An electrolytic capacitor-free driving method based on a position sensor-free control

Abstract

The application discloses a kind of electrolytic capacitorless driving methods based on position sensorless control, including the mathematical model of permanent magnet synchronous motor is designed sliding mode observer, the component of stator voltage in alpha-beta axis system is input for sliding mode observer, and output is stator current observation value;Sliding mode control function is obtained based on sliding mode control function sliding mode control function in alpha-beta axis system component;After eliminating q-axis current coupling, alpha-beta axis sliding mode observation value is further obtained;Based on extended state observer-locked loop extraction rotor position and speed information;Based on observed rotor position and speed, permanent magnet synchronous motor is closed-loop controlled.The application is mainly improved to sliding mode control function, constructs extended state observer-locked loop, eliminates the adverse effects of electrolytic capacitorless driving system q-axis current fluctuation on position observation.

Description

Technical Field

[0001] This invention relates to the field of motor control, and in particular to a sensorless, capacitor-free driving method based on position sensor-free control. Background Technology

[0002] Permanent magnet synchronous motors, with their advantages of high efficiency, high torque density, and high power density, are widely used in industrial drives, electric vehicles, and home appliances. In traditional motor drive systems, electrolytic capacitors suffer from drawbacks such as short lifespan, significant environmental pollution, and high cost. In recent years, the use of film capacitors as a replacement has become the mainstream solution in engineering applications, known as "electrolytic capacitor-free drive systems." The capacitance of film capacitors is typically only 1 / 50 to 1 / 20 that of electrolytic capacitors, resulting in reduced energy storage capacity. This leads to significant fluctuations in the DC bus voltage at twice the frequency of the power grid, thus affecting motor performance.

[0003] In the vector control system of permanent magnet synchronous motors, obtaining high-precision rotor position information in real time is crucial for achieving high-performance control. Therefore, rotor position sensors such as rotary transformers and encoders are typically installed on the motor. However, the installation of mechanical position sensors increases the difficulty and cost of motor manufacturing, and the sensor signals are susceptible to interference from external factors, reducing system reliability. In recent years, numerous scholars and engineers both domestically and internationally have conducted a series of studies on sensorless control of permanent magnet synchronous motors, effectively overcoming the inherent defects of mechanical sensors and gradually applying them to various motor products.

[0004] Sensorless control technology based on sliding mode observers exhibits low sensitivity to parameters and disturbances and strong robustness, thus finding widespread application in motor drive systems. However, for electrolytic capacitor-free drive systems, fluctuations in the DC bus voltage introduce additional harmonic interference, introducing AC components into the q-axis current, reducing the signal-to-noise ratio of the back EMF signal, and lowering the accuracy of rotor position estimation. Furthermore, the discontinuity of the sliding mode control function leads to significant system chattering, resulting in the inclusion of numerous high-frequency switching signals in the extended back EMF information. Therefore, it is essential to develop a sensorless control method applicable to electrolytic capacitor-free drive systems. Summary of the Invention

[0005] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the purpose of this invention is to provide an electrolytic capacitor-free driving method based on sensorless control.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A sensorless, capacitor-free driving method based on position sensor-free control includes:

[0008] Step 1: Convert the three-phase current ia i b i c The current i in the two-phase stationary coordinate system is obtained by Clark transformation. α i β ;

[0009] Step 2: Perform an inverse Park transformation on the output of the current controller to calculate the voltage u in the two-phase stationary coordinate system. α u β ;

[0010] Step 3: Based on the voltage u in the two-phase stationary coordinate system α u β Sliding mode control function component z α z β and the observed values ​​of the electric angular velocity of the motor rotor Calculate the current observations in the two-phase stationary coordinate system using a sliding mode observer.

[0011] Step 4: Observe the two-phase quiescent current values With actual value i α i β The difference is input into the sliding mode control function to obtain the sliding mode control function components z in the two-phase stationary coordinate system. α z β ;

[0012] Step 5: Convert the sliding mode control function components z in the two-phase stationary coordinate system obtained in Step 4. α z β After eliminating q-axis current coupling, we obtain

[0013] Step 6: Obtain the information from Step 5 The observed rotor angular velocity and rotor position are reconstructed after the extended state observer-phase-locked loop. And As input for steps 3 and 4, As input for steps 4 and 5.

[0014] Furthermore, an inverse Park transformation is performed on the output of the current controller to calculate the voltage u in the two-phase stationary coordinate system. α u β The motor voltage equation is as follows:

[0015]

[0016] Where i α i β It is the stator current component in a two-phase stationary coordinate system, R is the stator resistance, and ω is the stator current component.e It is the electric angular velocity of the motor rotor. It is the rotor permanent magnet flux linkage, L d L q These are the d-axis and q-axis inductance components in the dq-axis coordinate system, i d i q θ represents the d-axis and q-axis current components in the dq-axis coordinate system. e It is the rotor position angle.

[0017] Furthermore, in step 3, based on the voltage u in the two-phase stationary coordinate system... α u β Sliding mode control function component z α z β and the observed values ​​of the electric angular velocity of the motor rotor Calculate the current observations in the two-phase stationary coordinate system using a sliding mode observer. The implementation method is as follows:

[0018]

[0019] in, The observed value of the electric angular velocity of the motor rotor, z α z β These are the components of the sliding mode control function on the α-β axes.

[0020] Furthermore, in step 4, the two-phase stationary coordinate system current i α i β With current observations The difference is processed by the sliding mode control function to obtain the sliding mode control function component z in the two-phase stationary coordinate system. α z β .

[0021]

[0022] in, Here, k represents the rotor position observation value, and k is the sliding mode gain coefficient. c This is the sliding mode gain correction factor. To use rotor position angle observations The obtained motor dq-axis current, sgn is a sign function.

[0023] Furthermore, a sliding mode observer is constructed using the aforementioned sliding mode control function:

[0024]

[0025] in, This is the error between the observed current value and the actual detected current;

[0026] When the observed current error is zero, the extended back electromotive force in the two-phase stationary coordinate system can be reconstructed through the sliding mode control function:

[0027]

[0028] Furthermore, in step 5, the sliding mode control function components z in the two-phase stationary coordinate system from step 4 are... α z β After eliminating q-axis current coupling, we obtain

[0029]

[0030] Furthermore, the transfer function of the extended state observer-phase-locked loop is:

[0031]

[0032] A storage medium having a computer program stored thereon, which, when executed by a processor, implements the electrolytic capacitor-free driving method.

[0033] An apparatus includes a memory, a processor, and the electrolytic capacitor-free driving method stored in the memory and operable on the processor.

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] This invention solves the negative impact of electrolytic capacitor-free drive systems on position observation accuracy, and effectively improves the position observation accuracy of motor rotors controlled without position sensors based on electrolytic capacitor-free drive systems.

[0036] This invention improves the sliding mode control function by superimposing extended back EMF estimates, thereby reducing system chattering caused by the discontinuity of the sliding mode control function.

[0037] This invention constructs an extended state observer-phase-locked loop, which improves dynamic performance under both speed commands and load changes by introducing angular acceleration as an extended state variable.

[0038] The present invention provides a sensorless control method based on an electrolytic capacitor-free drive system, which is robust to uncertainties such as system disturbances and parameter perturbations, and thus can better realize sensorless control of permanent magnet synchronous motors. Attached Figure Description

[0039] Figure 1 This is a control block diagram of the present invention;

[0040] Figure 2 This is a block diagram for calculating the sliding mode gain correction coefficient of the present invention;

[0041] Figure 3 This is a block diagram illustrating the principle of the extended state observer-phase-locked loop of the present invention.

[0042] Figure 4(a) is a comparison between the traditional sliding mode control function after q-axis current decoupling and the reference back electromotive force;

[0043] Figure 4(b) is a comparison between the improved sliding mode control function after q-axis current decoupling and the reference back electromotive force.

[0044] Figure 5(a) shows the position error of the traditional sliding mode observer after q-axis current decoupling;

[0045] Figure 5(b) shows the position error of the improved sliding mode observer after q-axis current decoupling. Detailed Implementation

[0046] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0047] Example

[0048] like Figures 1-3 As shown, a sensorless control-based electrolytic capacitor-free driving method includes the following steps:

[0049] Step 1: As Figure 1 As shown, the three-phase current i detected by the permanent magnet synchronous motor is taken. a i b i c The current i in the two-phase stationary coordinate system is obtained by Clark transformation. α i β As shown in the following formula:

[0050]

[0051] Step 2: Perform an inverse Park transformation on the output of the current loop to calculate the voltage u in the two-phase stationary coordinate system. α u β The voltage equation for the motor is as follows:

[0052]

[0053] Where i α i β It is the current component of the stator current in a two-phase stationary coordinate system, R is the stator resistance, and ω is the current component. e It is the electric angular velocity of the motor rotor. It is the rotor permanent magnet flux linkage, L d L q These are the d-axis and q-axis inductance components in the dq-axis coordinate system, i d iq The current components along the d and q axes in the dq-axis coordinate system of the stator current, θ e It is the rotor position angle.

[0054] Step 3: Based on the voltage u in the two-phase stationary coordinate system α u β Sliding mode control function component z α z β and the observed values ​​of the electric angular velocity of the motor rotor The observed values ​​of the currents in the two-phase stationary coordinate system are calculated using a sliding mode observer. The specific implementation is as follows:

[0055] The voltage equations in the two-phase stationary coordinate system in step 2 are transformed into current equations in the two-phase stationary coordinate system, as shown in the following formula:

[0056]

[0057] Among them, e α_EXT e β_EXT Let be the components of the extended back electromotive force along the α-β axis, expressed as:

[0058]

[0059] Calculate the observed values ​​of the stator current.

[0060]

[0061] in, The observed value of the electric angular velocity of the motor rotor, z α z β These are the components of the sliding mode control function on the α-β axes.

[0062] Step 4: Calculate the current observation values ​​obtained in Step 3. With actual current i α i β The difference is input into the sliding mode control function to obtain the sliding mode control function component z. α z β The implementation method is as follows:

[0063]

[0064] in, Here, k represents the rotor position observation value, and k is the sliding mode gain coefficient. c This is the sliding mode gain correction factor, which is calculated as follows: Figure 2 As shown, To use rotor position observations The obtained motor dq-axis current, sgn is a sign function.

[0065] Construct a sliding mode observer using the above sliding mode control function:

[0066]

[0067] in, This is the error value between the observed current and the actual detected current;

[0068] When the observed current error is zero, the extended back electromotive force e in the two-phase stationary coordinate system is obtained by reconstructing it through the sliding mode control function. α_EXT e β_EXT .

[0069]

[0070] Step 5: Convert the sliding mode control function components z in the two-phase stationary coordinate system from Step 4. α z β Eliminating q-axis current coupling to obtain Its expression is:

[0071]

[0072] Step 6: Obtain the information from Step 5 The observed rotor angular velocity was extracted using an extended state observer-phase-locked loop. and rotor position angle And As input for steps 3 and 4, As input for steps 4 and 5. The specific implementation is as follows:

[0073] The principle block diagram of the extended state observer-phase-locked loop module is as follows: Figure 3 As shown. In a permanent magnet synchronous motor, the electrical angle θ of the motor... e Rotational speed ω e Angular acceleration a e The relationship between the angular jerk d and the angular jerk is:

[0074]

[0075] angular acceleration a e As the observed variable for the extended state, the extended state observer is constructed as follows:

[0076]

[0077] In the formula, z i and β i(i = 1, 2, 3) represent the state variables and the observer gain, respectively. The state variable z1 is the rotor electrical angle observed by the extended state observer-phase-locked loop module, z2 is the rotor speed, and z3 is the angular acceleration.

[0078] Applying the Laplace transform to the above equation yields the transfer function of the extended state observer-phase-locked loop module:

[0079]

[0080] The simulation waveforms of the sliding mode observer control function are shown in Figures 4(a) and 4(b). Figure 4(a) is a comparison between the traditional sliding mode control function after q-axis current decoupling and the reference back EMF, and Figure 4(b) is a comparison between the improved sliding mode control function after q-axis current decoupling and the reference back EMF. This shows that the waveform obtained by the proposed improved sliding mode control function after eliminating q-axis current coupling is close to the reference back EMF, with smaller fluctuation amplitude, higher sinusoidal intensity, and more accurate estimated position angle than the traditional sliding mode control function.

[0081] The simulation waveforms of the motor position observation error are shown in Figure 5(a) and Figure 5(b). Figure 5(a) shows the position error of the traditional sliding mode observer after q-axis current decoupling, and Figure 5(b) shows the position error of the improved sliding mode observer after q-axis current decoupling. This shows that the proposed improved sliding mode observer can improve the position observation accuracy, and then obtain accurate rotor position and speed estimates through the extended state observer-phase-locked loop.

[0082] This embodiment also provides a storage medium on which a computer program is stored, which, when executed by a processor, implements the electrolytic capacitor-free driving method.

[0083] An apparatus includes a memory, a processor, and the electrolytic capacitor-free driving method stored in the memory and operable on the processor.

[0084] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described above. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A sensorless, capacitor-free driving method based on position sensor-free control, characterized in that, include: Step 1: Convert the three-phase current i a i b i c The current i in the two-phase stationary coordinate system is obtained by Clark transformation. α i β ; Step 2: Perform an inverse Park transformation on the output of the current controller to calculate the voltage u in the two-phase stationary coordinate system. α u β ; Step 3: Based on the voltage u in the two-phase stationary coordinate system α u β Sliding mode control function component z α z β and the observed values ​​of the electric angular velocity of the motor rotor Calculate the current observations in the two-phase stationary coordinate system using a sliding mode observer. Step 4: Observe the two-phase quiescent current values With actual value i α i β The difference is input into the sliding mode control function to obtain the sliding mode control function components z in the two-phase stationary coordinate system. α z β ; Step 5: Convert the sliding mode control function components z in the two-phase stationary coordinate system obtained in Step 4. α z β After eliminating q-axis current coupling, we obtain Step 6: Obtain the information from Step 5 The observed rotor angular velocity and rotor position are reconstructed after the extended state observer-phase-locked loop. And As input for steps 3 and 4, As input for steps 4 and 5.

2. The electrolytic capacitor-free driving method according to claim 1, characterized in that, Perform an inverse Park transformation on the output of the current controller to calculate the voltage u in the two-phase stationary coordinate system. α u β The motor voltage equation is as follows: Where i α i β It is the stator current component in a two-phase stationary coordinate system, R is the stator resistance, and ω is the stator current component. e It is the electric angular velocity of the motor rotor. It is the rotor permanent magnet flux linkage, L d L q These are the d-axis and q-axis inductance components in the dq-axis coordinate system, i d i q θ represents the d-axis and q-axis current components in the dq-axis coordinate system. e It is the rotor position angle.

3. The electrolytic capacitor-free driving method according to claim 1, characterized in that, In step 3, based on the voltage u in the two-phase stationary coordinate system α u β Sliding mode control function component z α z β and the observed values ​​of the electric angular velocity of the motor rotor Calculate the current observations in the two-phase stationary coordinate system using a sliding mode observer. Implementation in, The observed value of the electric angular velocity of the motor rotor, z α z β These are the components of the sliding mode control function on the α-β axes.

4. The electrolytic capacitor-free driving method according to claim 1, characterized in that, In step 4, the current i in the two-phase stationary coordinate system is... α i β Compared with current observations The difference is processed by the sliding mode control function to obtain the sliding mode control function components z in the two-phase stationary coordinate system. α z β ; in, Here, k represents the rotor position observation value, and k is the sliding mode gain coefficient. c This is the sliding mode gain correction factor. To use rotor position angle observations The obtained motor dq-axis current, sgn is a sign function.

5. The electrolytic capacitor-free driving method according to claim 4, characterized in that, Construct a sliding mode observer using the above sliding mode control function: in, This is the error between the observed current value and the actual detected current; When the observed current error is zero, the extended back electromotive force in the two-phase stationary coordinate system can be reconstructed through the sliding mode control function:

6. The electrolytic capacitor-free driving method according to claim 1, characterized in that, Step 5: Convert the sliding mode control function components z in the two-phase stationary coordinate system from Step 4. α z β After eliminating q-axis current coupling, we obtain 7. The electrolytic capacitor-free driving method according to claim 1, characterized in that, The transfer function of the extended state observer-phase-locked loop is:

8. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the electrolytic capacitor-free driving method as described in any one of claims 1-7.

9. A device, characterized in that, It includes a memory, a processor, and a capacitorless driving method as described in any one of claims 1-7, which is stored on the memory and can be run on the processor.

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