal to obtain a current command signal; the open-loop transfer function of the position loop proportional integral adjustment module 120 is expressed as:

[0053] G PI (s) = Kpp(1+Kpi / s)

[0054] Wherein, Kpp is the position loop gain coefficient, Kpi is the position loop integral gain coefficient, and s is a complex frequency domain variable; the phase advance adjustment module 130 is connected to the position loop proportional integral adjustment module 120, and is used to perform phase advance adjustment on the current command signal; the open-loop transfer function of the phase advance adjustment module 130 is expressed as:

[0055] G Lead(s)=(αs+ω pc ) / (s+αω pc )

[0056] Among them, α is the leading coefficient, the value of α is greater than 1, ω pc is the filtering frequency; the low-pass filter 140 is connected to the phase advance adjustment module 130 for filtering the adjusted current command signal; the open-loop transfer function of the low-pass filter 140 is expressed as:

[0057]

[0058] Among them, ω1 is the low-pass filter cutoff frequency, ξ is the filter damping coefficient; the current loop amplification and adjustment module 150 is connected to the low-pass filter 140, and is used to amplify the filtered current command signal to obtain a target drive signal.

[0059] Figure 3 This is a schematic diagram of the signal control of the voice coil motor drive circuit. Figure 3 As shown, the position loop proportional integral adjustment module 120, the phase advance adjustment module 130 and the low-pass filter 140 together constitute the position controller G p (s), P ref is the position input signal, i q is the drive signal output by the position controller, P1 is the motor position signal, which is also fed back to the input of the subtractor module as a position feedback signal. Based on this, the transfer function of the position controller can be expressed as:

[0060]

[0061] According to the final value theorem of Laplace transform, the steady-state error of the system is:

[0062]

[0063] Where R(s) is the input signal, H(s) is the feedback coefficient, and when the ramp command is input, R(s) is equal to 1 / s 2 , H(s) is equal to 1, and after substituting into the above formula, we can get e ss (∞) is equal to 0, so there is no steady-state error.

[0064] In this way, the above-mentioned dual-loop structure of position loop + current loop is designed, and proportional-integral regulation is combined with phase lead regulation. Compared with the traditional three-loop structure, the following error of the ramp command is eliminated, and the trajectory tracking accuracy and dynamic response performance are optimized.

[0065] In one embodiment, Figure 4As shown, the position loop proportional-integral adjustment module 120 includes an operational amplifier U1, an operational amplifier U2, an operational amplifier U3, a variable resistor Rp1, a variable resistor Rp2, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5 and a capacitor C1; the first end of the variable resistor Rp1 is used to receive the position error signal, the second end of the variable resistor Rp1 is connected to the ground, and the sliding contact end of the variable resistor Rp1 is connected to the in-phase input end of the operational amplifier U1; the inverting input end and the output end of the operational amplifier U1 are connected in common, and are respectively connected to the first end of the variable resistor Rp2 and the first end of the resistor R1; the second end of the resistor R1, the first end of the resistor R2 and the operational amplifier U 2 is connected in common; the second end of the resistor R2 is connected to the ground; the second end of the variable resistor Rp2 is connected to the ground, and the sliding contact end of the variable resistor Rp2 is connected to the first end of the resistor R3; the second end of the resistor R3, the first end of the capacitor C1 and the inverting input end of the operational amplifier U3 are connected; the in-phase input end of the operational amplifier U3 is connected to the ground, the output end of the operational amplifier U3 is connected to the second end of the capacitor C1, and is connected to the first end of the resistor R4; the second end of the resistor R4, the first end of the resistor R5 and the inverting input end of the operational amplifier U2 are connected in common; the second end of the resistor R5 and the output end of the operational amplifier U2 are connected in common, and are connected to the phase advance adjustment module 130.

[0066] In one embodiment, Kpp is equal to KPI is equal to R4=R1,R2=R5,R 01 The variable resistor Rp1 is connected to the resistance of the path where the operational amplifier U1 is located. 02 The variable resistor Rp1 is connected to the ground terminal. 11 The variable resistor Rp2 is connected to the resistance of the path where the operational amplifier U2 is located. 12 It is the part of the resistance that the variable resistor Rp2 is connected to the ground.

[0067] Understandable, reference Figure 4 As shown, the position error signal is represented by Vin, the current command signal is represented by Vout, and the voltage at the in-phase input terminal of the operational amplifier U1 is V1, the voltage at the first terminal of the resistor R3 is V2, and the voltage at the output terminal of the operational amplifier U2 is V3. According to the circuit in the figure, we can get:

[0068]

[0069] Since R4=R1, R2=R5, we have:

[0070]

[0071] Combining the above formula, we can get:

[0072]

[0073] After sorting, we can get:

[0074]

[0075] Let Kpp be equal to KPI is equal to Then we have:

[0076]

[0077] Thus, the position loop proportional integral adjustment module 120 can be provided with a corresponding transfer function by using the above circuit structure; and, since the resistor R 01 , resistor R 02 , resistor R 11 , resistor R 12 It is obtained by adjusting the variable resistor, and its resistance value is adjustable, thereby realizing the adjustment of Kpp and Kpi. The circuit structure is simple and easy to operate.

[0078] In one embodiment, the phase advance adjustment module 130 includes an operational amplifier U4, an operational amplifier U5, an operational amplifier U6, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a capacitor C2, a capacitor C3 and a capacitor C4; the first end of the resistor R8 and the first end of the capacitor C2 are connected in common for receiving the current command signal together; the second end of the capacitor C2, the inverting input end of the operational amplifier U4, the first end of the capacitor C3, and the first end of the resistor R6 are connected in common; the non-inverting input end of the operational amplifier U4 is connected to the ground; the output end of the operational amplifier U4, the second end of the capacitor C3, the resistor The second end of R6 is connected in common and connected to the first end of resistor R7; the second end of resistor R8, the first end of resistor R9, the first end of capacitor C4 and the non-inverting input terminal of operational amplifier U5 are connected in common; the inverting input terminal of operational amplifier U5 is connected to the ground terminal; the output terminal of operational amplifier U5 is connected to the first end of resistor R10; the second end of resistor R7, the second end of resistor R10, the first end of resistor R11 and the inverting input terminal of operational amplifier U6 are connected; the non-inverting input terminal of operational amplifier U6 is connected to the ground terminal; the second end of resistor R11 is connected in common with the output terminal of operational amplifier U6, and connected to low-pass filter 140.

[0079] In one embodiment, α is equal to ω pc equal R8=R9=R6, C3=C4, R7=R10=R11.

[0080] Understandable, reference Figure 5As shown, the current command signal is represented by Vin, and the signal after phase advance adjustment is represented by Vout. Assuming that the voltage at the output of operational amplifier U4 is V4, and the voltage at the output of operational amplifier U5 is V5, according to the circuit in the figure, we can get:

[0081]

[0082] Since R8=R9=R6, C3=C4, R7=R10=R11, we have:

[0083]

[0084] Since α is equal to ω pc equal So we can get:

[0085]

[0086] Thus, the above circuit structure can be used to enable the phase advance adjustment module 130 to have a corresponding transfer function.

[0087] In one embodiment, Figure 6 As shown, the low-pass filter 140 includes a resistor R12, a resistor R13, a resistor R14, a resistor R15, a capacitor C4, a capacitor C5 and an operational amplifier U7; the first end of the resistor R12 is connected to the phase advance adjustment module 130, and the second end of the resistor R12 is respectively connected to the first end of the resistor R13 and the first end of the capacitor C4; the second end of the resistor R13 is respectively connected to the first end of the capacitor C5 and the in-phase input terminal of the operational amplifier U7; the inverting input terminal of the operational amplifier U7 is respectively connected to the first end of the resistor R14 and the first end of the resistor R15; the second end of the resistor R14 is connected to the ground; the second end of the capacitor C4, the second end of the resistor R15 and the output terminal of the operational amplifier U7 are commonly connected, and are connected to the current loop amplification and adjustment module 150.

[0088] Among them, ω1 is equal to ξ is equal to

[0089] Understandably, Then we have:

[0090]

[0091] Let R15=0, that is, Aup=1, then:

[0092]

[0093] Since ω1 is equal to ξ is equal to From this we can get:

[0094]

[0095] Thus, the above circuit structure can be used to enable the low-pass filter 140 to have a corresponding transfer function.

[0096] In one embodiment, Figure 7 As shown, the current loop amplification and regulation module 150 includes a resistor R16, a resistor R17, a variable resistor Rp3 and an operational amplifier U8; the first end of the resistor R16 is connected to the low-pass filter 140, and the second end of the resistor R16 is connected to the in-phase input terminal of the operational amplifier U8; the inverting input terminal of the operational amplifier U8 is respectively connected to the first end of the variable resistor Rp3 and the first end of the resistor R17; the second end and the sliding contact end of the variable resistor Rp3 are respectively connected to the ground terminal; the second end of the resistor R17 is connected to the output terminal of the operational amplifier U8.

[0097] It can be understood that the operational amplifier U8 can amplify and output the current command signal filtered by the low-pass filter 140. By adjusting the resistance value of the variable resistor Rp7, thereby changing the ratio of the resistor R17 to the variable resistor Rp7, the gain of the current command signal can be adjusted, and finally the target drive signal of the desired size is obtained.

[0098] In one embodiment, Figure 8 As shown, the voice coil motor driving circuit also includes a current sampling feedback module 160, which is respectively connected to the second end of the resistor R16 and the in-phase input end of the operational amplifier U8, for collecting the current feedback signal of the voice coil motor and providing it to the current loop amplification and adjustment module 150.

[0099] It can be understood that the current sampling feedback module 160 can directly feed back the collected current feedback signal to the non-phase input terminal of the operational amplifier U8, thereby realizing feedback adjustment of the current command signal input to the operational amplifier U8, and ultimately improving the accuracy of the motor drive.

[0100] In one embodiment, Fig. 9As shown, the current sampling feedback module 160 includes a resistor R18, a resistor R19, a resistor R20, a resistor R21, a capacitor C6 and an operational amplifier U9; the first end of the resistor R18 and the first end of the resistor R19 are respectively used to receive the current feedback signal of the voice coil motor, and the second end of the resistor R18 is connected to the ground; the second end of the resistor R19 is respectively connected to the first end of the resistor R20 and the first end of the capacitor C6; the inverting input terminal of the operational amplifier U9 is connected to the ground; the second end of the resistor R20, the second end of the capacitor C6, the output end of the operational amplifier U9 and the first end of the resistor R21 are commonly connected; the second end of the resistor R21 is respectively connected to the second end of the resistor R16 and the non-inverting input terminal of the operational amplifier U8.

[0101] It can be understood that the operational amplifier U9 can achieve gain adjustment of the current feedback signal by setting resistors and capacitors with appropriate values ​​in its feedback loop so that their values ​​match the current indication signal to achieve feedback adjustment of the current indication signal.

[0102] In one embodiment, Fig.10 As shown, the subtractor module 110 includes: an operational amplifier U10, a buffer U11, a buffer U12, a resistor R22, a resistor R23, a resistor R24 ​​and a resistor R25; the non-inverting input terminal of the operational amplifier U10 is used to receive a position input signal, the inverting input terminal and the output terminal of the operational amplifier U10 are connected in common, and are connected to the first end of the resistor R22; the second end of the resistor R22 is respectively connected to the first end of the resistor R23 and the non-inverting input terminal of the buffer U11; the second end of the resistor R23 is connected to the ground; the non-inverting input terminal of the buffer U12 is used to receive a position feedback signal, the inverting input terminal and the output terminal of the buffer U12 are connected in common, and are connected to the first end of the resistor R24; the second end of the resistor R24 ​​is respectively connected to the first end of the resistor R25 and the inverting input terminal of the buffer U12; the second end of the resistor R25 is connected to the output terminal of the buffer U12, and is connected to the position loop proportional integral adjustment module 120.

[0103] It can be understood that the position input signal and the position feedback signal are respectively passed through a first-level buffer, and then a subtraction operation is performed using the buffer U12 to obtain a position error signal; since a buffer is provided at the input, the final output position error signal can be guaranteed to be stable and accurate.

[0104] An embodiment of the present invention further provides a voice coil motor driving circuit, including a subtractor module 110, a position loop proportional integral adjustment module 120, a phase advance adjustment module 130, a low-pass filter 140, a current loop amplification adjustment module 150 and a current sampling feedback module 160. The specific circuit structure of each module can refer to the voice coil motor driving circuit of the above embodiment, which will not be repeated here.

[0105] The above description is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A voice coil motor driving circuit, characterized in that: include: A subtractor module, used for receiving a position input signal and a position feedback signal, and performing subtraction processing on the position input signal and the position feedback signal to obtain a position error signal; The position loop proportional-integral adjustment module is connected to the subtractor module and is used to perform proportional-integral adjustment on the position error signal to obtain a current command signal; the open-loop transfer function of the position loop proportional-integral adjustment module is expressed as: G PI (s)=Kpp(1+Kpi / s) Among them, Kpp is the proportional gain coefficient of the position loop, Kpi is the integral gain coefficient of the position loop, and s is a complex frequency domain variable; A phase advance adjustment module is connected to the position loop proportional integral adjustment module and is used to perform phase advance adjustment on the current command signal; the open-loop transfer function of the phase advance adjustment module is expressed as: G Lead (s)=(αs+ω) pc ) / (s+ω pc ) Among them, α is the leading coefficient, the value of α is greater than 1, ω pc is the filtering frequency; A low-pass filter is connected to the phase advance adjustment module and is used to filter the adjusted current command signal; the open-loop transfer function of the low-pass filter is expressed as: Among them, ω1 is the low-pass filter cutoff frequency, ξ is the filter damping coefficient; The current loop amplification and regulation module is connected to the low-pass filter and is used to amplify the filtered current command signal to obtain a target drive signal.

2. The voice coil motor driving circuit according to claim 1, characterized in that: The position loop proportional-integral adjustment module includes an operational amplifier U1, an operational amplifier U2, an operational amplifier U3, a variable resistor Rp1, a variable resistor Rp2, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5 and a capacitor C1; the first end of the variable resistor Rp1 is used to receive the position error signal, the second end of the variable resistor Rp1 is connected to the ground, and the sliding contact end of the variable resistor Rp1 is connected to the in-phase input end of the operational amplifier U1; the inverting input end and the output end of the operational amplifier U1 are connected in common, and are respectively connected to the first end of the variable resistor Rp2 and the first end of the resistor R1; the second end of the resistor R1, the first end of the resistor R2 and the in-phase input end of the operational amplifier U2 are connected in common ; The second end of the resistor R2 is connected to the ground; the second end of the variable resistor Rp2 is connected to the ground, and the sliding contact end of the variable resistor Rp2 is connected to the first end of the resistor R3; the second end of the resistor R3, the first end of the capacitor C1 and the inverting input end of the operational amplifier U3 are connected; the non-inverting input end of the operational amplifier U3 is connected to the ground, the output end of the operational amplifier U3 is connected to the second end of the capacitor C1, and is connected to the first end of the resistor R4; the second end of the resistor R4, the first end of the resistor R5 and the inverting input end of the operational amplifier U2 are connected in common; the second end of the resistor R5 and the output end of the operational amplifier U2 are connected in common, and are connected to the phase advance adjustment module.

3. The voice coil motor driving circuit according to claim 1, characterized in that: The phase advance adjustment module includes an operational amplifier U4, an operational amplifier U5, an operational amplifier U6, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a capacitor C2, a capacitor C3 and a capacitor C4; the first end of the resistor R8 and the first end of the capacitor C2 are connected together to receive the current command signal together; the second end of the capacitor C2, the inverting input end of the operational amplifier U4, the first end of the capacitor C3, and the first end of the resistor R6 are connected together; the non-inverting input end of the operational amplifier U4 is connected to the ground; the output end of the operational amplifier U4, the second end of the capacitor C3, and the second end of the resistor R6 are connected together, And connected to the first end of the resistor R7; the second end of the resistor R8, the first end of the resistor R9, the first end of the capacitor C4 and the non-inverting input terminal of the operational amplifier U5 are commonly connected; the inverting input terminal of the operational amplifier U5 is connected to the ground terminal; the output terminal of the operational amplifier U5 is connected to the first end of the resistor R10; the second end of the resistor R7, the second end of the resistor R10, the first end of the resistor R11 and the inverting input terminal of the operational amplifier U6 are connected; the non-inverting input terminal of the operational amplifier U6 is connected to the ground terminal; the second end of the resistor R11 is commonly connected to the output terminal of the operational amplifier U6, and is connected to the low-pass filter.

4. The voice coil motor driving circuit according to claim 3, characterized in that: α is equal to ω pc equal The resistance values ​​of the resistor R8 , the resistor R9 and the resistor R6 are the same, the resistance values ​​of the resistor R7 , the resistor R10 and the resistor R11 are the same, and the capacitance values ​​of the capacitor C3 and the capacitor C4 are the same.

5. The voice coil motor driving circuit according to claim 1, characterized in that: The low-pass filter includes a resistor R12, a resistor R13, a resistor R14, a resistor R15, a capacitor C4, a capacitor C5 and an operational amplifier U7; the first end of the resistor R12 is connected to the phase advance adjustment module, and the second end of the resistor R12 is connected to the first end of the resistor R13 and the first end of the capacitor C4 respectively. The first terminal of the resistor R13 is connected to the first terminal of the capacitor C5 and the in-phase input terminal of the operational amplifier U7 respectively; the inverting input terminal of the operational amplifier U7 is connected to the first terminal of the resistor R14 and the first terminal of the resistor R15 respectively; the second terminal of the resistor R14 is connected to the ground terminal; the second terminal of the capacitor C4, the second terminal of the resistor R15 and the output terminal of the operational amplifier U7 are connected in common, and are connected to the current loop amplification and adjustment module.

6. The voice coil motor driving circuit according to claim 5, characterized in that: ω1 is equal to ξ is equal to The resistance value of the resistor R15 is 0.

7. The voice coil motor driving circuit according to claim 1, characterized in that: The current loop amplification and adjustment module includes a resistor R16, a resistor R17, a variable resistor Rp3 and an operational amplifier U8; the first end of the resistor R16 is connected to the low-pass filter, and the second end of the resistor R16 is connected to the in-phase input end of the operational amplifier U8; the inverting input end of the operational amplifier U8 is respectively connected to the first end of the variable resistor Rp3 and the first end of the resistor R17; the second end and the sliding contact end of the variable resistor Rp3 are respectively connected to the ground end; the second end of the resistor R17 is connected to the output end of the operational amplifier U8.

8. The voice coil motor driving circuit according to claim 7, characterized in that: The voice coil motor driving circuit also includes: The current sampling feedback module is connected to the second end of the resistor R16 and the in-phase input end of the operational amplifier U8 respectively, and is used to collect the current feedback signal of the voice coil motor and provide it to the current loop amplification and regulation module.

9. The voice coil motor driving circuit according to claim 8, characterized in that: The current sampling feedback module includes a resistor R18, a resistor R19, a resistor R20, a resistor R21, a capacitor C6 and an operational amplifier U9; the first end of the resistor R18 and the first end of the resistor R19 are respectively used to receive the current feedback signal of the voice coil motor, and the second end of the resistor R18 is connected to the ground; the second end of the resistor R19 is respectively connected to the first end of the resistor R20 and the first end of the capacitor C6; the inverting input end of the operational amplifier U9 is connected to the ground; the second end of the resistor R20, the second end of the capacitor C6, the output end of the operational amplifier U9 and the first end of the resistor R21 are commonly connected; the second end of the resistor R21 is respectively connected to the second end of the resistor R16 and the in-phase input end of the operational amplifier U8.

10. The voice coil motor driving circuit according to claim 1, characterized in that: The subtractor module includes: an operational amplifier U10, a buffer U11, a buffer U12, a resistor R22, a resistor R23, a resistor R24 ​​and a resistor R25; the non-inverting input terminal of the operational amplifier U10 is used to receive the position input signal, the inverting input terminal and the output terminal of the operational amplifier U10 are connected in common, and are connected to the first end of the resistor R22; the second end of the resistor R22 is respectively connected to the first end of the resistor R23 and the non-inverting input terminal of the buffer U11; the second end of the resistor R23 is connected to the ground; the non-inverting input terminal of the buffer U12 is used to receive the position feedback signal, the inverting input terminal and the output terminal of the buffer U12 are connected in common, and are connected to the first end of the resistor R24; the second end of the resistor R24 ​​is respectively connected to the first end of the resistor R25 and the inverting input terminal of the buffer U12; the second end of the resistor R25 is connected to the output terminal of the buffer U12, and is connected to the position loop proportional integral adjustment module.

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