A compensation circuit and control method for phase delay acquisition of switch Hall sensor

Abstract

The present invention discloses a compensation circuit for phase delay acquisition of a switch Hall sensor, comprising: a voltage divider module, an RC filter module, and an adjustment module; the voltage divider module is connected to the RC filter module, and is used to acquire the output electrical signal of the Hall sensor and divide the electrical signal; the RC filter module is connected to the adjustment module, and is used to filter and phase-adjust the electrical signal processed by the voltage divider module, and eliminate the interference of high-frequency harmonics; the adjustment module is used to adjust the phase lag generated by the RC filter module on the electrical signal. The present invention only utilizes a PWM function required by the original single-chip microcomputer, and only adds an adjustment module without changing the original hardware circuit, so as to adjust the phase lag during medium and high-speed operation; compared with the traditional adjustment method, it not only has stronger operability, but also has low cost.

Description

Technical Field

[0001] The invention relates to the technical field of brushless direct current motors, and in particular to a compensation circuit and a control method for phase delay acquisition of a switch Hall sensor. Background Art

[0002] The brushless DC motor with switch Hall sensor has the advantages of high efficiency, low price, strong anti-interference ability, etc. Therefore, the brushless DC motor with switch Hall sensor has been widely used in more and more industries.

[0003] In the RC filter module of the traditional brushless DC motor with switch Hall sensor, the high-order harmonics generated by PWM are eliminated by parallel capacitor elements. In the RC filter module, a filter capacitor is generally connected in parallel at both ends of the filter resistor. When the high-order harmonics pass through, they are absorbed and stored by the capacitor to ensure that the motor is not disturbed by high-frequency signals when it is running; at the same time, the filter capacitor has the function of generating a phase shift angle in the back electromotive force zero-crossing detection method to ensure that the motor switches phases at the correct switching point, and then correctly adjusts the speed of the brushless DC motor with switch Hall sensor. However, as the Hall frequency continues to increase, this circuit structure will produce a phase lag. When it increases to a certain extent, the lag angle will cause the brushless DC motor to fail to switch phases at the correct switching point, resulting in inaccurate speed regulation and even motor jitter. Therefore, the phase lag generated by the traditional RC filter module will reduce the control ability of the motor and increase unnecessary losses. Summary of the invention

[0004] The present invention provides a compensation circuit and control method for phase delay of a switch Hall sensor acquisition, so as to solve the problem that the phase lag of the Hall signal caused by a traditional RC filter circuit leads to inaccurate motor control speed and unstable operation state.

[0005] The present invention provides a compensation circuit for phase delay of a switch Hall sensor, comprising: a voltage divider module, an RC filter module, and an adjustment module; the voltage divider module is connected to the RC filter module and is used to collect an output electrical signal of a Hall sensor and divide the electrical signal; the RC filter module is connected to the adjustment module and is used to filter and phase-adjust the electrical signal processed by the voltage divider module to eliminate interference from high-frequency harmonics; the adjustment module is used to adjust the phase lag generated by the RC filter module on the electrical signal.

[0006] Furthermore, the voltage divider module includes: a first resistor; the RC filtering module includes: a second resistor and a first capacitor; one end of the first resistor is connected to the pull-up voltage, and the other end is respectively connected to the output end of the Hall element and one end of the second resistor; the other end of the second resistor is respectively connected to one end of the first capacitor and the input and output ends of the MCU; the other end of the first capacitor is grounded; and the adjustment module is connected in parallel to both ends of the second resistor.

[0007] Furthermore, the regulating module includes: a third resistor and a first transistor; one end of the third resistor is respectively connected to one end of the first resistor, the output end of the Hall element, and one end of the second resistor, and the other end of the third resistor is connected to the collector of the first transistor; the base of the first transistor is connected to the PWM signal input end, and the emitter of the first transistor is respectively connected to the other end of the second resistor, one end of the first capacitor, and the input end of the MCU.

[0008] Furthermore, the regulation module includes: a fourth resistor and a first optocoupler; one end of the fourth resistor is respectively connected to one end of the first resistor, the output end of the Hall element, and one end of the second resistor, and the other end of the fourth resistor is connected to the collector of the transistor in the first optocoupler; the emitter of the transistor in the first optocoupler is connected to one end of the second resistor, one end of the first capacitor, and the input end of the MCU; the cathode of the light-emitting diode in the first optocoupler is grounded, and the anode of the light-emitting diode in the first optocoupler is connected to the PWM signal input end.

[0009] The present invention also provides a control method for a compensation circuit for a phase delay acquisition of a switch Hall sensor, comprising the following steps:

[0010] Step 1: Obtain the Hall frequency F through the high and low levels output by the Hall sensor;

[0011] Step 2: Determine whether the Hall frequency is greater than the first Hall frequency threshold f1. If it is greater than the first Hall frequency threshold, proceed to step 3. If it is less than the first Hall frequency threshold, return to step 1.

[0012] Step 3: Determine whether the Hall frequency is less than the second Hall frequency threshold f2; if it is less than the second Hall frequency threshold, proceed to step 4; if it is greater than the second Hall frequency threshold, proceed to step 5;

[0013] Step 4: Connect the adjustment module, make the adjustment module work in a semi-working state, calculate the duty cycle of the PWM of the adjustment module according to the current Hall frequency, adjust the phase lag, and compensate for the phase lag;

[0014] Step 5: Connect the regulation module, operate the regulation module in full working state, set the PWM duty cycle of the regulation module to 1 to adjust the phase lag, and compensate for the phase lag.

[0015] Furthermore, the specific calculation method of the first threshold value of the Hall frequency in step 2 is:

[0016]

[0017] Wherein, f1 is the first threshold value of the Hall frequency, and c0 is the capacitance value of the first capacitor C1 in the RC filter module.

[0018] Furthermore, the specific calculation method of the second threshold value of the Hall frequency in step 3 is:

[0019]

[0020] Among them, f2 is the second threshold of the Hall frequency, r0 is the resistance value of the second resistor R2 in the RC filter module, the third resistor R3 and the fourth resistor R4 in the adjustment module, and c0 is the capacitance value of the first capacitor C1 in the RC filter module.

[0021] Furthermore, in step 4, the duty cycle of the PWM of the regulating module needs to be calculated according to the current Hall frequency. The specific formula is as follows:

[0022]

[0023] Wherein, c0 is the capacitance value of the first capacitor C1 in the RC filter module, f is the Hall frequency, and r0 is the resistance value of the second resistor R2 in the RC filter module, the third resistor R3 in the adjustment module, and the fourth resistor R4.

[0024] Beneficial effects of the present invention:

[0025] 1. The present invention utilizes only a PWM function that is essential for the original single-chip microcomputer. On the basis of not changing the original hardware circuit, only one adjustment module is added to adjust the phase lag during medium and high-speed operation. Compared with the traditional adjustment method, it not only has stronger operability but also low cost.

[0026] 2. In the control method of the present invention, the current Hall frequency is firstly obtained, and then the Hall frequency is interval detected. By adjusting the PWM duty cycle, different lag compensations are performed on the RC filter modules in different frequency bands. This not only does not increase the operation steps and time of the motor, but also realizes closed-loop regulation, real-time regulation and adaptive regulation in the operation of medium and high-speed motors.

[0027] 3. The present invention reduces the phase lag generated by the brushless DC motor with a switch Hall sensor during medium and high-speed operation by adjusting the RC filter module, reduces the impact of this lag on high-performance control, avoids motor jitter during acceleration, and improves control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the present invention in any way. In the accompanying drawings:

[0029] Figure 1 A circuit diagram for a specific implementation of the present invention;

[0030] Figure 2 Another circuit diagram for a specific implementation of the present invention;

[0031] Figure 3 The present invention is a flowchart of a control method specifically implemented in the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0033] An embodiment of the present invention provides an excitation control device for a synchronous motor, such as Figure 1 As shown, it includes: a voltage divider module, an RC filter module, and an adjustment module; the voltage divider module is connected to the RC filter module, and is used to collect the output electrical signal of the Hall sensor and divide the electrical signal; the RC filter module is connected to the adjustment module, and is used to filter and phase-adjust the electrical signal processed by the voltage divider module, eliminate the interference of high-frequency harmonics to ensure the control ability of the motor, ensure that the motor switches phases at the correct switching point after phase adjustment, and transmit the filtered and phase-adjusted electrical signal as output to the single-chip microcomputer; the adjustment module is used to solve the phase lag problem caused by the RC filter module on the electrical signal.

[0034] The voltage divider module includes a first resistor R1; wherein one end of the first resistor R1 is connected to the pull-up voltage 5V, and the other end of the first resistor R1 is connected to the output end of the Hall element and serves as the output end of the voltage divider module.

[0035] The RC filter module includes a second resistor R2 and a first capacitor C1; one end of the second resistor R2 is connected to the output end of the voltage divider module, and the other end of the second resistor R2 is connected to one end of the first capacitor C1 and serves as the output end of the RC filter module; the other end of the first capacitor C1 is connected to the ground.

[0036] The regulating module includes a third resistor R3 and an NPN transistor VT1. One end of the third resistor R3 is connected to the output end of the voltage divider module, and the other end of the third resistor R3 is connected to the collector c of the NPN transistor VT1. The base b and emitter e of the NPN transistor VT1 are respectively connected to the output end of the RC filter module and the PWM signal end.

[0037] like Figure 2 As shown, the regulating module may further include a fourth resistor R4 and a first optical coupler T1, wherein the first optical coupler T1 includes a first diode D1 and a second transistor VT2 for converting an optical signal emitted by the first diode D1 into an electrical signal, one end of the fourth resistor R4 is connected to the output end of the voltage divider module, i.e., one end of the second resistor R2, the other end of the fourth resistor R4 is connected to the collector c of the second transistor VT2, the emitter e of the second transistor VT2 is connected to the other end of the second resistor R2, the cathode of the first diode D1 is connected to the ground, and the anode of the first diode D1 is connected to the PWM signal end.

[0038] like Figure 3 As shown, a control method for collecting phase delay of a switch Hall sensor includes the following steps:

[0039] Step S1: Obtain the Hall frequency F through the high and low levels output by the Hall sensor;

[0040] Step S2: Determine whether the Hall frequency is greater than the first Hall frequency threshold f1; if the condition is met, proceed to step S3; if the condition is not met, return to step S1;

[0041] Step S3: Determine whether the Hall frequency is less than the second Hall frequency threshold value f2; if the condition is met, proceed to step S4; if the condition is not met, proceed to step S5;

[0042] Step S4: access the adjustment module to calculate the duty cycle of PWM; adjust the duty cycle of PWM in real time according to the current Hall frequency to achieve the purpose of adjusting the phase lag;

[0043] Step S5: The regulation module is fully connected, and the duty cycle of PWM is 1.

[0044] Optionally, in step S2, the first threshold of the Hall frequency is calculated based on the situation that the phase lag does not exceed 1° and the regulating module does not work, and the specific calculation method is:

[0045]

[0046] Wherein, f1 is the first threshold value of the Hall frequency, and c0 is the capacitance value of the first capacitor C1 in the RC filter module.

[0047] For example, the capacitance of the first capacitor C1 in the RC filter module is c0=1000nf. When the phase lag exceeds 1° and the adjustment module is not working, the first threshold value of the Hall frequency is specifically:

[0048]

[0049] Optionally, in step S3, the second threshold of the Hall frequency is calculated based on the situation that the phase lag exceeds 1° and the regulating module is fully operational, and the specific calculation method is:

[0050]

[0051] Among them, f2 is the second threshold of the Hall frequency, r0 is the resistance value of the second resistor R2 in the RC filter module, the third resistor R3 and the fourth resistor R4 in the adjustment module, and c0 is the capacitance value of the first capacitor C1 in the RC filter module.

[0052] For example, the resistance value of the second resistor R2 in the RC filter module, the third resistor R3 and the fourth resistor R4 in the adjustment module is r0=200Ω, and the capacitance value of the first capacitor C1 in the RC filter module is c0=1000nf. When the phase lag exceeds 1° and the adjustment module does not work, the second threshold value of the Hall frequency is specifically:

[0053]

[0054] Optionally, the duty cycle pwm of the PWM signal to be adjusted in step S4 is calculated based on the phase lag exceeding 1° and the adjustment module working, and the specific calculation method is as follows:

[0055]

[0056] Wherein, c0 is the capacitance value of the first capacitor C1 in the RC filter module, f is the Hall frequency, and r0 is the resistance value of the second resistor R2 in the RC filter module, the third resistor R3 in the adjustment module, and the fourth resistor R4.

[0057] For example, the Hall frequency of a vacuum cleaner when running at high speed is 125000 Hz, the resistance value of the second resistor R2 in the RC filter module, the third resistor R3 and the fourth resistor R4 in the adjustment module is r0=200Ω, the capacitance value of the first capacitor C1 in the RC filter module is c0=1000nf, and the duty cycle pwm of the PWM wave is calculated based on the phase lag not exceeding 1° and the adjustment module not working:

[0058]

[0059] In the embodiment of the present invention, the resistance values ​​of the first resistor R1 in the voltage divider module, the second resistor R2 in the RC filter module, the third resistor R3 and the fourth resistor R4 in the adjustment module are all 200Ω, and the first capacitor C1 in the RC filter module is 1000nf.

[0060] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A control method for a compensation circuit for phase delay acquisition of a switch Hall sensor, wherein: The compensation circuit for the phase delay of the switch Hall sensor includes: a voltage divider module, an RC filter module, and an adjustment module; the voltage divider module is connected to the RC filter module, and is used to collect the output electrical signal of the Hall sensor and divide the electrical signal; the RC filter module is connected to the adjustment module, and is used to filter and phase-adjust the electrical signal processed by the voltage divider module to eliminate the interference of high-frequency harmonics; the adjustment module is used to adjust the phase lag generated by the RC filter module on the electrical signal. Characterized in that the method comprises the following steps: Step 1: Obtain the Hall frequency F through the high and low levels output by the Hall sensor; Step 2: Determine whether the Hall frequency is greater than the first Hall frequency threshold f1. If it is greater than the first Hall frequency threshold, proceed to step 3. If it is less than the first Hall frequency threshold, return to step 1. Step 3: Determine whether the Hall frequency is less than the second Hall frequency threshold f2; if it is less than the second Hall frequency threshold, proceed to step 4; if it is greater than the second Hall frequency threshold, proceed to step 5; Step 4: Connect the adjustment module, make the adjustment module work in a semi-working state, calculate the duty cycle of the PWM of the adjustment module according to the current Hall frequency, adjust the phase lag, and compensate for the phase lag; Step 5: Connect the regulation module, operate the regulation module in full working state, set the PWM duty cycle of the regulation module to 1 to adjust the phase lag, and compensate for the phase lag.

2. The control method of the compensation circuit for the phase delay of the switch Hall sensor acquisition as claimed in claim 1, characterized in that: The voltage divider module includes: a first resistor; the RC filtering module includes: a second resistor and a first capacitor; one end of the first resistor is connected to the pull-up voltage, and the other end is respectively connected to the output end of the Hall element and one end of the second resistor; the other end of the second resistor is respectively connected to one end of the first capacitor and the input and output ends of the MCU; the other end of the first capacitor is grounded; the adjustment module is connected in parallel to both ends of the second resistor.

3. The control method of the compensation circuit for the phase delay of the switch Hall sensor acquisition as claimed in claim 2, characterized in that: The regulating module includes: a third resistor and a first transistor; one end of the third resistor is respectively connected to one end of the first resistor, the output end of the Hall element, and one end of the second resistor, and the other end of the third resistor is connected to the collector of the first transistor; the base of the first transistor is connected to the PWM signal input end, and the emitter of the first transistor is respectively connected to the other end of the second resistor, one end of the first capacitor, and the input end of the MCU. Or, the adjustment module includes: a fourth resistor and a first optocoupler; one end of the fourth resistor is respectively connected to one end of the first resistor, the output end of the Hall element, and one end of the second resistor, and the other end of the fourth resistor is connected to the collector of the transistor in the first optocoupler; the emitter of the transistor in the first optocoupler is connected to one end of the second resistor, one end of the first capacitor, and the input end of the MCU; the cathode of the light-emitting diode in the first optocoupler is grounded, and the anode of the light-emitting diode in the first optocoupler is connected to the PWM signal input end.

4. The control method of the compensation circuit for the phase delay of the switch Hall sensor acquisition as claimed in claim 2, characterized in that: The specific calculation method of the first threshold value of the Hall frequency in step 2 is: Wherein, f1 is the first threshold value of the Hall frequency, and c0 is the capacitance value of the first capacitor C1 in the RC filter module.

5. The control method of the compensation circuit for the phase delay of the switch Hall sensor acquisition as claimed in claim 3, characterized in that: The specific calculation method of the second threshold value of the Hall frequency in step 3 is: Among them, f2 is the second threshold of the Hall frequency, r0 is the resistance value of the second resistor R2 in the RC filter module, the third resistor R3 and the fourth resistor R4 in the adjustment module, and c0 is the capacitance value of the first capacitor C1 in the RC filter module.

6. The control method of the compensation circuit for the phase delay of the switch Hall sensor acquisition as claimed in claim 3, characterized in that: In step 4, the duty cycle of the PWM of the regulating module needs to be calculated according to the current Hall frequency. The specific formula is as follows: Wherein, c0 is the capacitance value of the first capacitor C1 in the RC filter module, f is the Hall frequency, and r0 is the resistance value of the second resistor R2 in the RC filter module, the third resistor R3 in the adjustment module, and the fourth resistor R4.

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