Motor control system, control method thereof, motor, and storage medium

Abstract

The application discloses a motor control system and a control method thereof, a motor and a storage medium, and relates to the technical field of motor control systems. The motor control system comprises a complementary main high-level dead zone compensation module, a zero-crossing point judgment module and a voltage difference compensation module. The complementary main high-level dead zone compensation module calculates the error square wave voltage of an inverter and superimposes the error square wave voltage on an SVPWM modulation wave. The zero-crossing point judgment module judges whether the current output by the inverter is zero-crossing. The voltage difference compensation module generates a compensation voltage based on the ideal output voltage and the actual output voltage of the inverter when the current is zero-crossing, and superimposes the compensation voltage on the SVPWM modulation wave. According to the scheme, the error square wave voltage is used for dynamic compensation, and a compensation voltage is generated at the zero-crossing point to achieve accurate compensation, so that the dead zone compensation efficiency is optimized, the influence of the dead zone on the circuit is reduced, and the stability and reliability of the circuit are improved.

Description

Technical Field

[0001] This invention belongs to the field of motor control technology, specifically relating to a motor control system and its control method, a motor, and a storage medium. Background Technology

[0002] In high-frequency switching applications, the setting of dead time is crucial, directly impacting system efficiency and stability. Dead time is a manually set delay in the drive signal switching process to prevent short circuits caused by simultaneous conduction of upper and lower bridge arm power devices (such as IGBTs and MOSFETs). By introducing dead time into the drive signal and dynamically adjusting it according to the IGBT's operating state, simultaneous conduction of upper and lower bridge arms can be effectively avoided, thereby improving system safety.

[0003] Some solutions use complementary main high-level dead-time compensation, but since complementary main high-level dead-time compensation is an open-loop compensation method with a fixed dead-time compensation time, dynamic compensation is not possible, resulting in poor compensation efficiency and affecting circuit stability and reliability.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a motor control system and its control method, motor, and storage medium to solve the problem that the dead-time compensation time of the complementary main high-level dead-time compensation method in related solutions is a fixed time, which cannot perform dynamic compensation, resulting in poor compensation efficiency and affecting circuit stability and reliability. The invention achieves the effect of using error square wave voltage for dynamic compensation and generating compensation voltage at the zero-crossing point for accurate compensation, thereby optimizing dead-time compensation efficiency, reducing the impact of dead time on the circuit, and improving circuit stability and reliability.

[0006] This invention provides a motor control system, which includes an inverter. The motor control system comprises: a complementary main high-level dead-time compensation module for calculating the error square wave voltage of the inverter and superimposing it onto an SVPWM modulation wave; a zero-crossing point judgment module for determining whether the current output by the inverter crosses zero; and a voltage difference compensation module for generating a compensation voltage based on the ideal output voltage and the actual output voltage of the inverter when the current output by the inverter crosses zero, and superimposing it onto the SVPWM modulation wave. The ideal output voltage is the output voltage without dead time.

[0007] In some implementations, the complementary main high-level dead-time compensation module calculates the error square wave voltage of the inverter and superimposes it onto the SVPWM modulation wave, including: detecting the polarity of the three-phase output current of the inverter and calculating the error square wave voltage, the calculation formula being:

[0008]

[0009] Among them, U abu T is the error square wave voltage. d To preset the dead time, T s For the carrier period, U dc is the DC bus voltage; sgn(i) is the current polarity sign function. When the three-phase output current flows out of the inverter bridge arm, sgn(i) = 1, and when the three-phase output current flows into the inverter bridge arm, sgn(u) = -1.

[0010] The error square wave voltage is reverse-calculated, and the reverse-calculated error square wave voltage is superimposed on the SVPWM modulation wave; wherein, the calculation formula for the reverse-calculation of the error square wave voltage is:

[0011]

[0012] Among them, U mbu U is the error square wave voltage after reverse conversion. Δ U is the amplitude of the triangular carrier wave. dc This is the DC bus voltage.

[0013] In some implementations, the zero-crossing determination module determines whether the current output by the inverter crosses zero, including: continuously acquiring at least two output voltage values ​​of the inverter and determining the maximum output voltage and the minimum output voltage; determining whether the product of the maximum output voltage and the minimum output voltage is less than zero; if the product of the maximum output voltage and the minimum output voltage is not less than zero, then determining that the current does not cross zero; if the product of the maximum output voltage and the minimum output voltage is less than zero, then determining that the current crosses zero.

[0014] In some implementations, the voltage difference compensation module generates a compensation voltage superimposed on the SVPWM modulation wave based on the ideal output voltage and the actual output voltage of the inverter. This includes: acquiring the ideal output voltage and the actual output voltage; calculating the difference between the ideal output voltage and the actual output voltage; and generating the compensation voltage using the following formula:

[0015]

[0016] Among them, U bc To compensate for voltage, For the ideal output voltage, ΔUout U is the difference between the ideal output voltage and the actual output voltage. Δ This represents the amplitude of the triangular carrier wave.

[0017] In conjunction with the aforementioned motor control system, another aspect of the present invention provides a control method for a motor control system, the motor control system having an inverter; the method includes: calculating the error square wave voltage of the inverter and superimposing it onto an SVPWM modulation wave; determining whether the current output by the inverter crosses zero; when the current output by the inverter crosses zero, generating a compensation voltage based on the ideal output voltage and the actual output voltage of the inverter and superimposing it onto the SVPWM modulation wave; the ideal output voltage is the output voltage without dead time.

[0018] In some implementations, calculating the error square wave voltage of the inverter and superimposing it onto the SVPWM modulation wave includes: detecting the polarity of the three-phase output current of the inverter and calculating the error square wave voltage using the following formula:

[0019]

[0020] Among them, U abu T is the error square wave voltage. d To preset the dead time, T s For the carrier period, U dc is the DC bus voltage; sgn(i) is the current polarity sign function. When the three-phase output current flows out of the inverter bridge arm, sgn(i) = 1, and when the three-phase output current flows into the inverter bridge arm, sgn(i) = -1.

[0021] The error square wave voltage is reverse-calculated, and the reverse-calculated error square wave voltage is superimposed on the SVPWM modulation wave; wherein, the calculation formula for the reverse-calculation of the error square wave voltage is:

[0022]

[0023] Among them, U mbu U is the error square wave voltage after reverse conversion. Δ U is the amplitude of the triangular carrier wave. dc This is the DC bus voltage.

[0024] In some implementations, determining whether the current output by the inverter crosses zero includes: continuously acquiring at least two output voltage values ​​of the inverter and determining the maximum output voltage and the minimum output voltage; determining whether the product of the maximum output voltage and the minimum output voltage is less than zero; if the product of the maximum output voltage and the minimum output voltage is not less than zero, then determining that the current does not cross zero; if the product of the maximum output voltage and the minimum output voltage is less than zero, then determining that the current crosses zero.

[0025] In some implementations, a compensation voltage is generated and superimposed on the SVPWM modulation wave based on the ideal output voltage and the actual output voltage of the inverter. This includes: acquiring the ideal output voltage and the actual output voltage; calculating the difference between the ideal output voltage and the actual output voltage; and generating the compensation voltage. The formula for generating the compensation voltage is:

[0026]

[0027] Among them, U bc To compensate for voltage, For the ideal output voltage, ΔU out U is the difference between the ideal output voltage and the actual output voltage. Δ This represents the amplitude of the triangular carrier wave.

[0028] In conjunction with the above-described motor control system, the present invention further provides a motor comprising: the motor control system described above.

[0029] In conjunction with the above method, the present invention further provides a storage medium comprising a stored program, wherein, when the program is executed, the device on which the storage medium is located executes the control method of the motor control system described above.

[0030] The present invention provides a motor control system comprising a complementary high-level dead-time compensation module, a zero-crossing judgment module, and a voltage difference compensation module. The complementary high-level dead-time compensation module calculates the inverter's error square wave voltage and superimposes it onto the SVPWM modulation wave. The zero-crossing judgment module determines whether the inverter's output current has crossed zero. The voltage difference compensation module generates a compensation voltage based on the inverter's ideal and actual output voltages when the current crosses zero and superimposes it onto the SVPWM modulation wave. Thus, by utilizing the error square wave voltage for dynamic compensation and generating a compensation voltage at the zero-crossing point for precise compensation, the dead-time compensation efficiency is optimized, the impact of the dead-time on the circuit is reduced, and the circuit stability and reliability are improved.

[0031] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0032] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of an embodiment of the motor control system of the present invention;

[0034] Figure 2 This is a schematic flowchart of an embodiment of the control method for the motor control system of the present invention;

[0035] Figure 3 This is a structural block diagram of the motor control system of the present invention;

[0036] Figure 4 Schematic diagram for complementary master high-level dead zone compensation;

[0037] Figure 5 A flowchart illustrating the zero-crossing determination process. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0039] According to an embodiment of the present invention, a motor control system is provided. The motor control system includes an inverter. The motor control system employs dual closed-loop control (current loop and speed loop), and achieves decoupling of the d-axis and q-axis currents through coordinate transformation. The system exhibits excellent static and dynamic response characteristics. Specifically, as follows... Figure 3 As shown, the given value of the rotational speed ω * The DC flow rate setpoint i is obtained by comparing it with the actual rotational speed ω and then passing it through a PI controller. q * The output current i of the three-phase inverter a i b i c i is obtained after Clarke transformation α i β After undergoing the park transformation, i is obtained. d i q i q * with i q The comparison is then processed by a PI controller to obtain u. q i d * with i dThe comparison is obtained by the PI controller. d u d with u q u is obtained after Park's inverse transform α u β Then, by confirming the switching time of each sector, the conduction time of each bridge arm switch is obtained.

[0040] Specifically, the first step is speed loop control, with an input signal of ω. * Compared with the actual rotational speed ω, ω * The difference between ω and ω is adjusted by the speed loop PI controller, and the output DC quantity i is generated. q * Speed ​​deviation reflects changes in motor load; by increasing i q * This increases electromagnetic torque, enabling zero-steady-state-error speed regulation. Following this is current sampling and coordinate transformation, acquiring the inverter's output i... a i b i c The current in the three-phase stationary coordinate system is converted into its component i in the two-phase stationary coordinate system. α i β This eliminates the symmetry constraints of the three-phase system; then, a Park transformation is performed to convert the αβ-axis currents into DC components i in a synchronous rotating coordinate system. d i q To achieve i d and i q Decoupling.

[0041] Speed ​​loop control is followed by current loop control. The input signals for the inner loop PI regulation include the torque and current setpoint i output from the speed loop. q * Actual torque current i q Excitation current setpoint i d * Actual excitation current i d Output d-axis voltage setpoint u d q-axis voltage setpoint u q Then, an inverse coordinate transformation is performed to convert the dq-axis voltage u... d u q Converted to αβ axis voltage u α u β According to u α u βThe vector position determines the SVPWM sector in which it resides. The durations T1 and T2 of this vector's action on the two adjacent base voltage vectors within the sector are calculated. Combined with the duration T0 of the zero vector, the total switching period T = T0 + T1 + T2 is obtained. Based on the switching time distribution of each sector, the turn-on and turn-off times of the inverter's upper and lower bridge arm switches are calculated to drive power devices such as IGBTs and output the desired voltage vector.

[0042] The three-phase AC quantities are converted into DC quantities in a rotating coordinate system by coordinate transformation, thereby achieving decoupled control of excitation current and torque current, and finally driving the inverter through SVPWM modulation.

[0043] like Figure 1 As shown, the motor control system may include: a complementary master high-level dead zone compensation module, a zero-crossing point judgment module, and a voltage difference compensation module.

[0044] The complementary main high-level dead-time compensation module is used to calculate the error square wave voltage of the inverter and superimpose it onto the SVPWM modulation wave.

[0045] The complementary high-level dead-time compensation module performs compensation throughout the entire process, meaning that complementary high-level dead-time compensation is performed regardless of whether the inverter output current has crossed zero. The error square wave voltage is the output voltage error caused by the inverter's dead time. Essentially, it's a square wave signal synchronized with the current phase, used to dynamically adjust the SVPWM modulation wave to compensate for voltage distortion caused by the dead time. The SVPWM modulation wave is the core signal used to control the on / off switching of the inverter bridge arm switches; its function is to convert the voltage vector required for motor control into an actual executable pulse sequence. The compensation voltage, calculated using current polarity and system parameters, is used to counteract the impact of dead time on the output voltage.

[0046] In some implementations, the complementary main high-level dead-time compensation module calculates the error square wave voltage of the inverter and superimposes it onto the SVPWM modulation wave, including:

[0047] The polarity of the three-phase output current of the inverter is detected, and the error square wave voltage is calculated using the following formula:

[0048]

[0049] Among them, U abu T is the error square wave voltage. d The preset dead time is a fixed parameter, T. s For the carrier period, U dc is the DC bus voltage; sgn(i) is the current polarity sign function. When the three-phase output current flows out of the inverter bridge arm, sgn(i) = 1, and when the three-phase output current flows into the inverter bridge arm, sgn(i) = -1.

[0050] Detecting the polarity of the three-phase output current of the inverter includes the polarity of the current in phase A, phase B, and phase C. Taking phase A as an example, when the current flows out of the bridge arm, i... a >0, at this time sgn(i a ) = 1; when current flows into the bridge arm, i a <0, at this time sgn(i a = -1. This allows the compensation amount to be dynamically adjusted according to the direction of the current.

[0051] The error square wave voltage is reverse-calculated, and the reverse-calculated error square wave voltage is superimposed on the SVPWM modulation wave. The calculation formula for the reverse-calculation of the error square wave voltage is as follows:

[0052]

[0053] Among them, U mbu U is the error square wave voltage after reverse conversion. Δ U is the amplitude of the triangular carrier wave. dc This is the DC bus voltage.

[0054] According to the modulation principle of SPWM, the modulation voltage and the output voltage have the following relationship:

[0055]

[0056] In the above formula, U m U is the modulation amplitude value. △ U is the amplitude of the triangular carrier wave. dc U is the DC bus voltage. out This is the output voltage.

[0057] When U abu When superimposed on the waveform of the SVPWM modulation output, it needs to be reverse-calculated. The compensation voltage after the calculation is as follows:

[0058]

[0059] Furthermore, unlike traditional dead-time compensation where the conduction times of the upper and lower bridge arms are completely opposite (i.e., the lower (upper) bridge arm is turned on when the upper (lower) bridge arm is turned on), the conduction times of the upper and lower bridge arms differ by 2T in complementary master high-level dead-time compensation. dead Therefore, when the upper bridge arm modulated voltage compensation U abu At the same time, the lower bridge arm also compensates for U. abu .like Figure 4 As shown, during the positive half-cycle, the rising edge of the high level is delayed by T. dead Low-level rising edge delay T dead The negative half-cycle is complementary and conducts.

[0060] By detecting the polarity of the inverter's three-phase output current, an error square wave voltage is dynamically generated and superimposed on the SVPWM modulation wave to compensate for the output voltage error caused by dead time. This avoids conduction delay of the upper and lower bridge arms due to dead time, reduces output voltage distortion, and optimizes circuit efficiency and reliability. Furthermore, the error voltage is evenly distributed across each switching cycle, avoiding compensation lag and making it suitable for high-frequency switching scenarios. The compensation voltage is in phase with the current, ensuring effective compensation of the dead time effect in both the positive and negative half-cycles of the current.

[0061] The zero-crossing detection module is used to determine whether the current output by the inverter crosses zero.

[0062] When the motor phase current crosses zero, the current polarity switches. At this point, the voltage error caused by the dead time exhibits nonlinearity and uncertainty. Conventional fixed compensation strategies struggle to accurately match the current change trend, easily leading to compensation lag or incorrect direction, resulting in increased output voltage harmonics and exacerbated torque ripple. Therefore, this solution corrects the polarity switching logic of the complementary main high-level dead-time compensation by judging the zero-crossing point, ensuring that the error square wave voltage is updated in a timely manner when the current polarity changes, thus achieving precise switching of the compensation amount.

[0063] In some implementations, the zero-crossing determination module determines whether the current output by the inverter crosses zero, including: continuously acquiring at least two output voltage values ​​of the inverter and determining the maximum output voltage and the minimum output voltage; determining whether the product of the maximum output voltage and the minimum output voltage is less than zero; if the product of the maximum output voltage and the minimum output voltage is not less than zero, then determining that the current does not cross zero; if the product of the maximum output voltage and the minimum output voltage is less than zero, then determining that the current crosses zero.

[0064] Specifically, such as Figure 5 As shown, the output voltage was continuously sampled 5 times and recorded as U in chronological order. out1 U out2 U out3 U out4 U out5 The maximum output voltage U is obtained by comparison. outmax With minimum output voltage U outmin Determine U outmax and Uoutmin The product U outmax ×U outmin If the product is greater than 0, then the point is not at a zero-crossing point; if the product is less than 0, then the point is at a zero-crossing point.

[0065] When it is determined that it is at a zero-crossing point, the maximum output voltage U is determined. outmax With minimum output voltage U outmin Which one was collected first in time, if Uoutmax If the data is collected earlier, it is at the zero-crossing point of the transition from the positive half-cycle to the negative half-cycle; otherwise, it is at the zero-crossing point of the transition from the negative half-cycle to the positive half-cycle.

[0066] The zero-crossing point determination result is used to correct the polarity switching logic of the complementary main high-level dead zone compensation, ensuring that the sign function sgn(i) of the error square wave voltage is updated in a timely manner when the current polarity changes, thus achieving accurate switching of the compensation amount. Near the zero-crossing point, the compensation intensity is further adjusted by calculating the difference between the ideal voltage and the actual voltage, forming a dual optimization mechanism of polarity determination + dynamic compensation to make up for the deficiencies of feedforward compensation.

[0067] The voltage difference compensation module is used to generate a compensation voltage superimposed on the SVPWM modulation wave based on the ideal output voltage and the actual output voltage of the inverter when the current output by the inverter crosses zero; the ideal output voltage is the output voltage without dead time.

[0068] The ideal output voltage is the voltage value that the inverter should output without considering dead time; that is, the theoretical voltage without the influence of dead time. It is calculated using a mathematical model of the motor control system and does not include voltage distortion caused by dead time.

[0069] like Figure 3 As shown, before the zero-crossing judgment stage, the complementary main high-level dead-time compensation serves as feedforward compensation. At the zero-crossing point, in addition to feedforward compensation, feedback compensation is also performed based on the difference between the ideal conditions and the output voltage with added dead time. This further corrects the dead-time effect, precisely controls the dead time, and optimizes the dead-time compensation efficiency. Feedforward compensation dynamically adjusts the compensation amount based on current polarity to cover the basic error of the dead time; feedback compensation corrects the remaining error of feedforward compensation based on the difference between the ideal and actual voltage, especially improving compensation accuracy under complex conditions such as zero-crossing.

[0070] In some implementations, the voltage difference compensation module generates a compensation voltage superimposed on the SVPWM modulation wave based on the ideal output voltage and the actual output voltage of the inverter, including:

[0071] Collect the ideal output voltage and the actual output voltage.

[0072] Calculate the difference between the ideal output voltage and the actual output voltage, and generate a compensation voltage. The formula for generating the compensation voltage is:

[0073]

[0074] Among them, U bc To compensate for voltage, For the ideal output voltage, ΔU outU is the difference between the ideal output voltage and the actual output voltage. Δ This represents the amplitude of the triangular carrier wave.

[0075] The calculation of the difference between the ideal output voltage and the dead-time output voltage is the feedback correction stage of the dead-time compensation strategy. Its core is to dynamically optimize the compensation amount through real-time voltage error. The ideal output voltage refers to the voltage that the inverter should theoretically output without a dead time. The actual output voltage refers to the actual output voltage of the inverter after a dead time is added during operation, which can be obtained through real-time sampling by a voltage sensor. Calculating the ideal output voltage... With the actual output voltage U out The difference ΔU out , This difference reflects the degree of voltage distortion caused by the dead time. A compensation voltage is then generated based on this difference and a calculation formula. This formula dynamically adjusts the compensation intensity through a proportional relationship to ensure that the compensation voltage matches the modulation wave characteristics, thus achieving closed-loop correction of the dead time effect.

[0076] By generating a compensation voltage at the zero-crossing point to perform compensation, a closed-loop feedback is formed to dynamically correct the error that is not offset by the feedforward compensation. This achieves full-cycle dynamic optimization of the dead-time effect, optimizes the dead-time compensation efficiency, improves the dead-time compensation accuracy, and reduces the impact of the dead-time on the circuit.

[0077] The motor control system using the technical solution of this embodiment includes a complementary main high-level dead-time compensation module, a zero-crossing judgment module, and a voltage difference compensation module. The complementary main high-level dead-time compensation module calculates the inverter's error square wave voltage and superimposes it onto the SVPWM modulation wave. The zero-crossing judgment module determines whether the inverter's output current has crossed zero. When the current crosses zero, the voltage difference compensation module generates a compensation voltage based on the inverter's ideal output voltage and actual output voltage and superimposes it onto the SVPWM modulation wave. Thus, by utilizing the error square wave voltage for dynamic compensation and generating a compensation voltage at the zero-crossing point for precise compensation, the dead-time compensation efficiency is optimized, the impact of the dead time on the circuit is reduced, and the circuit stability and reliability are improved.

[0078] According to an embodiment of the present invention, a control method for a motor control system is also provided. The motor control system includes an inverter. The motor control system employs dual closed-loop control (current loop and speed loop), and achieves decoupling of the d-axis and q-axis currents through coordinate transformation. The system exhibits excellent static and dynamic response characteristics. Specifically, as follows... Figure 3 As shown, the given value of the rotational speed ω * The DC flow rate setpoint i is obtained by comparing it with the actual rotational speed ω and then passing it through a PI controller. q * The output current i of the three-phase inverter a i b i ci is obtained after Clarke transformation α i β After undergoing the park transformation, i is obtained. d i q i q * with i q The comparison is then processed by a PI controller to obtain u. q i d * with i d The comparison is obtained by the PI controller. d u d with u q u is obtained after Park's inverse transform α u β Then, by confirming the switching time of each sector, the conduction time of each bridge arm switch is obtained.

[0079] Specifically, the first step is speed loop control, with an input signal of ω. * Compared with the actual rotational speed ω, ω * The difference between ω and ω is adjusted by the speed loop PI controller, and the output DC quantity i is generated. q * Speed ​​deviation reflects changes in motor load; by increasing i q * This increases electromagnetic torque, enabling zero-steady-state-error speed regulation. Following this is current sampling and coordinate transformation, acquiring the inverter's output i... a i b i c The current in the three-phase stationary coordinate system is converted into its component i in the two-phase stationary coordinate system. α i β This eliminates the symmetry constraints of the three-phase system; then, a Park transformation is performed to convert the αβ-axis currents into DC components i in a synchronous rotating coordinate system. d i q To achieve i d and i q Decoupling.

[0080] Speed ​​loop control is followed by current loop control. The input signals for the inner loop PI regulation include the torque and current setpoint i output from the speed loop. q * Actual torque current i q Excitation current setpoint i d * Actual excitation current i d Output d-axis voltage setpoint u d q-axis voltage setpoint u q Then, an inverse coordinate transformation is performed to convert the dq-axis voltage u... d uq Converted to αβ axis voltage u α u β According to u α u β The vector position determines the SVPWM sector in which it resides. The durations T1 and T2 of this vector's action on the two adjacent base voltage vectors within the sector are calculated. Combined with the duration T0 of the zero vector, the total switching period T = T0 + T1 + T2 is obtained. Based on the switching time distribution of each sector, the turn-on and turn-off times of the inverter's upper and lower bridge arm switches are calculated to drive power devices such as IGBTs and output the desired voltage vector.

[0081] The three-phase AC quantities are converted into DC quantities in a rotating coordinate system by coordinate transformation, thereby achieving decoupled control of excitation current and torque current, and finally driving the inverter through SVPWM modulation.

[0082] See Figure 2 As shown, the control method of the motor control system may include steps S110 to S130.

[0083] In step S110, the error square wave voltage of the inverter is calculated and superimposed on the SVPWM modulation wave.

[0084] Complementary high-level dead-time compensation is performed throughout the entire process, meaning it occurs regardless of whether the inverter's output current has crossed zero. The error square wave voltage represents the output voltage error caused by the inverter's dead time. Essentially, it's a square wave signal synchronized with the current phase, used to dynamically adjust the SVPWM modulation wave and compensate for voltage distortion caused by the dead time. The compensation voltage, calculated using current polarity and system parameters, is used to counteract the impact of the dead time on the output voltage.

[0085] In some implementations, step S110, calculating the error square wave voltage of the inverter and superimposing it onto the SVPWM modulation wave, includes:

[0086] The polarity of the three-phase output current of the inverter is detected, and the error square wave voltage is calculated using the following formula:

[0087]

[0088] Among them, U abu T is the error square wave voltage. d The preset dead time is a fixed parameter, T. s For the carrier period, U dc is the DC bus voltage; sgn(i) is the current polarity sign function. When the three-phase output current flows out of the inverter bridge arm, sgn(i) = 1, and when the three-phase output current flows into the inverter bridge arm, sgn(i) = -1.

[0089] Detecting the polarity of the three-phase output current of the inverter includes the polarity of the current in phase A, phase B, and phase C. Taking phase A as an example, when the current flows out of the bridge arm, i... a >0, at this time sgn(i a ) = 1; when current flows into the bridge arm, i a <0, at this time sgn(i a = -1. This allows the compensation amount to be dynamically adjusted according to the direction of the current.

[0090] The error square wave voltage is reverse-calculated, and the reverse-calculated error square wave voltage is superimposed on the SVPWM modulation wave. The calculation formula for the reverse-calculation of the error square wave voltage is as follows:

[0091]

[0092] Among them, U mbu U is the error square wave voltage after reverse conversion. Δ U is the amplitude of the triangular carrier wave. dc This is the DC bus voltage.

[0093] According to the modulation principle of SPWM, the modulation voltage and the output voltage have the following relationship:

[0094]

[0095] In the above formula, U m U is the modulation amplitude value. △ U is the amplitude of the triangular carrier wave. dc U is the DC bus voltage. out This is the output voltage.

[0096] When U abu When superimposed on the waveform of the SVPWM modulation output, it needs to be reverse-calculated. The compensation voltage after the calculation is as follows:

[0097]

[0098] Furthermore, unlike traditional dead-time compensation where the conduction times of the upper and lower bridge arms are completely opposite (i.e., the lower (upper) bridge arm is turned on when the upper (lower) bridge arm is turned on), the conduction times of the upper and lower bridge arms differ by 2T in complementary master high-level dead-time compensation. dead Therefore, when the upper bridge arm modulated voltage compensation U abu At the same time, the lower bridge arm also compensates for U. abu .like Figure 4 As shown, during the positive half-cycle, the rising edge of the high level is delayed by T. dead Low-level rising edge delay T dead The negative half-cycle is complementary and conducts.

[0099] By detecting the polarity of the inverter's three-phase output current, an error square wave voltage is dynamically generated and superimposed on the SVPWM modulation wave to compensate for the output voltage error caused by dead time. This avoids conduction delay of the upper and lower bridge arms due to dead time, reduces output voltage distortion, and optimizes circuit efficiency and reliability. Furthermore, the error voltage is evenly distributed across each switching cycle, avoiding compensation lag and making it suitable for high-frequency switching scenarios. The compensation voltage is in phase with the current, ensuring effective compensation of the dead time effect in both the positive and negative half-cycles of the current.

[0100] In step S120, it is determined whether the current output by the inverter has crossed zero.

[0101] When the motor phase current crosses zero, the current polarity switches. At this point, the voltage error caused by the dead time exhibits nonlinearity and uncertainty. Conventional fixed compensation strategies struggle to accurately match the current change trend, easily leading to compensation lag or incorrect direction, resulting in increased output voltage harmonics and exacerbated torque ripple. Therefore, this solution corrects the polarity switching logic of the complementary main high-level dead-time compensation by judging the zero-crossing point, ensuring that the error square wave voltage is updated in a timely manner when the current polarity changes, thus achieving precise switching of the compensation amount.

[0102] In some implementations, step S120, determining whether the current output by the inverter crosses zero, includes: continuously acquiring at least two output voltage values ​​of the inverter and determining the maximum output voltage and the minimum output voltage; determining whether the product of the maximum output voltage and the minimum output voltage is less than zero; if the product of the maximum output voltage and the minimum output voltage is not less than zero, then determining that the current does not cross zero; if the product of the maximum output voltage and the minimum output voltage is less than zero, then determining that the current crosses zero.

[0103] Specifically, such as Figure 5 As shown, the output voltage was continuously sampled 5 times and recorded as U in chronological order. out1 U out2 U out3 U out4 U out5 The maximum output voltage U is obtained by comparison. outmax With minimum output voltage U outmin Determine U outmax and Uoutmin The product U outmax ×U outmin If the product is greater than 0, then the point is not at a zero-crossing point; if the product is less than 0, then the point is at a zero-crossing point.

[0104] When it is determined that it is at a zero-crossing point, the maximum output voltage U is determined. outmax With minimum output voltage U outmin Which one was collected first in time, if Uoutmax If the data is collected earlier, it is at the zero-crossing point of the transition from the positive half-cycle to the negative half-cycle; otherwise, it is at the zero-crossing point of the transition from the negative half-cycle to the positive half-cycle.

[0105] The zero-crossing point determination result is used to correct the polarity switching logic of the complementary main high-level dead zone compensation, ensuring that the sign function sgn(i) of the error square wave voltage is updated in a timely manner when the current polarity changes, thus achieving accurate switching of the compensation amount. Near the zero-crossing point, the compensation intensity is further adjusted by calculating the difference between the ideal voltage and the actual voltage, forming a dual optimization mechanism of polarity determination + dynamic compensation to make up for the deficiencies of feedforward compensation.

[0106] At step S130, when the current output by the inverter crosses zero, a compensation voltage is generated and superimposed on the SVPWM modulation wave based on the ideal output voltage and the actual output voltage of the inverter; the ideal output voltage is the output voltage without dead time.

[0107] The ideal output voltage is the voltage value that the inverter should output without considering dead time; that is, the theoretical voltage without the influence of dead time. It is calculated using a mathematical model of the motor control system and does not include voltage distortion caused by dead time.

[0108] like Figure 3 As shown, before the zero-crossing judgment stage, the complementary main high-level dead-time compensation serves as feedforward compensation. At the zero-crossing point, in addition to feedforward compensation, feedback compensation is also performed based on the difference between the ideal conditions and the output voltage with added dead time. This further corrects the dead-time effect, precisely controls the dead time, and optimizes the dead-time compensation efficiency. Feedforward compensation dynamically adjusts the compensation amount based on current polarity to cover the basic error of the dead time; feedback compensation corrects the remaining error of feedforward compensation based on the difference between the ideal and actual voltage, especially improving compensation accuracy under complex conditions such as zero-crossing.

[0109] In some implementations, step S130, based on the ideal output voltage and the actual output voltage of the inverter, generates a compensation voltage superimposed on the SVPWM modulation wave, including:

[0110] Collect the ideal output voltage and the actual output voltage.

[0111] Calculate the difference between the ideal output voltage and the actual output voltage, and generate a compensation voltage. The formula for generating the compensation voltage is:

[0112]

[0113] Among them, U bc To compensate for voltage, For the ideal output voltage, ΔU outU is the difference between the ideal output voltage and the actual output voltage. Δ This represents the amplitude of the triangular carrier wave.

[0114] The calculation of the difference between the ideal output voltage and the dead-time output voltage is the feedback correction stage of the dead-time compensation strategy. Its core is to dynamically optimize the compensation amount through real-time voltage error. The ideal output voltage refers to the voltage that the inverter should theoretically output without a dead time. The actual output voltage refers to the actual output voltage of the inverter after a dead time is added during operation, which can be obtained through real-time sampling by a voltage sensor. Calculating the ideal output voltage... With the actual output voltage U out The difference ΔU out , This difference reflects the degree of voltage distortion caused by the dead time. A compensation voltage is then generated based on this difference and a calculation formula. This formula dynamically adjusts the compensation intensity through a proportional relationship to ensure that the compensation voltage matches the modulation wave characteristics, thus achieving closed-loop correction of the dead time effect.

[0115] By generating a compensation voltage at the zero-crossing point to perform compensation, a closed-loop feedback is formed to dynamically correct the error that is not offset by the feedforward compensation. This achieves full-cycle dynamic optimization of the dead-time effect, optimizes the dead-time compensation efficiency, improves the dead-time compensation accuracy, and reduces the impact of the dead-time on the circuit.

[0116] Since the processing and functions implemented by the method in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned system, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0117] The technical solution of this invention includes a complementary main high-level dead-time compensation module, a zero-crossing judgment module, and a voltage difference compensation module. The complementary main high-level dead-time compensation module calculates the inverter's error square wave voltage and superimposes it onto the SVPWM modulation wave. The zero-crossing judgment module determines whether the inverter's output current has crossed zero. The voltage difference compensation module generates a compensation voltage based on the inverter's ideal and actual output voltages when the current crosses zero and superimposes it onto the SVPWM modulation wave. Thus, by utilizing the error square wave voltage for dynamic compensation and generating a compensation voltage at the zero-crossing point for precise compensation, the dead-time compensation efficiency is optimized, the impact of the dead-time on the circuit is reduced, and the circuit stability and reliability are improved.

[0118] According to an embodiment of the present invention, a motor corresponding to a motor control system is also provided. This motor may include the motor control system described above.

[0119] Since the processing and functions implemented by the motor in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned system, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0120] The technical solution of this invention includes a complementary main high-level dead-time compensation module, a zero-crossing judgment module, and a voltage difference compensation module. The complementary main high-level dead-time compensation module calculates the inverter's error square wave voltage and superimposes it onto the SVPWM modulation wave. The zero-crossing judgment module determines whether the inverter's output current has crossed zero. The voltage difference compensation module generates a compensation voltage based on the inverter's ideal and actual output voltages when the current crosses zero and superimposes it onto the SVPWM modulation wave. Thus, by utilizing the error square wave voltage for dynamic compensation and generating a compensation voltage at the zero-crossing point for precise compensation, the dead-time compensation efficiency is optimized, the impact of the dead-time on the circuit is reduced, and the circuit stability and reliability are improved.

[0121] According to an embodiment of the present invention, a storage medium corresponding to a control method for a motor control system is also provided. The storage medium includes a stored program, wherein the program, when running, controls the device where the storage medium is located to execute the control method for the motor control system described above.

[0122] Since the processing and functions implemented by the storage medium in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0123] The technical solution of this invention includes a complementary main high-level dead-time compensation module, a zero-crossing judgment module, and a voltage difference compensation module. The complementary main high-level dead-time compensation module calculates the inverter's error square wave voltage and superimposes it onto the SVPWM modulation wave. The zero-crossing judgment module determines whether the inverter's output current has crossed zero. The voltage difference compensation module generates a compensation voltage based on the inverter's ideal and actual output voltages when the current crosses zero and superimposes it onto the SVPWM modulation wave. Thus, by utilizing the error square wave voltage for dynamic compensation and generating a compensation voltage at the zero-crossing point for precise compensation, the dead-time compensation efficiency is optimized, the impact of the dead-time on the circuit is reduced, and the circuit stability and reliability are improved.

[0124] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0125] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of the claims.

Claims

1. A motor control system, characterized in that, The motor control system includes an inverter; The motor control system includes: The complementary main high-level dead-time compensation module is used to calculate the error square wave voltage of the inverter and superimpose it onto the SVPWM modulation wave. Specifically, it includes: performing a reverse calculation on the error square wave voltage, and superimposing the reverse-calculated error square wave voltage onto the SVPWM modulation wave; wherein the calculation formula for the reverse calculation of the error square wave voltage is: ； in, The error square wave voltage, This is the error square wave voltage after reverse conversion. The amplitude of the triangular carrier wave. This is the DC bus voltage; The zero-crossing detection module is used to determine whether the current output by the inverter crosses zero. The voltage difference compensation module is used to generate a compensation voltage superimposed on the SVPWM modulation wave based on the ideal output voltage and the actual output voltage of the inverter when the current output by the inverter crosses zero; the ideal output voltage is the output voltage without dead time. The voltage difference compensation module generates a compensation voltage superimposed on the SVPWM modulation wave based on the ideal output voltage and the actual output voltage of the inverter, including: Collect ideal output voltage and actual output voltage; Calculate the difference between the ideal output voltage and the actual output voltage, and generate a compensation voltage; the formula for generating the compensation voltage is: ； in, To compensate for voltage, For ideal output voltage, The difference between the ideal output voltage and the actual output voltage. This represents the amplitude of the triangular carrier wave.

2. The motor control system according to claim 1, characterized in that, The complementary main high-level dead-time compensation module calculates the error square wave voltage of the inverter, including: The polarity of the three-phase output current of the inverter is detected, and the error square wave voltage is calculated using the following formula: ； in, The error square wave voltage, To preset the dead time, For the carrier period, This is the DC bus voltage; This is a function representing the sign of the current polarity when the three-phase output current flows out of the inverter bridge arm. When the three-phase output current flows into the inverter bridge arm .

3. A control method for a motor control system, characterized in that, The motor control system includes an inverter; the method includes: Calculating the error square wave voltage of the inverter and superimposing it onto the SVPWM modulation wave specifically includes: performing a reverse calculation on the error square wave voltage, and superimposing the reverse-calculated error square wave voltage onto the SVPWM modulation wave; wherein, the calculation formula for the reverse calculation of the error square wave voltage is: ； in, The error square wave voltage, This is the error square wave voltage after reverse conversion. The amplitude of the triangular carrier wave. This is the DC bus voltage; Determine whether the current output by the inverter crosses zero; When the current output by the inverter crosses zero, a compensation voltage is generated and superimposed on the SVPWM modulation wave based on the ideal output voltage and the actual output voltage of the inverter; the ideal output voltage is the output voltage without dead time. Specifically, based on the ideal output voltage and the actual output voltage of the inverter, a compensation voltage is generated and superimposed on the SVPWM modulation wave, including: Collect ideal output voltage and actual output voltage; Calculate the difference between the ideal output voltage and the actual output voltage, and generate a compensation voltage; the formula for generating the compensation voltage is: ； in, To compensate for voltage, For ideal output voltage, The difference between the ideal output voltage and the actual output voltage. This represents the amplitude of the triangular carrier wave.

4. The control method for the motor control system according to claim 3, characterized in that, The calculation of the error square wave voltage of the inverter includes: The polarity of the three-phase output current of the inverter is detected, and the error square wave voltage is calculated using the following formula: ； in, The error square wave voltage, To preset the dead time, For carrier period, This is the DC bus voltage; This is a function representing the sign of the current polarity when the three-phase output current flows out of the inverter bridge arm. When the three-phase output current flows into the inverter bridge arm .

5. An electric motor, characterized in that, include: The motor control system as described in any one of claims 1 to 2.

6. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the control method of the motor control system as described in any one of claims 3 to 4.

Images