Air conditioner compressor rotating speed smooth switching control method and system based on coordinate transformation

Abstract

The application belongs to the technical field of motor control, and relates to a kind of air conditioner compressor rotating speed smooth switching control method and system based on coordinate transformation, and the electric angle is accurately constructed based on rotating speed integral limiting in low speed stage, and instantaneous switching is relied on coordinate transformation, and the instantaneous mapping of virtual coordinate system to actual motor rotor rotating coordinate system is realized by angle error constraint, and the range limitation of angle deviation is matched to avoid angle jump. At the same time, after switching, the rotating speed-current double closed loop control is quickly carried out, the torque ripple and current impact at switching moment are effectively inhibited, the smooth transition of open loop starting to closed loop operation is realized without impact, and the running stability of air conditioner compressor is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of motor control technology, and relates to air conditioning compressor control technology. Specifically, it relates to a method and system for smooth switching control of air conditioning compressor speed based on coordinate transformation. Background Technology

[0002] Permanent-magnetic synchronous motors (PMSMs) are widely used in applications requiring high dynamic performance and efficiency, such as air conditioning compressors, due to their high power density, miniaturization, and high efficiency. High-performance motor vector closed-loop control typically requires precise rotor position and speed information to achieve real-time closed-loop regulation of motor torque and flux linkage. Traditionally, this position information is obtained through position sensors such as encoders, resolvers, or Hall effect sensors. While position sensors can directly provide high-precision position and speed measurements, their use also introduces several problems: firstly, it increases system hardware costs and wiring complexity; secondly, the reliability and lifespan of sensors and their signal processing circuits are limited in harsh environments such as high temperatures, vibration, and electromagnetic interference; and thirdly, long lead-out lines introduce additional interference, requiring more complex anti-interference designs and filtering circuits.

[0003] Air conditioning compressor motor control systems equipped with position sensors have inherent shortcomings in terms of overall cost control and operational reliability improvement. On the one hand, to reduce costs and improve system robustness, the industry has proposed sensorless control methods, which estimate rotor position and speed using motor voltage and current information. Based on the operating speed range, existing sensorless position observation methods can be broadly divided into two categories: high-frequency signal injection methods suitable for zero-speed or low-speed conditions, and methods based on electromagnetic models or observers (such as extended Kalman filters, phase-locked loops, robust observers, etc.) suitable for medium-to-high-speed conditions. High-frequency injection methods suitable for zero-speed or low-speed conditions have significant drawbacks: First, this method places higher demands on the bandwidth of the current sensor and the computing power of the main control chip, requiring a higher bandwidth current sensor and a faster computing power main control chip, thus increasing hardware costs; second, the high-frequency noise generated by the high-frequency signal injection can easily interfere with the control system and peripheral equipment, requiring additional filtering circuits and anti-interference designs, further increasing hardware architecture complexity and R&D costs. On the other hand, to simplify the low-speed starting process and avoid the drawbacks of high-frequency injection, the industry and academia have introduced traditional induction motor starting strategies into the starting control scenario of PMSMs, with constant voltage-frequency ratio control being a typical application. Constant voltage-frequency ratio control, under dual open-loop conditions of current and speed, adjusts the output voltage according to a preset voltage-frequency ratio to drive the rotor to smoothly increase speed. However, this control method has several drawbacks in practical applications: First, when the slope of voltage and frequency changes is not properly matched, it can easily cause current oscillations, or even motor step loss. Second, under complex conditions of load changes or high frictional resistance, dual open-loop control of current and speed cannot achieve current or torque control constraints, leading to starting failure; excessive inrush current can exacerbate stress losses in electrical components. Third, when the system switches to closed-loop control, if the current and load torque deviate significantly during the open-loop period, torque pulsation or overcurrent will occur at the moment of switching, seriously affecting the motor's operational stability and the safety of the entire equipment.

[0004] To overcome the problems of constant voltage-frequency ratio control, current-frequency control has been proposed as an alternative starting strategy and applied to sensorless starting scenarios in PMSMs. Unlike constant voltage-frequency ratio control, current-frequency control employs closed-loop current regulation simultaneously with a given frequency, thereby limiting current overshoot and improving disturbance rejection. Current-frequency control utilizes the current closed loop and the motor's self-stabilizing characteristics (the interaction between torque and power angle) to achieve smooth starting, offering advantages such as simple adjustment and good disturbance rejection. Although current-frequency control has advantages over constant voltage-frequency ratio control in reducing starting current overshoot, it still has shortcomings in switching robustness, parameter configurability, and applicability to light loads.

[0005] In summary, existing technologies have significant shortcomings in sensorless PMSM starting and open-loop / closed-loop switching control: First, the low-speed high-frequency signal injection method has limited scope, requires high bandwidth for filters and current sensors, increases costs, and the position observation accuracy decreases with increasing speed. Second, for industrial equipment such as fans, pumps, and air conditioning compressors, their operating conditions are mainly medium-to-high speed operation, with fewer low-speed operation conditions. The requirements for low-speed performance and efficiency are relatively relaxed, and cost is a concern, so high-frequency injection methods are unnecessary. Third, constant voltage-frequency ratio control has the advantages of simple structure and ease of implementation, but due to the dual control of current and speed open loops, it lacks effective current constraints, easily leading to faults such as current oscillation and motor step loss, affecting starting reliability. Fourth, in current-frequency control, current controllability during the starting phase is achieved through current closed loop and speed open loop, with performance superior to constant voltage-frequency ratio control. However, switching to speed closed loop relies on empirical parameter tuning (e.g., virtual...). Fifth, the sensorless PMSM control system suffers from problems such as complex parameter calculation, large workload for on-site debugging, and insufficient system robustness, which restrict the large-scale promotion and engineering application of the sensorless PMSM control system in the industrial field.

[0006] Based on the aforementioned technical pain points, there is an urgent need in industrial applications for a sensorless air conditioning compressor switching control method with a simple structure and easily determined parameters. This method should enable the air conditioning compressor PMSM to start smoothly under various load conditions without relying on additional position sensors, and should reliably transition from speed open-loop control to speed closed-loop control, reducing current and torque fluctuations during the switching process and improving the overall practicality and engineering robustness of the system. Summary of the Invention

[0007] To address the aforementioned problems in existing technologies, this invention provides a method and system for smooth switching control of air conditioning compressor speed based on coordinate transformation. This method enables reliable starting over a wide load range (from no-load to heavy-load) and allows for smooth and stable switching to speed closed-loop field-oriented control at appropriate times, balancing cost, reliability, and robust control performance.

[0008] In a first aspect, the present invention provides a method for smooth switching control of air conditioning compressor speed based on coordinate transformation, comprising: Zero-speed start-up angle generation steps: based on mechanical speed reset signal For the rate of change of speed during startup Integral limiting determines the mechanical speed at startup. Based on the mechanical speed at startup and setting the allowed switching speed of the mechanical parts The size of the signal determines the trigger signal for the switching moment. ;Mechanical speed at startup After proportional and integral limiting, the starting electrical angle is generated by taking the modulus. ; Rotor angle processing steps: based on the trigger signal at the switching moment According to the electric angle at startup Electrical angle of motor rotor position Obtain the electrical angle of the coordinate transformation ; Electrical angle during startup Electrical angle with motor rotor position The difference is used to limit the angle range to obtain the angle error value. ; Current transformation steps: Based on coordinate transformation of electrical angles Convert the three-phase motor current into Shaft motor current; Instantaneous switching steps for coordinate transformation: based on angle error value and the trigger signal for switching time ,Will The shaft reference voltage is transformed into a rotating coordinate system corresponding to the actual rotor position of the motor at the switching moment. Shaft initial reference voltage and Shaft initial reference voltage And will set virtual Shaft starting current Convert to the rotating coordinate system corresponding to the actual rotor position of the motor at the switching moment. Shaft initial reference current and Shaft initial reference current ; Speed ​​control steps: Based on the trigger signal at the switching time Reference command for setting speed With the actual angular velocity of the motor Speed ​​error After scaling, integrating, and limiting, we obtain... Shaft current command ,according to Shaft current command and setting virtual Shaft starting current The size is obtained Shaft reference current ; Current control steps: based on the trigger signal at the switching time According to the instantaneous switch Axis current descent slope and Shaft initial reference current get Shaft reference current ,right Shaft reference current and Shaft motor current of Shaft current error After scaling, integrating, and limiting, we obtain... Shaft reference voltage Trigger signal based on switching time ,right Shaft reference current and Shaft motor current of Shaft current error After scaling, integrating, and limiting, we obtain... Shaft reference voltage ; Modulated wave generation steps: Based on coordinate transformation electrical angle ,Will Convert the shaft reference voltage to a three-phase reference voltage; Shaft reference voltage square plus Shaft reference voltage The square of the phase voltage amplitude is obtained by taking the square root of the square of the phase voltage amplitude. Based on phase voltage amplitude and DC bus voltage Generation voltage modulation ratio Based on three-phase reference voltage and phase voltage amplitude and voltage modulation ratio Generate a three-phase voltage modulation wave; Pulse width modulation steps: Based on the magnitude of the three-phase voltage modulation wave and the set triangular carrier wave, the drive signal of the power switching device in the air conditioner compressor motor drive circuit is generated.

[0009] In conjunction with the first aspect, in some embodiments, the mechanical speed at startup is obtained in the zero-speed start-up angle generation step. The methods include: If the mechanical speed reset signal When the level is high, it will affect the rate of change of speed during startup. The first integrator of the integral limiting is reset, and the output of the first integrator is reset to 0. After the reset is completed, the rate of change of speed during startup is calculated using the first integrator. The mechanical speed at startup is obtained by integral limiting. ; Generate trigger signal at the switching moment The methods include: Compare the mechanical speed at startup and setting the allowed switching speed of the mechanical parts Size; Mechanical speed at startup Greater than or equal to the set allowable mechanical speed for switching And when the delay is set through the delay module, the trigger signal for the switching time is... Set to 1; otherwise, the trigger signal for switching times. Set to 0; Generating the starting electrical angle The methods include: Mechanical speed at startup The starting electric angular velocity is obtained by multiplying by a proportional coefficient. ; Electric angular velocity at startup Integral limiting yields the starting potential angle Based on electrical angle reset signal The electric angular velocity at startup The second integrator of the integral limiting circuit is reset, and the starting potential angle is adjusted. Reset is to reset electrical angle Reset electrical angle Values ​​that change over time; The starting potential angle After investigation The starting electrical angle is obtained by taking the model. .

[0010] In conjunction with the first aspect, in some embodiments, the coordinate transformation electrical angle is obtained in the rotor angle processing step. The methods include: coordinate transformation electrical angle during startup. Electrical angle at startup The trigger signal at the switching time When the value is 1, its rising edge will transform the coordinates by electrical angle. Updated to motor rotor position electrical angle ; Obtain the angle error value The methods include: Determine the electric angle at startup Electrical angle with motor rotor position The difference Is it greater than ; If the difference Greater than To obtain the intermediate value The difference minus If the difference Less than or equal to To obtain the intermediate value The difference ; Determine the median value Is it less than ; If the median value Less than The angle error value is obtained. The median value Plus If the median value Greater than or equal to The angle error value is obtained. The median value .

[0011] In conjunction with the first aspect, in some embodiments, the three-phase motor current is converted into... Methods for controlling shaft motor current include: Phase motor current take reduce Phase motor current take Subtract again Phase motor current take ,get Shaft motor current ; Phase motor current multiplied reduce Phase motor current multiplied ,get Shaft motor current ; Shaft motor current Carrier conversion electric angle cosine value add Shaft motor current Carrier conversion electric angle sine value ,get Shaft motor current ; Shaft motor current Carrier conversion electric angle cosine value reduce Shaft motor current Carrier conversion electric angle sine value ,get Shaft motor current .

[0012] In conjunction with the first aspect, in some embodiments, in the modulation wave generation step, the following steps are performed: Methods for converting shaft reference voltage to three-phase reference voltage include: Will Shaft reference voltage Carrier conversion electric angle cosine value reduce Shaft reference voltage Carrier conversion electric angle sine value ,get Shaft reference voltage ; Will Shaft reference voltage Carrier conversion electric angle sine value add Shaft reference voltage Carrier conversion electric angle cosine value ,get Shaft reference voltage ; Phase reference voltage equal Shaft reference voltage ; Shaft reference voltage Multiply by the second set coefficient and subtract Shaft reference voltage Multiply by the first set coefficient to obtain Phase reference voltage ; Shaft reference voltage Multiply by the first set coefficient and add Shaft reference voltage Multiply by the second set coefficient and take the opposite number to get Phase reference voltage ; Generation voltage modulation ratio The methods include: Phase voltage amplitude Multiply by the third set coefficient and add the DC bus voltage take To obtain the first intermediate variable ; Phase voltage amplitude take Divide by the first intermediate variable To obtain the second intermediate variable ; Second intermediate variable Multiply by the fourth set coefficient to obtain the voltage modulation ratio ; Methods for generating three-phase voltage modulation waves include: Take the maximum and minimum values ​​of the three-phase reference voltage; Calculate the average of the maximum and minimum values ​​to obtain the average reference voltage; Subtracting the average reference voltage from the phase reference voltage yields the result. Phase modulation reference voltage, ; Phase modulation reference voltage multiplied by the fifth setting coefficient divided by the phase voltage amplitude Multiply by the voltage modulation ratio ,get Phase voltage modulated wave.

[0013] In conjunction with the first aspect, in some embodiments, the method for generating the drive signal for the power switching device in the air conditioner compressor motor drive circuit during the pulse width modulation step includes: Compare Phase voltage modulation wave and triangular carrier Size; exist Phase voltage modulation wave is greater than or equal to triangular carrier wave At that time, the motor drive circuit is obtained. The drive signal of the first power switch in the phase bridge arm is high; by inverting the drive signal of the first power switch, the motor drive circuit is obtained. The drive signal for the fourth power switch in the phase bridge arm is low; Phase voltage modulation wave Less than triangular carrier At that time, the motor drive circuit is obtained. The drive signal of the first power switch in the phase bridge arm is low; by inverting the drive signal of the first power switch, the motor drive circuit is obtained. The drive signal for the fourth power switch in the phase bridge arm is high level; Take triangular carrier The opposite number of the carrier wave is obtained. ,Compare Phase voltage modulation wave and carrier Size; exist Phase voltage modulated wave is greater than or equal to carrier wave At that time, the motor drive circuit is obtained. The drive signal for the second power switch in the phase bridge arm is high; inverting the drive signal for the second power switch yields the motor drive circuit. The drive signal for the third power switch in the phase bridge arm is low; Phase voltage modulation wave is smaller than carrier wave At that time, the motor drive circuit is obtained. The drive signal for the second power switch in the phase bridge arm is low; inverting the drive signal for the second power switch yields the motor drive circuit. The drive signal for the third power switch in the phase bridge arm is high level.

[0014] In conjunction with the first aspect, in some embodiments, the method further includes a rotor position calculation step: Shaft reference voltage reduce Shaft motor current and motor phase resistance The product of , we get Back electromotive force of shaft motor stator ;right Back electromotive force of shaft motor stator Integrating to obtain stator flux linkage of shaft motor ; stator flux linkage of shaft motor reduce Shaft motor current and Shaft motor inductance The product of , we get Effective magnetic flux linkage of shaft motor rotor ; Shaft reference voltage reduce Shaft motor current and motor phase resistance The product of , we get Back electromotive force of shaft motor stator ;right Back electromotive force of shaft motor stator Integrating to obtain stator flux linkage of shaft motor ; stator flux linkage of shaft motor reduce Shaft motor current and Shaft motor inductance The product of , we get Effective magnetic flux linkage of shaft motor rotor ; Will Effective magnetic flux linkage of shaft motor rotor and Effective magnetic flux linkage of shaft motor rotor The position of the motor rotor is obtained by performing arctangent function calculation. ; Regarding the rotor position angle of the motor The electric angular velocity of the motor is obtained by differentiation. Electric angular velocity of the motor Divide by the number of motor pole pairs Obtain the actual angular velocity of the motor ; Determine the position of the motor rotor Is it greater than If so, obtain the intermediate angle. For the position of the motor rotor reduce If not, obtain the intermediate angle. For the position of the motor rotor Determine the median angle If the value is less than 0, obtain the electrical angle of the motor rotor position. For the middle angle add If not, obtain the electrical angle of the motor rotor position. For the middle angle .

[0015] In conjunction with the first aspect, in some embodiments, during the speed control step, the following is obtained: Shaft current command The methods include: Calculate the reference command for the set speed. With the actual angular velocity of the motor The difference is used to obtain the speed error. ; Speed ​​error proportional coefficient of speed controller Obtain the proportional term of the speed controller ; Speed ​​error integral coefficient of speed controller Then, the integral term of the speed controller is obtained by first integrating and then limiting the amplitude. Trigger signal at the switching moment When it is high, its rising edge causes the integral term of the speed controller to be obtained by integral limiting. The third integrator is reset, and the integration term is... Reset to Shaft initial reference current ; Proportional term of speed controller Integral term of speed controller After being limited, it was obtained Shaft current command ; get Shaft reference current The methods include: trigger signals at the switching time. Before the high level, Shaft reference current To set up virtual Shaft starting current Trigger signal at the switching moment When it is high level, Shaft reference current for Shaft current command .

[0016] In conjunction with the first aspect, in some embodiments, during the current control step, the following is obtained: Shaft reference current The methods include: Trigger signal at the switching moment Before the high level, Shaft reference current =0; Trigger signal at the switching moment When the level is high, the fourth integrator is reset, causing the output of the fourth integrator to... for Shaft initial reference current ; exist Shaft initial reference current Based on the instantaneous switching of integral limiting through the fourth integrator Axis current descent slope The value after that is obtained. Shaft reference current ; get Shaft reference voltage The methods include: calculate Shaft reference current and Shaft motor current The difference is obtained. Shaft current error ; Shaft current error take The proportional gain of the shaft current controller get The proportional term of the shaft current controller ; Shaft current error take Integral coefficient of shaft current controller Then, integration followed by amplitude limiting is performed to obtain... Integral term of shaft current controller Trigger signal at the switching moment When it is high, its rising edge enables integration and limiting to obtain... Integral term of shaft current controller The fifth integrator is reset, and the integration term is... Reset to Shaft initial reference voltage ; The proportional term of the shaft current controller add Integral term of shaft current controller After being limited, it was obtained Shaft reference voltage ; get Shaft reference voltage The methods include: calculate Shaft reference current and Shaft motor current The difference is obtained. Shaft current error ; Shaft current error take The proportional gain of the shaft current controller get The proportional term of the shaft current controller ; Shaft current error take Integral coefficient of shaft current controller Then, integration followed by amplitude limiting is performed to obtain... Integral term of shaft current controller Trigger signal at the switching moment When it is high, its rising edge enables integration and limiting to obtain... Integral term of shaft current controller The sixth integrator is reset, and the integration term is... Reset to Shaft initial reference voltage ; The proportional term of the shaft current controller add Integral term of shaft current controller After being limited, it was obtained Shaft reference voltage .

[0017] In a second aspect, the present invention provides a coordinate transformation-based air conditioning compressor speed smooth switching control system for implementing the coordinate transformation-based air conditioning compressor speed smooth switching control method described in the first aspect of the present invention, comprising: The zero-speed start-up angle generation module is configured to: be based on the mechanical speed reset signal. For the rate of change of speed during startup Integral limiting determines the mechanical speed at startup. Based on the mechanical speed at startup and setting the allowed switching speed of the mechanical parts The size of the signal determines the trigger signal for the switching moment. ;Mechanical speed at startup After proportional and integral limiting, the starting electrical angle is generated by taking the modulus. ; The rotor angle processing module is configured to: base its signal on the trigger signal at the switching moment. According to the electric angle at startup Electrical angle of motor rotor position Obtain the electrical angle of the coordinate transformation ; Electrical angle during startup Electrical angle with motor rotor position The difference is used to limit the angle range to obtain the angle error value. ; The current transformation module is configured to: transform electrical angles based on coordinate transformation. Convert the three-phase motor current into Shaft motor current; The coordinate transformation instantaneous switching module is configured to: be based on angle error values. and the trigger signal for switching time ,Will The shaft reference voltage is transformed into a rotating coordinate system corresponding to the actual rotor position of the motor at the switching moment. Shaft initial reference voltage and Shaft initial reference voltage And will set virtual Shaft starting current Convert to the rotating coordinate system corresponding to the actual rotor position of the motor at the switching moment. Shaft initial reference current and Shaft initial reference current ; The speed controller is configured to: trigger signal based on the switching time. Reference command for setting speed With the actual angular velocity of the motor Speed ​​error After scaling, integrating, and limiting, we obtain... Shaft current command ,according to Shaft current command and setting virtual Shaft starting current The size is obtained Shaft reference current ; Current controller I is configured to: trigger signal based on switching time. According to the instantaneous switch Axis current descent slope and Shaft initial reference current get Shaft reference current ,right Shaft reference current and Shaft motor current of Shaft current error After scaling, integrating, and limiting, we obtain... Shaft reference voltage ; Current controller II is configured to: trigger signal based on switching time. ,right Shaft reference current and Shaft motor current of Shaft current error After scaling, integrating, and limiting, we obtain... Shaft reference voltage ; The modulation wave generation module is configured to: generate electrical angles based on coordinate transformation. ,Will Convert the shaft reference voltage to a three-phase reference voltage; Shaft reference voltage square plus Shaft reference voltage The square of the phase voltage amplitude is obtained by taking the square root of the square of the phase voltage amplitude. Based on phase voltage amplitude and DC bus voltage Generation voltage modulation ratio Based on three-phase reference voltage and phase voltage amplitude and voltage modulation ratio Generate a three-phase voltage modulation wave; The pulse width modulation module is configured to generate drive signals for the power switching devices in the air conditioner compressor motor drive circuit based on the magnitude of the three-phase voltage modulation wave and the set triangular carrier wave. The rotor position calculation module is configured to: be based on Shaft motor current, Calculate the actual angular velocity of the motor using shaft reference voltage. Electrical angle of motor rotor position .

[0018] Compared with the prior art, the advantages and positive effects of the present invention are as follows: (1) The air conditioning compressor speed smooth switching control method and system based on coordinate transformation provided by the present invention achieves accurate construction of electrical angle based on speed integral limiting in the low-speed stage through the zero-speed start-up angle generation step. Relying on the instantaneous switching step of coordinate transformation, the virtual coordinate system is instantaneously mapped to the actual rotor rotation coordinate system of the motor by angle error constraint. Combined with the rotor angle processing step, the angle deviation is limited to avoid angle jump. At the same time, the speed control step quickly performs closed-loop speed control after switching, and corrects the deviation between the set speed and the actual angular velocity in real time. Even if the load fluctuates during the operation of the air conditioning compressor, the speed can be stabilized by PI limiting adjustment, effectively suppressing torque pulsation and current impact at the moment of switching, realizing a shock-free smooth transition from open-loop start-up to closed-loop operation, and ensuring the stable operation of the air conditioning compressor.

[0019] (2) The air conditioning compressor speed smooth switching control method and system based on coordinate transformation provided by the present invention, through the current control step, controls the air conditioning compressor speed smooth switching. The shaft current error is dynamically constrained by PI limiting closed-loop adjustment. The shaft current amplitude, combined with the closed-loop control of speed-torque by the speed controller, can adapt to a wide range of load variation conditions of the air conditioning compressor. At the same time, through multiple limiting and smoothing adjustment mechanisms such as angle error limiting, speed change rate integral limiting, and current drop slope constraint, the risk of angle deviation, current oscillation and loss of synchronization caused by sudden load torque changes and friction resistance disturbances during the switching process is reduced, which significantly improves the anti-interference ability of the control system against external disturbances and enhances the overall operational robustness.

[0020] (3) The coordinate transformation-based air conditioning compressor speed smooth switching control method and system provided by the present invention abandons the hardware dependence of high-bandwidth current sensors and high-speed computing chips on the traditional low-speed high-frequency signal injection method, and does not require the installation of high-precision rotor position sensors. It only realizes rotor position and speed estimation through stator current and voltage sampling and coordinate transformation algorithm. The algorithm logic is simple, the engineering implementation difficulty is low, and the hardware architecture is streamlined, which can effectively reduce the hardware cost of air conditioning compressor drive system. The control architecture is compatible with the general drive logic of permanent magnet synchronous motors. It is not only suitable for the PMSM drive control of air conditioning compressors, but can also be extended to industrial permanent magnet synchronous motor loads such as fans and water pumps. It is especially suitable for industrial and home appliance application scenarios with moderate low-speed dynamic performance requirements, low cost, and high reliability requirements. Its versatility and engineering adaptability are outstanding.

[0021] (4) The air conditioning compressor speed smooth switching control method and system based on coordinate transformation provided by the present invention adopts open-loop starting of electrical angle based on integral amplitude limiting in the low speed stage, avoiding the starting failure problem caused by unreasonable pressure-frequency ratio slope in traditional constant pressure-frequency ratio control; after reaching the set switching speed, it quickly switches to speed-current dual closed-loop control, realizing seamless connection between low speed starting and medium-high speed precise speed regulation, ensuring stable and reliable compressor zero-speed starting, and improving the control accuracy of speed and torque under medium-high speed conditions. The overall control performance is significantly better than the existing sensorless starting control scheme. Attached Figure Description

[0022] Figure 1 This is a topology diagram of the motor drive circuit of the air conditioner compressor according to an embodiment of the present invention; Figure 2 This is a flowchart of the air conditioner compressor speed smooth switching control method based on coordinate transformation according to an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the principle of zero-speed start-up angle generation in an embodiment of the present invention. Figure 4 This is a schematic diagram illustrating the rotor angle processing principle of an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the current transformation principle of an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the principle of instantaneous switching of coordinate transformations in an embodiment of the present invention. Figure 7 This is a schematic diagram of the speed control principle in an embodiment of the present invention; Figure 8 This invention is derived from an embodiment of the present invention. Schematic diagram of shaft reference voltage; Figure 9 This invention is derived from an embodiment of the present invention. Schematic diagram of shaft reference voltage; Figure 10A schematic diagram illustrating the principle of generating modulated waves in an embodiment of the present invention; Figure 11 A schematic diagram illustrating the generation of drive signals for power switching devices in the air conditioner compressor motor drive circuit according to an embodiment of the present invention; Figure 12 This is a schematic diagram illustrating the rotor position calculation principle in an embodiment of the present invention. Figure 13 This is a structural block diagram of the air conditioning compressor speed smooth switching control system based on coordinate transformation according to an embodiment of the present invention; Figure 14 This is a schematic diagram of the PMSM speed under the traditional switching strategy when the load is 0.3 Nm. Figure 15 The diagram shows the PMSM speed under the smooth switching control method and system described in this invention when the load is 0.3 Nm. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0024] Figure 1 The diagram shows the topology of the air conditioner compressor motor drive circuit. The output of the motor drive circuit is connected to a permanent magnet synchronous motor (PMSM). Wherein: This is the DC bus voltage, which is usually obtained by a rectifier circuit. For the sake of simplifying the analysis, it is given here directly as the DC power supply. It is a DC bus energy storage capacitor. , , , Motor drive circuit IGBT power switching devices in the phase bridge arm, Motor drive circuit The capacitance of the phase bridge arm, Motor drive circuit The power diodes of the phase bridge arm, Motor drive circuit Input inductance of the phase bridge arm. , , , Motor drive circuit IGBT power switching devices in the phase bridge arm, Motor drive circuit The capacitance of the phase bridge arm, Motor drive circuit The power diodes of the phase bridge arm, Motor drive circuit Input inductance of the phase bridge arm. , , , Motor drive circuit IGBT power switching devices in the phase bridge arm, Motor drive circuit The capacitance of the phase bridge arm, Motor drive circuit The power diodes of the phase bridge arm, Motor drive circuit Input inductance of the phase bridge arm.

[0025] Since the three phase bridge arms of the motor drive circuit are completely symmetrical, the connection method is explained using phase a as an example. See also... Figure 1 DC bus energy storage capacitor The positive terminal is connected to the positive terminal of the DC bus. Point, DC bus energy storage capacitor The negative terminal is connected to the negative terminal of the DC bus. At this point, the negative terminal of the DC bus is connected to the negative terminal of the DC power supply. Power switching devices. The collector of the power switching device is connected to the positive terminal of the DC bus. emitter and power switching devices collector connection, power switching device emitter and power switching devices The collector is connected to Point, power switching device emitter and power switching devices collector connection, power switching device The emitter of the capacitor is connected to the negative terminal of the DC bus; The upper end is connected to collector, capacitor The lower end is connected to emitter; input inductor The right side and Point connection, input inductor The left side of the power diode Cathode connection, power diode The anode is connected to the positive terminal of the DC power supply. Points and PMSM Connected. Phase bridge arm and The connection method of the phase bridge arm and The phase bridge arms are the same, so they will not be described again here.

[0026] For the aforementioned air conditioning compressor, this invention provides a method and system for smooth speed switching control of an air conditioning compressor based on coordinate transformation. In the low-speed stage, it accurately constructs the electrical angle based on speed integral limiting, relies on instantaneous switching via coordinate transformation, and uses angle error constraints to achieve instantaneous mapping from the virtual coordinate system to the actual rotor rotation coordinate system of the motor. Combined with limiting the range of angle deviation, it avoids angle jumps. Simultaneously, after switching, it quickly performs speed-current dual closed-loop control, effectively suppressing torque pulsation and current surges at the moment of switching, achieving a smooth, shock-free transition from open-loop start-up to closed-loop operation, and ensuring the stable operation of the air conditioning compressor.

[0027] The following describes in detail the above-mentioned air conditioning compressor speed smooth switching control method and system based on coordinate transformation of the present invention with reference to the accompanying drawings and embodiments.

[0028] See Figure 2 The first aspect of this invention provides a method for smooth switching control of air conditioning compressor speed based on coordinate transformation, comprising: S1, Zero-speed start-up angle generation steps: See Figure 3 Based on mechanical speed reset signal For the rate of change of speed during startup Integral limiting determines the mechanical speed at startup. Based on the mechanical speed at startup and setting the allowed switching speed of the mechanical parts The size of the signal determines the trigger signal for the switching moment. ;Mechanical speed at startup After proportional and integral limiting, the starting electrical angle is generated by taking the modulus. By using integral limiting of the rate of change of speed and PI limiting generated by electrical angle to form a dual constraint, it can resist the speed and angle deviation caused by load resistance fluctuations and friction disturbances during the start-up phase, avoid loss of synchronization during the start-up process, and effectively improve the reliability of low-speed start-up of the permanent magnet synchronous motor of the air conditioning compressor.

[0029] Specifically, in one embodiment of the present invention, see further... Figure 3 To obtain the mechanical speed at startup The methods include: If the mechanical speed reset signal When the level is high, it will affect the rate of change of speed during startup. First integrator with integral limiting Reset, and set the first integrator to... The output is reset to 0; After the reset is complete, the signal is passed through the first integrator. Rate of change of speed at start-up The mechanical speed at startup is obtained by integral limiting. .

[0030] In this embodiment of the invention, the mechanical speed is obtained by performing an integral limiting calculation on the speed change rate during the start-up phase. This can constrain the speed change rate, avoid speed integral divergence and sudden changes, solve the problem of current oscillation and torque impact caused by excessive speed rise during traditional constant voltage-frequency ratio open-loop start-up, and ensure the air conditioning compressor starts smoothly at zero speed.

[0031] Specifically, in one embodiment of the present invention, see further... Figure 3 Generate the trigger signal at the switching time. The methods include: Compare the mechanical speed at startup and setting the allowed switching speed of the mechanical parts Size; Mechanical speed at startup Greater than or equal to the set allowable mechanical speed for switching And when the delay time is set via the delay module, the trigger signal for switching times is... Set to 1; otherwise, the trigger signal for switching times. Set to 0.

[0032] In this embodiment of the invention, the relationship between the starting mechanical speed and the preset allowable switching mechanical speed is used as the trigger criterion. When the speed reaches the safe switching range, the switching signal can be output in real time, avoiding the defects of unstable low-speed closed-loop control caused by early switching, excessively long open-loop control time caused by late switching, and poor resistance to load disturbances, thus ensuring that the operating conditions are stable and controllable at the switching moment.

[0033] Specifically, in one embodiment of the present invention, see further... Figure 3 Generates the starting electric angle The methods include: Mechanical speed at startup The starting electric angular velocity is obtained by multiplying by a proportional coefficient. ; Electric angular velocity at startup Integral limiting yields the starting potential angle Based on electrical angle reset signal The electric angular velocity at startup Second integrator with integral limit Reset, adjust the starting potential angle Reset is to reset electrical angle Reset electrical angle Values ​​that change over time; The starting potential angle After investigation The starting electrical angle is obtained by taking the model. .

[0034] Specifically, in the electrical angle reset signal When the value is high (i.e., 1), the electrical angular velocity at startup is... Second integrator with integral limit Reset. Reset electrical angle. Three different values ​​are provided (which can be set according to actual needs) to reset at different times, thus, the potential angle at startup. It varies at different times.

[0035] In this embodiment of the invention, the mechanical speed is proportionally and integrally limited to smooth out the sudden changes in electrical angle caused by speed fluctuations. At the same time, the electrical angle is constrained within one electrical cycle through modulo operation, so as to achieve continuous and accurate construction of rotor electrical angle during the low-speed open-loop start-up stage. This solves the problems of large deviation and angle jump in traditional open-loop start-up angle estimation, provides a reliable angle reference for instantaneous switching of subsequent coordinate transformation, reduces the angle error during open-loop and closed-loop switching, and suppresses switching torque pulsation and overcurrent.

[0036] S2. Rotor angle processing steps: See [link / reference] Figure 4 Trigger signal based on switching time According to the electric angle at startup Electrical angle of motor rotor position Obtain the electrical angle of the coordinate transformation ; Electrical angle during startup Electrical angle with motor rotor position The difference is used to limit the angle range to obtain the angle error value. .

[0037] Specifically, in one embodiment of the present invention, see further... Figure 4 The coordinate transformation electrical angle is obtained. The methods include: coordinate transformation electrical angle during startup. Electrical angle at startup The trigger signal at the switching time When the value is 1, its rising edge will transform the coordinates by electrical angle. Updated to motor rotor position electrical angle .

[0038] In this embodiment of the invention, the coordinate transformation electrical angle is updated to the actual rotor position electrical angle of the motor in one step by triggering the rising edge of the switching moment signal. This achieves instantaneous synchronous switching from the open-loop virtual angle reference to the closed-loop actual rotor angle reference, eliminating angle update delay and avoiding coordinate transformation misalignment caused by lag in angle information. Before switching, the system operates stably based on the open-loop starting electrical angle. At the moment of switching, it directly aligns with the actual rotor position electrical angle, avoiding continuous deviation caused by gradual angle transition and effectively eliminating the problems caused by coordinate system mismatch and accumulated angle deviation. Sudden changes in shaft current and drastic fluctuations in torque ensure a smooth transition from open-loop start-up to closed-loop operation of the air conditioning compressor.

[0039] Specifically, in one embodiment of the present invention, see further... Figure 4 The angle error value is obtained. The methods include: Determine the electric angle at startup Electrical angle with motor rotor position The difference Is it greater than ; If the difference Greater than To obtain the intermediate value The difference minus If the difference Less than or equal to To obtain the intermediate value The difference ; Determine the median value Is it less than ; If the median value Less than The angle error value is obtained. The median value Plus If the median value Greater than or equal to The angle error value is obtained. The median value .

[0040] In this embodiment of the invention, by limiting the angle error range, the deviation between the electrical angle at startup and the actual electrical angle of the motor rotor position is constrained within a reasonable range. This prevents the excessive angle difference at the switching moment from causing coordinate transformation distortion and sudden changes in controller output, effectively avoiding risks such as overcurrent and loss of synchronization, and improving the stability of the open-loop switching process.

[0041] S3. Current transformation steps: Based on coordinate transformation of electrical angles Convert the three-phase motor current into Shaft motor current.

[0042] Specifically, in one embodiment of the present invention, see [link to relevant documentation]. Figure 5 Convert the three-phase motor current into Methods for controlling shaft motor current include: Phase motor current take reduce Phase motor current take Subtract again Phase motor current take ,get Shaft motor current ; Phase motor current multiplied reduce Phase motor current multiplied ,get Shaft motor current ; Shaft motor current Carrier conversion electric angle cosine value add Shaft motor current Carrier conversion electric angle sine value ,get Shaft motor current ; Shaft motor current Carrier conversion electric angle cosine value reduce Shaft motor current Carrier conversion electric angle sine value ,get Shaft motor current .

[0043] In this embodiment of the invention, the electrical angle of the coordinate transformation at the start-up stage and the switching instant is used as the current transformation reference to realize the open-loop start-up stage and the closed-loop operation stage. Smooth connection of shaft motor current avoids three-phase interference caused by sudden changes in angle reference. The current conversion distortion of the shaft motor effectively reduces the risk of sudden current changes and overcurrent during the open-loop switching, ensuring the safety of the compressor drive system.

[0044] S4. Instantaneous switching steps for coordinate transformation: See Figure 6 Based on angle error value and the trigger signal for switching time ,Will The shaft reference voltage is transformed into a rotating coordinate system corresponding to the actual rotor position of the motor at the switching moment. Shaft initial reference voltage and Shaft initial reference voltage And will set virtual Shaft starting current Convert to the rotating coordinate system corresponding to the actual rotor position of the motor at the switching moment. Shaft initial reference current and Shaft initial reference current .

[0045] Specifically, the trigger signal at the switching moment Coordinate transformation is triggered on the rising edge, based on the angle error value. Calculate separately Shaft initial reference voltage and An initial reference current is established and latched. At the rising edge of the trigger signal during switching, coordinate transformations of the reference voltage and starting current are performed synchronously. Based on the angle error value, the control quantity is mapped from the open-loop virtual coordinate system to the actual rotor rotation coordinate system, achieving instantaneous matching between the control command and the actual rotor position. This eliminates the control coordinate system misalignment problem during the open-loop / closed-loop switching phase, preventing sudden torque changes at the source. By correcting the coordinate transformation of the shaft reference voltage and virtual starting current using the angle error value, the deviation between the virtual angle and the actual rotor angle at the switching moment can be accurately compensated, avoiding torque spikes caused by angle offsets. Sudden changes in shaft voltage and current commands significantly reduce current surges and torque pulsations during switching, enabling a smooth transition between air conditioning compressor speed and torque.

[0046] Specifically, in one embodiment of the present invention, see further... Figure 6 ,calculate Methods for initial shaft reference voltage include: Shaft reference voltage Multiplication angle error value cosine value add Shaft reference voltage Multiplication angle error value sine value ,get Shaft initial reference voltage ; Shaft reference voltage Multiplication angle error value cosine value reduce Shaft reference voltage Multiplication angle error value sine value ,get Shaft initial reference voltage .

[0047] In this embodiment of the invention, on the one hand, the cosine and sine components of the angle error are used to... The shaft reference voltage undergoes orthogonal rotational transformation, strictly adhering to the coordinate transformation law between two-phase rotating coordinate systems. This precisely compensates for the angular deviation between the virtual electrical angle and the actual rotor electrical angle at the switching moment, achieving accurate conversion from the virtual shaft reference voltage to the initial reference voltage in the closed-loop actual rotor coordinate system during the open-loop phase. This ensures that the voltage control command matches the actual rotor position. Furthermore, orthogonal sine and cosine operations are used to respectively... axis, Cross-compensation of the axis reference voltage fully preserves the amplitude and phase information of the original control command, avoiding voltage command coupling distortion caused by angle deviation, and fundamentally preventing issues caused by control coordinate system mismatch during switching. The sudden changes in shaft current, severe torque pulsation, and overcurrent phenomena are mitigated to achieve a smooth transition during the open-loop switching process of the air conditioning compressor.

[0048] Specifically, in one embodiment of the present invention, see further... Figure 6 ,calculate Methods for initial shaft reference current include: Set up virtual Shaft starting current Multiplication angle error value sine value ,get Shaft initial reference current ; Set up virtual Shaft starting current Multiplication angle error value cosine value ,get Shaft initial reference current .

[0049] In this embodiment of the invention, the starting current of the set virtual axis is rotated by the sine and cosine components of the angle error, and the starting current command in the virtual coordinate system of the open-loop stage is accurately mapped to the actual rotor rotation coordinate system of the motor. This makes the initial reference current of the closed loop match the actual rotor position, solves the problem of mismatch between the virtual current command and the actual control coordinate system at the switching moment, and provides an accurate initial current reference for closed-loop control.

[0050] S5, Speed ​​Control Procedure: See [link / reference] Figure 7 Trigger signal based on switching time Reference command for setting speed With the actual angular velocity of the motor Speed ​​error After scaling, integrating, and limiting, we obtain... Shaft current command ,according to Shaft current command and setting virtual Shaft starting current The size is obtained Shaft reference current .

[0051] Specifically, in one embodiment of the present invention, see further... Figure 7 ,get Shaft current command The methods include: Calculate the reference command for the set speed. With the actual angular velocity of the motor The difference is used to obtain the speed error. ; Speed ​​error proportional coefficient of speed controller Obtain the proportional term of the speed controller ; Speed ​​error integral coefficient of speed controller Then, the integral term of the speed controller is obtained by first integrating and then limiting the amplitude. Trigger signal at the switching moment When it is high (i.e., 1), its rising edge causes the integral term of the speed controller to be obtained by integral limiting. The third integrator Reset, and set the integral term. Reset to Shaft initial reference current ; Proportional term of speed controller Integral term of speed controller After being limited, it was obtained Shaft current command .

[0052] In this embodiment of the invention, on the one hand, the proportional term of the speed error quickly responds to the dynamic deviation of the speed, the integral term eliminates the steady-state speed error, and the output amplitude is limited and constrained. This allows for precise tracking of the set speed reference command, effectively suppressing speed drops and speed overshoot caused by load fluctuations during compressor operation, and improving the steady-state speed regulation performance of the motor. On the other hand, at the rising edge of the open-loop switching trigger signal, the third integrator of the speed controller is directly reset to the initial reference current of the shaft after the switch. This ensures that the initial state of the integral stage is completely matched with the closed-loop control requirements at the moment of switching, abandoning the traditional PI controller's method of integrating from zero. This eliminates the deviation of the initial integral value at the moment of switching from the root, preventing sudden changes in current and torque caused by the cumulative error of the integral in the early stage of the closed loop.

[0053] Specifically, in one embodiment of the present invention, the following is obtained: Shaft reference current The methods include: trigger signals at the switching time. Before it is high (i.e., 1), Shaft reference current To set up virtual Shaft starting current Trigger signal at the switching moment When it is high level, Shaft reference current for Shaft current command .

[0054] In this embodiment of the invention, on the one hand, before the switching trigger signal is high, the virtual signal is directly set. The shaft starting current is used as the shaft reference current to ensure a constant output torque during the low-speed open-loop start-up phase. This effectively avoids the current oscillation and torque fluctuation problems caused by unreasonable voltage-frequency ratio parameters in traditional constant voltage-frequency ratio control, ensuring smooth start-up of the air conditioning compressor from zero speed to low speed and reducing the risk of start-up failure. On the other hand, when the trigger signal becomes high, The shaft reference current is smoothly switched from a fixed virtual starting current to the closed-loop output of the speed controller. The shaft current command enables a seamless transition from open-loop constant torque starting control to speed-current dual closed-loop precise speed control, avoiding torque surges and current jumps caused by sudden changes in control commands. Furthermore, in the low-speed phase, a constant virtual starting current ensures sufficient starting torque, adapting to the high frictional resistance conditions during compressor startup. After switching, the shaft reference current is dynamically adjusted by the speed closed-loop to accurately track the set speed command, compensating for speed deviations caused by load fluctuations in real time, thus balancing starting reliability and steady-state speed regulation performance.

[0055] S6. Current control steps: See [link / reference] Figure 8 Trigger signal based on switching time According to the instantaneous switch Axis current descent slope and Shaft initial reference current get Shaft reference current ; for reference current and Shaft motor current The difference is processed by scaling, integrating, and limiting to obtain... Shaft reference voltage See also Figure 9 Trigger signal based on switching time ,right Shaft reference current and Shaft motor current The difference is processed by scaling, integrating, and limiting to obtain... Shaft reference voltage .

[0056] Specifically, in one embodiment of the present invention, see further... Figure 8 ,get Shaft reference current The methods include: Trigger signal at the switching moment Before the high level, Shaft reference current =0; Trigger signal at the switching moment When it is high, its rising edge will activate the fourth integrator. Reset the fourth integrator. Output for Shaft initial reference current ; exist Shaft initial reference current Based on the superposition of the fourth integrator Instantaneous switching of integral limiting Axis current descent slope The value after that is obtained. Shaft reference current .

[0057] In this embodiment of the invention, before switching, Setting the shaft reference current to zero simplifies the open-loop control logic and reduces motor reactive power loss; at switching moments, the fourth integrator is reset to match its output. The initial reference current of the shaft is used to achieve precise alignment of the closed-loop initial current; then, the fourth integrator is used to... The slope of the shaft current decrease is integrated and limited to make... The shaft reference current transitions smoothly and gradually, effectively suppressing sudden current changes and torque shocks during switching. At the same time, it constrains the risk of integral saturation, balances starting reliability and switching smoothness, and improves the overall robustness and engineering practicality of the system.

[0058] Specifically, in one embodiment of the present invention, see further... Figure 8 ,get Shaft reference voltage The methods include: calculate Shaft reference current and Shaft motor current The difference is obtained. Shaft current error ; Shaft current error take The proportional gain of the shaft current controller get The proportional term of the shaft current controller ; Shaft current error take Integral coefficient of shaft current controller Then, integration followed by amplitude limiting is performed to obtain... Integral term of shaft current controller Trigger signal at the switching moment When it is high, its rising edge enables integration and limiting to obtain... Integral term of shaft current controller The fifth integrator Reset, and set the integral term. Reset to Shaft initial reference voltage ; The proportional term of the shaft current controller add Integral term of shaft current controller After being limited, it was obtained Shaft reference voltage .

[0059] In this embodiment of the invention, by Shaft reference current and actual The difference in shaft motor current is used to construct the current error. A proportional-integral-limiting structure is employed to achieve precise closed-loop current regulation. Simultaneously, the rising edge of the trigger signal at the switching moment resets the fifth integrator to [the specified value]. The initial reference voltage of the shaft ensures that the initial integral value of the current controller is precisely matched with the actual operating conditions at the switching moment, avoiding the problems of initial integral deviation and integral saturation. It effectively suppresses sudden changes in voltage command, current surges and torque pulsations at the moment of switching between open and closed loops, improves control stability and dynamic response performance, and ensures a smooth and reliable switching process for the air conditioning compressor.

[0060] Specifically, in one embodiment of the present invention, see further... Figure 9 ,get Shaft reference voltage The methods include: calculate Shaft reference current and Shaft motor current The difference is obtained. Shaft current error ; Shaft current error take The proportional gain of the shaft current controller get The proportional term of the shaft current controller ; Shaft current error take Integral coefficient of shaft current controller Then, integration followed by amplitude limiting is performed to obtain... Integral term of shaft current controller Trigger signal at the switching moment When it is high, its rising edge enables integration and limiting to obtain... Integral term of shaft current controller The sixth integrator Reset, and set the integral term. Reset to Shaft initial reference voltage ; The proportional term of the shaft current controller add Integral term of shaft current controller After being limited, it was obtained Shaft reference voltage .

[0061] In this embodiment of the invention, based on Shaft reference current and actual The current error of the shaft motor current is controlled using a proportional-integral-limiting structure. The shaft current is precisely adjusted in a closed loop, and the sixth integrator is reset at the rising edge of the trigger signal at the switching moment. The initial reference voltage of the shaft ensures that the initial state of the current integral circuit is precisely matched with the operating conditions at the switching moment, avoiding initial integral deviation and integral saturation. It effectively suppresses voltage jumps, current surges and torque pulsations during the switching of open and closed loops, improves the dynamic stability of control, and ensures the smooth operation of the air conditioning compressor during the switching process.

[0062] S7. Modulation wave generation steps: See [link / reference] Figure 10 Based on coordinate transformation electrical angle ,Will Convert the shaft reference voltage to a three-phase reference voltage; Shaft reference voltage square plus Shaft reference voltage The square of the phase voltage amplitude is obtained by taking the square root of the square of the phase voltage amplitude. Based on phase voltage amplitude and DC bus voltage Generation voltage modulation ratio Based on three-phase reference voltage and phase voltage amplitude and voltage modulation ratio Generate a three-phase voltage modulation wave.

[0063] Specifically, in one embodiment of the present invention, see further... Figure 10 ,Will Methods for converting shaft reference voltage to three-phase reference voltage include: Will Shaft reference voltage Carrier conversion electric angle cosine value reduce Shaft reference voltage Carrier conversion electric angle sine value ,get Shaft reference voltage ; Will Shaft reference voltage Carrier conversion electric angle sine value add Shaft reference voltage Carrier conversion electric angle cosine value ,get Shaft reference voltage ; Phase reference voltage equal Shaft reference voltage ; Shaft reference voltage Multiply by the second set coefficient and subtract Shaft reference voltage Multiply by the first set coefficient to obtain Phase reference voltage ; Shaft reference voltage Multiply by the first set coefficient and add Shaft reference voltage Multiply by the second set coefficient and take the opposite number to get Phase reference voltage .

[0064] In this embodiment of the invention, the first setting coefficient is 0.5, and the second setting coefficient is 0.866. It should be noted that the first and second setting coefficients can be set according to actual needs.

[0065] In this embodiment of the invention, the transformation is based on electrical angle and achieved through orthogonal sine and cosine operations. The precise conversion of the shaft reference voltage to the two-phase stationary coordinate system voltage, combined with fixed coefficient calculations, completes the decoupling mapping from two-phase to three-phase reference voltage. It strictly matches the voltage vector transformation law of the permanent magnet synchronous motor, ensuring that the three-phase reference voltage and the motor rotor position are synchronized in real time. It effectively suppresses three-phase voltage distortion and harmonic disturbances during open-loop and closed-loop switching, improves voltage output continuity and modulation stability, and ensures the control accuracy and smooth operation of the air conditioning compressor drive system.

[0066] Specifically, in one embodiment of the present invention, see further... Figure 10 Generate voltage modulation ratio The methods include: Phase voltage amplitude Multiply by the third set coefficient and add the DC bus voltage take To obtain the first intermediate variable ; Phase voltage amplitude take Divide by the first intermediate variable To obtain the second intermediate variable ; Second intermediate variable Multiply by the fourth set coefficient to obtain the voltage modulation ratio .

[0067] In this embodiment of the invention, the third setting coefficient is 2.5981, and the fourth setting coefficient is 0.866. It should be noted that the third and fourth setting coefficients can be set according to actual needs.

[0068] In this embodiment, the voltage modulation ratio is obtained by step-by-step calculation of the phase voltage amplitude and DC bus voltage combined with the corresponding set coefficients. This can dynamically adapt to bus voltage fluctuations, accurately constrain the output voltage amplitude, avoid over-modulation and voltage saturation problems, optimize the output quality of the three-phase modulation wave, ensure stable driving of power switching devices, and improve the control reliability and voltage utilization of the air conditioning compressor drive system.

[0069] Specifically, in one embodiment of the present invention, see further... Figure 10 Methods for generating three-phase voltage modulation waves include: Take the maximum value of the three-phase reference voltage. and minimum value ; Calculate the maximum value and minimum value The average value is used to obtain the average reference voltage. ; Phase reference voltage Reduced average reference voltage ,get Phase modulation reference voltage , ; Phase modulation reference voltage Multiply by the fifth set coefficient and divide by the phase voltage amplitude Multiply by the voltage modulation ratio ,get Phase voltage modulation wave .

[0070] In this embodiment of the invention, the fifth setting coefficient is set to 1.1547. It should be noted that the fifth setting coefficient can be set according to actual needs.

[0071] In this embodiment of the invention, the average reference voltage is obtained by extracting the maximum and minimum values ​​of the three-phase reference voltage, and the neutral point offset processing is performed on each phase reference voltage to obtain the phase modulation reference voltage. Then, a three-phase voltage modulation wave is generated by combining the set coefficient, phase voltage amplitude and voltage modulation ratio. This can effectively suppress common-mode voltage, improve the utilization rate of DC bus voltage, optimize the quality of modulation waveform, reduce the loss of switching devices, ensure the smooth driving process of air conditioning compressor motor, and further enhance the operational stability during open-loop switching.

[0072] Specifically, see [link to relevant documentation] Figure 10 ,generate Methods for phase voltage modulation waves include: Take the maximum value of the three-phase reference voltage. and minimum value ; Calculate the maximum value and minimum value The average value is used to obtain the average reference voltage. ; Phase reference voltage Reduced average reference voltage ,get Phase modulation reference voltage ; Phase modulation reference voltage Multiply by the fifth set coefficient and divide by the phase voltage amplitude Multiply by the voltage modulation ratio ,get Phase voltage modulation wave .

[0073] Specifically, see [link to relevant documentation] Figure 10 ,generate Methods for phase voltage modulation waves include: Take the maximum value of the three-phase reference voltage. and minimum value ; Calculate the maximum value and minimum value The average value is used to obtain the average reference voltage. ; Phase reference voltage Reduced average reference voltage ,get Phase modulation reference voltage ; Phase modulation reference voltage Multiply by the fifth set coefficient and divide by the phase voltage amplitude Multiply by the voltage modulation ratio ,get Phase voltage modulation wave .

[0074] Specifically, see [link to relevant documentation] Figure 10 ,generate Methods for phase voltage modulation waves include: Take the maximum value of the three-phase reference voltage. and minimum value ; Calculate the maximum value and minimum value The average value is used to obtain the average reference voltage. ; Phase reference voltage Reduced average reference voltage ,get Phase modulation reference voltage ; Phase modulation reference voltage Multiply by the fifth set coefficient and divide by the phase voltage amplitude Multiply by the voltage modulation ratio ,get Phase voltage modulation wave .

[0075] S8. Pulse Width Modulation Step: Based on the magnitude of the three-phase voltage modulation wave and the set triangular carrier wave, generate the drive signal for the power switching device in the air conditioner compressor motor drive circuit.

[0076] Specifically, in one embodiment of the present invention, the method for generating drive signals for power switching devices in the air conditioner compressor motor drive circuit includes: Compare Phase voltage modulation wave With triangular carrier Size; exist Phase voltage modulation wave Greater than or equal to triangular carrier At that time, the motor drive circuit is obtained. Drive signal of the first power switching device in the phase bridge arm High level; the drive signal for the first power switching device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the fourth power switching device in the phase bridge arm Low level; Phase voltage modulation wave Less than triangular carrier At that time, the motor drive circuit is obtained. Drive signal of the first power switching device in the phase bridge arm Low level; drive signal for the first power switching device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the fourth power switching device in the phase bridge arm High level; Take triangular carrier The opposite number of the carrier wave is obtained. ,Compare Phase voltage modulation wave With carrier Size; exist Phase voltage modulation wave Greater than or equal to carrier At that time, the motor drive circuit is obtained. Drive signal of the second power switching device in the phase bridge arm High level; the drive signal for the second power switching device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the third power switching device in the phase bridge arm Low level; Phase voltage modulation wave Less than carrier At that time, the motor drive circuit is obtained. Drive signal of the second power switching device in the phase bridge arm Low level; drive signal for the second power switch device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the third power switching device in the phase bridge arm It is a high level.

[0077] In this embodiment, by comparing the phase voltage modulation wave with a triangular carrier wave and an inverse triangular carrier wave respectively, complementary power switching device drive signals for the upper and lower bridge arms are generated. This strictly ensures that the drive signals of the upper and lower switching transistors on the same bridge arm are mutually exclusive, effectively avoiding the risk of bridge arm shoot-through short circuit. At the same time, the dual-carrier comparison method is used to accurately output the drive logic of each phase bridge arm, making the switching timing of the switching devices precise and controllable, and the modulation output smooth and stable. This can effectively suppress current surges and torque ripples during the open-loop switching process, and improve the operational safety, stability and switching control reliability of the air conditioning compressor drive circuit.

[0078] Specifically, see [link to relevant documentation] Figure 11 Generate compressor motor drive circuit The driving signal methods for power switching devices in the phase bridge arm include: Compare Phase voltage modulation wave With triangular carrier Size; exist Phase voltage modulation wave Greater than or equal to triangular carrier At that time, the motor drive circuit is obtained. Drive signal of the first power switching device in the phase bridge arm High level; the drive signal for the first power switching device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the fourth power switching device in the phase bridge arm Low level; Phase voltage modulation wave Less than triangular carrier At that time, the motor drive circuit is obtained. Drive signal of the first power switching device in the phase bridge arm Low level; drive signal for the first power switching device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the fourth power switching device in the phase bridge arm High level; Take triangular carrier The opposite number of the carrier wave is obtained. ,Compare Phase voltage modulation wave With carrier Size; exist Phase voltage modulation wave Greater than or equal to carrier At that time, the motor drive circuit is obtained. Drive signal of the second power switching device in the phase bridge arm High level; the drive signal for the second power switching device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the third power switching device in the phase bridge arm Low level; Phase voltage modulation wave Less than carrier At that time, the motor drive circuit is obtained. Drive signal of the second power switching device in the phase bridge arm Low level; drive signal for the second power switch device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the third power switching device in the phase bridge arm It is a high level.

[0079] Specifically, see [link to relevant documentation] Figure 11 Generate compressor motor drive circuit The driving signal methods for power switching devices in the phase bridge arm include: Compare Phase voltage modulation wave With triangular carrier Size; exist Phase voltage modulation wave Greater than or equal to triangular carrier At that time, the motor drive circuit is obtained. Drive signal of the first power switching device in the phase bridge arm High level; the drive signal for the first power switching device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the fourth power switching device in the phase bridge arm Low level; Phase voltage modulation wave Less than triangular carrier At that time, the motor drive circuit is obtained. Drive signal of the first power switching device in the phase bridge arm Low level; drive signal for the first power switching device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the fourth power switching device in the phase bridge arm High level; Take triangular carrier The opposite number of the carrier wave is obtained. ,Compare Phase voltage modulation wave With carrier Size; exist Phase voltage modulation wave Greater than or equal to carrier At that time, the motor drive circuit is obtained. Drive signal of the second power switching device in the phase bridge arm High level; the drive signal for the second power switching device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the third power switching device in the phase bridge arm Low level; Phase voltage modulation wave Less than carrier At that time, the motor drive circuit is obtained. Drive signal of the second power switching device in the phase bridge arm Low level; drive signal for the second power switch device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the third power switching device in the phase bridge arm It is a high level.

[0080] Specifically, see [link to relevant documentation] Figure 11 Generate compressor motor drive circuit The driving signal methods for power switching devices in the phase bridge arm include: Compare Phase voltage modulation wave With triangular carrier Size; exist Phase voltage modulation wave Greater than or equal to triangular carrier At that time, the motor drive circuit is obtained. Drive signal of the first power switching device in the phase bridge arm High level; the drive signal for the first power switching device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the fourth power switching device in the phase bridge arm Low level; Phase voltage modulation wave Less than triangular carrier At that time, the motor drive circuit is obtained. Drive signal of the first power switching device in the phase bridge arm Low level; drive signal for the first power switching device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the fourth power switching device in the phase bridge arm High level; Take triangular carrier The opposite number of the carrier wave is obtained. ,Compare Phase voltage modulation wave With carrier Size; exist Phase voltage modulation wave Greater than or equal to carrier At that time, the motor drive circuit is obtained. Drive signal of the second power switching device in the phase bridge arm High level; the drive signal for the second power switching device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the third power switching device in the phase bridge arm Low level; Phase voltage modulation wave Less than carrier At that time, the motor drive circuit is obtained. Drive signal of the second power switching device in the phase bridge arm Low level; drive signal for the second power switch device. Invert the values ​​to obtain the motor drive circuit. Drive signal of the third power switching device in the phase bridge arm It is a high level.

[0081] In one embodiment of the present invention, the method further includes a rotor position calculation step. See also Figure 12 The rotor position calculation step includes: Shaft reference voltage reduce Shaft motor current and motor phase resistance The product of , we get Back electromotive force of shaft motor stator ;right Back electromotive force of shaft motor stator Integrating to obtain stator flux linkage of shaft motor ; stator flux linkage of shaft motor reduce Shaft motor current and Shaft motor inductance The product of , we get Effective magnetic flux linkage of shaft motor rotor ; Shaft reference voltage reduce Shaft motor current and motor phase resistance The product of , we get Back electromotive force of shaft motor stator ;right Back electromotive force of shaft motor stator Integrating to obtain stator flux linkage of shaft motor ; stator flux linkage of shaft motor reduce Shaft motor current and Shaft motor inductance The product of , we get Effective magnetic flux linkage of shaft motor rotor ; Will Effective magnetic flux linkage of shaft motor rotor and Effective magnetic flux linkage of shaft motor rotor The position of the motor rotor is obtained by performing arctangent function calculation. ; Regarding the rotor position angle of the motor The electric angular velocity of the motor is obtained by differentiation. Electric angular velocity of the motor Divide by the number of motor pole pairs Obtain the actual angular velocity of the motor ; Determine the position of the motor rotor Is it greater than If so, obtain the intermediate angle. For the position of the motor rotor reduce If not, obtain the intermediate angle. For the position of the motor rotor Determine the median angle If the value is less than 0, obtain the electrical angle of the motor rotor position. For the middle angle add If not, obtain the electrical angle of the motor rotor position. For the middle angle .

[0082] In this embodiment of the invention, the stator back electromotive force, stator flux linkage, and rotor effective flux linkage are calculated step by step using voltage, current, resistance, and inductance parameters. Then, the rotor position is calculated using arctangent calculation. The actual angular velocity of the motor is obtained through angle differentiation and pole pair conversion. The rotor position angle is normalized by interval correction, enabling accurate acquisition of rotor position and speed information without sensors. This eliminates the need for mechanical position sensors, reducing hardware costs and failure risks. At the same time, angle correction avoids angle jumps and phase misalignment problems, ensuring continuous and smooth rotor position signals. This provides accurate and reliable angle and speed feedback for open-loop switching, effectively improving the control accuracy and operational stability of the air conditioning compressor motor during low-speed start-up and switching.

[0083] A third aspect of this invention provides a coordinate transformation-based air conditioning compressor speed smooth switching control system, used to implement the coordinate transformation-based air conditioning compressor speed smooth switching control method described in the first aspect of this invention. See also... Figure 13 The control system includes: The zero-speed start-up angle generation module is configured to: be based on the mechanical speed reset signal. For the rate of change of speed during startup Integral limiting determines the mechanical speed at startup. Based on the mechanical speed at startup and setting the allowed switching speed of the mechanical parts The size of the signal determines the trigger signal for the switching moment. ;Mechanical speed at startup After proportional and integral limiting, the starting electrical angle is generated by taking the modulus. ; The rotor angle processing module is configured to: base its signal on the trigger signal at the switching moment. According to the electric angle at startup Electrical angle of motor rotor position Obtain the electrical angle of the coordinate transformation ; Electrical angle during startup Electrical angle with motor rotor position The difference is used to limit the angle range to obtain the angle error value. ; The current transformation module is configured to: transform electrical angles based on coordinate transformation. Convert the three-phase motor current into Shaft motor current; The coordinate transformation instantaneous switching module is configured to: be based on angle error values. and the trigger signal for switching time ,Will The shaft reference voltage is transformed into a rotating coordinate system corresponding to the actual rotor position of the motor at the switching moment. Shaft initial reference voltage and Shaft initial reference voltage And will set virtual Shaft starting current Convert to the rotating coordinate system corresponding to the actual rotor position of the motor at the switching moment. Shaft initial reference current and Shaft initial reference current ; The speed controller is configured to: trigger signal based on the switching time. Reference command for setting speed With the actual angular velocity of the motor Speed ​​error After scaling, integrating, and limiting, we obtain... Shaft current command ,according to Shaft current command and setting virtual Shaft starting current The size is obtained Shaft reference current ; Current controller I is configured to: trigger signal based on switching time. According to the instantaneous switch Axis current descent slope and Shaft initial reference current get Shaft reference current ,right Shaft reference current and Shaft motor current of Shaft current error After scaling, integrating, and limiting, we obtain... Shaft reference voltage ; Current controller II is configured to: trigger signal based on switching time. ,right Shaft reference current and Shaft motor current of Shaft current error After scaling, integrating, and limiting, we obtain... Shaft reference voltage ; The modulation wave generation module is configured to: generate electrical angles based on coordinate transformation. ,Will Convert the shaft reference voltage to a three-phase reference voltage; Shaft reference voltage square plus Shaft reference voltage The square of the phase voltage amplitude is obtained by taking the square root of the square of the phase voltage amplitude. Based on phase voltage amplitude and DC bus voltage Generation voltage modulation ratio Based on three-phase reference voltage and phase voltage amplitude and voltage modulation ratio Generate a three-phase voltage modulation wave; The pulse width modulation module is configured to generate drive signals for the power switching devices in the air conditioner compressor motor drive circuit based on the magnitude of the three-phase voltage modulation wave and the set triangular carrier wave. The rotor position calculation module is configured to: be based on Shaft motor current, Calculate the actual angular velocity of the motor using shaft reference voltage. Electrical angle of motor rotor position .

[0084] The control system described above in this invention achieves stable generation of speed and electrical angle during the low-speed open-loop phase and precise output of switching trigger signals through a zero-speed start-up angle generation module. The rotor angle processing module handles the controllable processing of electrical angle and angle error during coordinate transformation before and after switching. Combined with a current transformation module and a coordinate transformation instantaneous switching module, it achieves instantaneous and precise mapping of voltage and current control quantities between the virtual coordinate system and the actual rotor coordinate system. The speed controller and dual current controller respectively control the speed... The current closed-loop regulation and integrator reset at the switching moment ensure smooth connection of open-loop and closed-loop control commands and suppress switching shocks. The modulation wave generation module completes voltage coordinate transformation, modulation ratio calculation and three-phase modulation wave optimization generation. The pulse width modulation module outputs a safe and reliable switching drive signal. The rotor position calculation module accurately calculates rotor position and speed in a sensorless manner. The entire control system has clear logical layers and timing coordination matching, effectively solving problems such as torque pulsation, current shock and angle jump during open-loop and closed-loop switching in traditional solutions. It realizes zero-speed smooth start and smooth switching of the permanent magnet synchronous motor of the air conditioner compressor, improves the overall control accuracy, operation stability and anti-load disturbance capability of the system, and reduces hardware costs, making it easy to implement in low-cost embedded engineering.

[0085] To verify the effectiveness of the coordinate transformation-based air conditioner compressor speed smooth switching control method and control system described above, a simulation model was built in Matlab / Simulink. The DC power supply voltage was 200V, and the DC bus energy storage capacitor... 2000μF, three-phase input inductor , , Both are 5mH in size. , , All are 100μF. The parameters of the three-phase PMSM are as follows: motor phase resistance is 0.45Ω. The shaft inductance is 0.0025H. The shaft inductance is 0.00415H, the permanent magnet flux linkage of the PMSM is 0.142Wb, and the moment of inertia is 0.000296kg / m. 2 polar number The value is 3. The current frequency control based on coordinate transformation smoothly switches to speed closed-loop control, and a speed reference command is set. The initial value is set to 500 rpm, and the final value is set to 1000 rpm. This is the trigger signal for the switching time. The rising edge corresponds to a time of 3.5 seconds; virtual is set. Shaft starting current It is 7A. In the speed controller It is 0.05821. The value is 1.463. The upper limit of the third integrator and the output limit are both 42, and the lower limit is -2. After the instantaneous switch... Axis current descent slope The current is -7A / s, and the lower limit of the fourth integrator is 0. Current controller I... It is 0.628. The value is 113.096. The upper limit of the fifth integrator and the output limit are both 115.47, and the lower limit is -115.47. Current controller II's... It is 1.043. The value is 113.096. The upper limit of the sixth integrator and the output limit are both 115.47, and the lower limit is -115.47. In the zero-speed start-up angle generation module, the rate of change of speed during start-up is... The speed ramp signal is 500 rpm / s, the first integrator has a limit value of 500, and the allowed mechanical speed for switching is set. The rpm is 500, the delay time of the delay module is 0.5s, and the scaling factor is... 0.31416; Mechanical speed reset signal The signal is initially 1, then becomes 0 after 1 second; electrical angle reset signal. The signal is initially 1, then becomes 0 after 1 second; reset electrical angle. The signal is initially π, then 1.5π after 0.5s, and finally 0 after 1s; the limiting value of the second integrator is the theoretical floating-point numerical limit.

[0086] Figure 14 The value is the PMSM speed under the traditional switching strategy when the load is 0.3 Nm. Here, A represents the speed change caused by positioning, and B represents the speed change when switching from current frequency control to speed closed loop. When switching from current frequency control to speed closed loop control, the speed fluctuates greatly, dropping sharply from 500 rpm to 400 rpm, and will cause overshoot during the speed rise phase, making the speed control uneven. Figure 15 The PMSM speed under the smooth switching control method and system of this invention with a load of 0.3 Nm was measured. Here, C represents the smooth speed switching when switching from current frequency control to speed closed loop. Throughout the entire operation, the motor speed remained smooth without fluctuations. The maximum speed fluctuation during the switching process was 7 rpm. This demonstrates that the smooth switching control method and system of this invention do not cause large torque fluctuations in the motor during operation, thus avoiding impact on the system, ensuring a smooth switching process, and improving switching stability. These results prove the effectiveness of this invention.

[0087] The above embodiments are used to explain the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A method for smooth switching control of air conditioning compressor speed based on coordinate transformation, characterized in that, include: Zero-speed start-up angle generation steps: based on mechanical speed reset signal For the rate of change of speed during startup Integral limiting determines the mechanical speed at startup. Based on the mechanical speed at startup and setting the allowed switching speed of the mechanical parts The size of the signal determines the trigger signal for the switching moment. ;Mechanical speed at startup After proportional and integral limiting, the starting electrical angle is generated by taking the modulus. ; Rotor angle processing steps: based on the trigger signal at the switching moment According to the electric angle at startup Electrical angle of motor rotor position Obtain the electrical angle of the coordinate transformation ; Electrical angle during startup Electrical angle with motor rotor position The difference is used to limit the angle range to obtain the angle error value. ; Current transformation steps: Based on coordinate transformation of electrical angles Convert the three-phase motor current into Shaft motor current; Instantaneous switching steps for coordinate transformation: based on angle error value and the trigger signal for switching time ,Will The shaft reference voltage is transformed into a rotating coordinate system corresponding to the actual rotor position of the motor at the switching moment. Shaft initial reference voltage and Shaft initial reference voltage And will set virtual Shaft starting current Convert to the rotating coordinate system corresponding to the actual rotor position of the motor at the switching moment. Shaft initial reference current and Shaft initial reference current ; Speed ​​control steps: Based on the trigger signal at the switching time Reference command for setting speed With the actual angular velocity of the motor Speed ​​error After scaling, integrating, and limiting, we obtain... Shaft current command ,according to Shaft current command and setting virtual Shaft starting current The size is obtained Shaft reference current ; Current control steps: based on the trigger signal at the switching time According to the instantaneous switch Axis current descent slope and Shaft initial reference current get Shaft reference current ,right Shaft reference current and Shaft motor current of Shaft current error After scaling, integrating, and limiting, we obtain... Shaft reference voltage Trigger signal based on switching time ,right Shaft reference current and Shaft motor current of Shaft current error After scaling, integrating, and limiting, we obtain... Shaft reference voltage ; Modulated wave generation steps: Based on coordinate transformation electrical angle ,Will Convert the shaft reference voltage to a three-phase reference voltage; Shaft reference voltage square plus Shaft reference voltage The square of the phase voltage amplitude is obtained by taking the square root of the square of the phase voltage amplitude. Based on phase voltage amplitude and DC bus voltage Generation voltage modulation ratio ; Based on three-phase reference voltage and phase voltage amplitude and voltage modulation ratio Generate a three-phase voltage modulation wave; Pulse width modulation steps: Based on the magnitude of the three-phase voltage modulation wave and the set triangular carrier wave, the drive signal for the power switching device in the air conditioner compressor motor drive circuit is generated.

2. The air conditioning compressor speed smooth switching control method based on coordinate transformation as described in claim 1, characterized in that, In the zero-speed start-up angle generation step, the mechanical speed at start-up is obtained. The methods include: If the mechanical speed reset signal When the level is high, it will affect the rate of change of speed during startup. The first integrator of the integral limiting is reset, and the output of the first integrator is reset to 0. After the reset is completed, the rate of change of speed during startup is calculated using the first integrator. The mechanical speed at startup is obtained by integral limiting. ; Generate trigger signal at the switching moment The methods include: Compare the mechanical speed at startup and setting the allowed switching speed of the mechanical parts Size; Mechanical speed at startup Greater than or equal to the set allowable mechanical speed for switching And when the delay is set through the delay module, the trigger signal for the switching time is... Set to 1; otherwise, the trigger signal for switching times. Set to 0; Generating the starting electrical angle The methods include: Mechanical speed at startup Multiply by proportionality factor Obtain the electric angular velocity at startup ; Electric angular velocity at startup Integral limiting yields the starting potential angle Based on electrical angle reset signal The electric angular velocity at startup The second integrator of the integral limiting circuit is reset, and the starting potential angle is adjusted. Reset is to reset electrical angle Reset electrical angle Values ​​that change over time; The starting potential angle After investigation The starting electrical angle is obtained by taking the modulus. .

3. The air conditioning compressor speed smooth switching control method based on coordinate transformation as described in claim 1, characterized in that, In the rotor angle processing step, the coordinate transformation electrical angle is obtained. The methods include: coordinate transformation electrical angle during startup. Electrical angle at startup The trigger signal at the switching time When the value is 1, its rising edge will transform the coordinates by electrical angle. Updated to motor rotor position electrical angle ; Obtain the angle error value The methods include: Determine the electric angle at startup Electrical angle with motor rotor position The difference Is it greater than ; If the difference Greater than To obtain the intermediate value The difference minus If the difference Less than or equal to To obtain the intermediate value The difference ; Determine the median value Is it less than ; If the median value Less than The angle error value is obtained. The median value Plus If the median value Greater than or equal to The angle error value is obtained. The median value .

4. The air conditioning compressor speed smooth switching control method based on coordinate transformation as described in claim 1, characterized in that, In the current conversion step, the three-phase motor current is converted into... Methods for controlling shaft motor current include: Phase motor current take reduce Phase motor current take Subtract again Phase motor current take ,get Shaft motor current ; Phase motor current multiplied reduce Phase motor current multiplied ,get Shaft motor current ; Shaft motor current Carrier conversion electric angle cosine value add Shaft motor current Carrier conversion electric angle sine value ,get Shaft motor current ; Shaft motor current Carrier conversion electric angle cosine value reduce Shaft motor current Carrier conversion electric angle sine value ,get Shaft motor current .

5. The air conditioning compressor speed smooth switching control method based on coordinate transformation as described in claim 4, characterized in that, In the modulation wave generation step, Methods for converting shaft reference voltage to three-phase reference voltage include: Will Shaft reference voltage Carrier conversion electric angle cosine value reduce Shaft reference voltage Carrier conversion electric angle sine value ,get Shaft reference voltage ; Will Shaft reference voltage Carrier conversion electric angle sine value add Shaft reference voltage Carrier conversion electric angle cosine value ,get Shaft reference voltage ; Phase reference voltage equal Shaft reference voltage ; Shaft reference voltage Multiply by the second set coefficient and subtract Shaft reference voltage Multiply by the first set coefficient to obtain Phase reference voltage ; Shaft reference voltage Multiply by the first set coefficient and add Shaft reference voltage Multiply by the second set coefficient and take the opposite number to get Phase reference voltage ; Generation voltage modulation ratio The methods include: Phase voltage amplitude Multiply by the third set coefficient and add the DC bus voltage take To obtain the first intermediate variable ; Phase voltage amplitude take Divide by the first intermediate variable To obtain the second intermediate variable ; Second intermediate variable Multiply by the fourth set coefficient to obtain the voltage modulation ratio ; Methods for generating three-phase voltage modulation waves include: Take the maximum and minimum values ​​of the three-phase reference voltage; Calculate the average of the maximum and minimum values ​​to obtain the average reference voltage; Subtracting the average reference voltage from the phase reference voltage yields the result. Phase modulation reference voltage, ; Phase modulation reference voltage multiplied by the fifth setting coefficient divided by the phase voltage amplitude Multiply by the voltage modulation ratio ,get Phase voltage modulated wave.

6. The air conditioning compressor speed smooth switching control method based on coordinate transformation as described in claim 5, characterized in that, In the pulse width modulation step, the method for generating the drive signal for the power switching devices in the air conditioner compressor motor drive circuit includes: Compare Phase voltage modulation wave and triangular carrier Size; exist Phase voltage modulation wave is greater than or equal to triangular carrier wave At that time, the motor drive circuit is obtained. The drive signal of the first power switch in the phase bridge arm is high; inverting the drive signal of the first power switch yields the motor drive circuit. The drive signal for the fourth power switch in the phase bridge arm is low; Phase voltage modulation wave Less than triangular carrier At that time, the motor drive circuit is obtained. The drive signal of the first power switch in the phase bridge arm is low; by inverting the drive signal of the first power switch, the motor drive circuit is obtained. The drive signal for the fourth power switch in the phase bridge arm is high level; Take triangular carrier The opposite number of the carrier wave is obtained. ,Compare Phase voltage modulation wave and carrier Size; exist Phase voltage modulated wave is greater than or equal to carrier wave At that time, the motor drive circuit is obtained. The drive signal for the second power switch in the phase bridge arm is high; inverting the drive signal for the second power switch yields the motor drive circuit. The drive signal for the third power switch in the phase bridge arm is low; Phase voltage modulation wave is smaller than carrier wave At that time, the motor drive circuit is obtained. The drive signal for the second power switch in the phase bridge arm is low; inverting the drive signal for the second power switch yields the motor drive circuit. The drive signal for the third power switch in the phase bridge arm is high level.

7. The air conditioning compressor speed smooth switching control method based on coordinate transformation as described in claim 5, characterized in that, The method also includes a rotor position calculation step: Shaft reference voltage reduce Shaft motor current and motor phase resistance The product of , we get Back electromotive force of shaft motor stator ;right Back electromotive force of shaft motor stator Integrating to obtain stator flux linkage of shaft motor ; stator flux linkage of shaft motor reduce Shaft motor current and Shaft motor inductance The product of , we get Effective magnetic flux linkage of shaft motor rotor ; Shaft reference voltage reduce Shaft motor current and motor phase resistance The product of , we get Back electromotive force of shaft motor stator ;right Back electromotive force of shaft motor stator Integrating to obtain stator flux linkage of shaft motor ; stator flux linkage of shaft motor reduce Shaft motor current and Shaft motor inductance The product of , we get Effective magnetic flux linkage of shaft motor rotor ; Will Effective magnetic flux linkage of shaft motor rotor and Effective magnetic flux linkage of shaft motor rotor The position of the motor rotor is obtained by performing arctangent function calculation. ; Regarding the rotor position angle of the motor The electric angular velocity of the motor is obtained by differentiation. Electric angular velocity of the motor Divide by the number of motor pole pairs Obtain the actual angular velocity of the motor ; Determine the position of the motor rotor Is it greater than If so, obtain the intermediate angle. For the position of the motor rotor reduce If not, obtain the intermediate angle. For the position of the motor rotor Determine the median angle If the value is less than 0, obtain the electrical angle of the motor rotor position. For the middle angle add If not, obtain the electrical angle of the motor rotor position. For the middle angle .

8. The air conditioning compressor speed smooth switching control method based on coordinate transformation as described in claim 1, characterized in that, In the speed control step, the following is obtained: Shaft current command The methods include: Calculate the reference command for the set speed. With the actual angular velocity of the motor The difference is used to obtain the speed error. ; Speed ​​error proportional coefficient of speed controller Obtain the proportional term of the speed controller ; Speed ​​error integral coefficient of speed controller Then, the integral term of the speed controller is obtained by first integrating and then limiting the amplitude. Trigger signal at the switching moment When it is high, its rising edge causes the integral term of the speed controller to be obtained by integral limiting. The third integrator is reset, and the integration term is... Reset to Shaft initial reference current ; Proportional term of speed controller Add the integral term of the speed controller After being limited, it was obtained Shaft current command ; get Shaft reference current The methods include: trigger signals at the switching time. Before the high level, Shaft reference current To set up virtual Shaft starting current Trigger signal at the switching moment When it is high level, Shaft reference current for Shaft current command .

9. The air conditioning compressor speed smooth switching control method based on coordinate transformation as described in claim 1, characterized in that, In the current control step, we obtain Shaft reference current The methods include: Trigger signal at the switching moment Before the high level, Shaft reference current =0; Trigger signal at the switching moment When the signal is high, its rising edge resets the fourth integrator, causing the output of the fourth integrator to... for Shaft initial reference current ; exist Shaft initial reference current Based on the instantaneous switching of integral limiting through the fourth integrator Axis current descent slope The value after that is obtained. Shaft reference current ; get Shaft reference voltage The methods include: calculate Shaft reference current and Shaft motor current The difference is obtained. Shaft current error ; Shaft current error take The proportional gain of the shaft current controller get The proportional term of the shaft current controller ; Shaft current error take Integral coefficient of shaft current controller Then, integration followed by amplitude limiting is performed to obtain... Integral term of shaft current controller Trigger signal at the switching moment When it is high, its rising edge enables integration and limiting to obtain... Integral term of shaft current controller The fifth integrator is reset, and the integration term is... Reset to Shaft initial reference voltage ; The proportional term of the shaft current controller add Integral term of shaft current controller After being limited, it was obtained Shaft reference voltage ; get Shaft reference voltage The methods include: calculate Shaft reference current and Shaft motor current The difference is obtained. Shaft current error ; Shaft current error take The proportional gain of the shaft current controller get The proportional term of the shaft current controller ; Shaft current error take Integral coefficient of shaft current controller Then, integration followed by amplitude limiting is performed to obtain... Integral term of shaft current controller Trigger signal at the switching moment When it is high, its rising edge enables integration and limiting to obtain... Integral term of shaft current controller The sixth integrator is reset, and the integration term is... Reset to Shaft initial reference voltage ; The proportional term of the shaft current controller add Integral term of shaft current controller After being limited, it was obtained Shaft reference voltage .

10. A coordinate transformation-based air conditioning compressor speed smooth switching control system, used to implement the coordinate transformation-based air conditioning compressor speed smooth switching control method as described in any one of claims 1 to 9, characterized in that, include: The zero-speed start-up angle generation module is configured to: be based on the mechanical speed reset signal. For the rate of change of speed during startup Integral limiting determines the mechanical speed at startup. Based on the mechanical speed at startup and setting the allowed switching speed of the mechanical parts The size of the signal determines the trigger signal for the switching moment. ;Mechanical speed at startup After proportional and integral limiting, the starting electrical angle is generated by taking the modulus. ; The rotor angle processing module is configured to: base its signal on the trigger signal at the switching moment. According to the electric angle at startup Electrical angle of motor rotor position Obtain the electrical angle of the coordinate transformation ; Electrical angle during startup Electrical angle with motor rotor position The difference is used to limit the angle range to obtain the angle error value. ; The current transformation module is configured to: transform electrical angles based on coordinate transformation. Convert the three-phase motor current into Shaft motor current; The coordinate transformation instantaneous switching module is configured to: be based on angle error values. and the trigger signal for switching time ,Will The shaft reference voltage is transformed into a rotating coordinate system corresponding to the actual rotor position of the motor at the switching moment. Shaft initial reference voltage and Shaft initial reference voltage And will set virtual Shaft starting current Convert to the rotating coordinate system corresponding to the actual rotor position of the motor at the switching moment. Shaft initial reference current and Shaft initial reference current ; The speed controller is configured to: trigger signal based on the switching time. Reference command for setting speed With the actual angular velocity of the motor Speed ​​error After scaling, integrating, and limiting, we obtain... Shaft current command ,according to Shaft current command and setting virtual Shaft starting current The size is obtained Shaft reference current ; Current controller I is configured to: trigger signal based on switching time. According to the instantaneous switch Axis current descent slope and Shaft initial reference current get Shaft reference current ,right Shaft reference current and Shaft motor current of Shaft current error After scaling, integrating, and limiting, we obtain... Shaft reference voltage ; Current controller II is configured to: trigger signal based on switching time. ,right Shaft reference current and Shaft motor current of Shaft current error After scaling, integrating, and limiting, we obtain... Shaft reference voltage ; The modulation wave generation module is configured to: generate electrical angles based on coordinate transformation. ,Will Convert the shaft reference voltage to a three-phase reference voltage; Shaft reference voltage square plus Shaft reference voltage The square of the phase voltage amplitude is obtained by taking the square root of the square of the phase voltage amplitude. Based on phase voltage amplitude and DC bus voltage Generation voltage modulation ratio ; Based on three-phase reference voltage and phase voltage amplitude and voltage modulation ratio Generate a three-phase voltage modulation wave; The pulse width modulation module is configured to generate drive signals for the power switching devices in the air conditioner compressor motor drive circuit based on the magnitude of the three-phase voltage modulation wave and the set triangular carrier wave. The rotor position calculation module is configured to: be based on Shaft motor current, Calculate the actual angular velocity of the motor using shaft reference voltage. Electrical angle of motor rotor position .

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