An electromechanical converter regulation system for compressor drive

Abstract

This invention relates to the field of electric motor control technology and discloses an electromechanical converter regulation system for compressor drive, comprising: a bus current gradient acquisition unit for acquiring DC bus current gradient; a switching timing calculation unit for reconstructing the switching vector execution timing within the space voltage vector modulation period; and a pulse width signal generation unit for generating switching control signals. When the DC bus current gradient exceeds a preset load mutation threshold, the switching timing calculation unit subtracts the zero vector duration to obtain the adjustment compensation time and injects the adjustment compensation time into the effective vector according to the original ratio of the effective vector. This invention achieves quasi-synchronous offsetting between converter output power and mechanical load fluctuations, compensates for current hysteresis caused by load torque pulsation, suppresses electromagnetic noise, and improves the energy efficiency and robustness of the drive system.

Description

Technical Field

[0001] This invention belongs to the field of electric motor control technology, and particularly relates to an electromechanical converter regulation system for compressor drive. Background Technology

[0002] Currently, in compressor drive applications, electromechanical converters serve as energy conversion units, employing pulse width modulation (PWM) technology to control the motor's torque output and match the compressor's periodic load torque fluctuations. The industry typically uses a proportional-integral feedback-based current closed-loop regulation method, relying on collecting stator current and comparing it with the target command to determine the converter's pulse width output. Because the compressor generates significant load torque pulsations during rotation, the regulation system needs to adjust the power output in real time to maintain stable speed. For example, Chinese invention patent CN102829553B discloses a high-power single-phase heat pump water heater start-up control device. This device uses a soft-start drive module in conjunction with a high / low pressure rapid balancing device to reduce the starting current to 2-3 times the rated current, solving the problem of slow or unbalanced high / low pressure balancing during compressor standby. The technical problems of excessive starting current and lack of protection in the event of starting failure are addressed. However, in the pursuit of extreme energy efficiency, traditional feedback regulation methods suffer from physical sampling and calculation delays. The regulation action lags behind the actual physical evolution of load fluctuations, exhibiting a post-correction characteristic. This timing lag will cause phase shifts under high-speed operation or high-load conditions, resulting in asynchronous electromagnetic torque pulsation in the air gap magnetic field. The industry has tried to introduce pressure sensors to assist feedforward compensation, but due to the physical constraints of the refrigerant circulation environment, the reliability of the sensors in long-term operation is difficult to meet engineering requirements, and it increases the hardware material cost of the system. At the same time, the conventional duty cycle superposition regulation method is prone to changing the volt-second balance of the three-phase inverter bridge switching cycle, causing the composite trajectory of the space voltage vector to shift, generating high-frequency harmonic currents in the magnetic field.

[0003] Therefore, the technical problem to be solved by this invention is how to improve the converter's sensing rate of micro-load state without introducing external sensing components, and ensure that the adjustment command does not destroy the spatial trajectory purity of the stator magnetic field. Summary of the Invention

[0004] This invention provides an electromechanical converter regulation system for compressor drive, comprising:

[0005] The bus current gradient acquisition unit is used to acquire the DC bus current gradient, which characterizes the periodic load torque fluctuation characteristics of the compressor, by collecting the transient current signal of the sampling resistor on the DC bus side of the electromechanical converter.

[0006] The switching timing calculation unit is connected to the bus current gradient acquisition unit and is used to reconstruct the switching vector execution timing within the space voltage vector modulation period based on the DC bus current gradient.

[0007] The pulse width signal generation unit is used to generate control signals for the on / off states of power switches in the three-phase inverter bridge of the electromechanical converter based on the reconstructed switching vector execution timing. When the switching timing calculation unit determines that the DC bus current gradient exceeds the preset load mutation threshold, it initiates a redistribution operation for the zero vector idle period, specifically including: reducing the zero vector execution duration within the current space voltage vector modulation cycle to obtain the adjustment compensation duration; the switching timing calculation unit identifies the first original execution duration of the first effective vector and the second original execution duration of the second effective vector in the current sector, and according to the numerical ratio between the first original execution duration and the second original execution duration, it splits the adjustment compensation duration into a first duration increment and a second duration increment, injects the first duration increment into the first original execution duration, and injects the second duration increment into the second original execution duration to generate an updated vector execution sequence, and compensates for the stator current phase shift caused by the compressor load torque pulsation by increasing the synthetic amplitude of the space voltage vector under the physical constraint of maintaining the constant stator space flux electrical angle phase.

[0008] Preferably, the bus current gradient acquisition unit includes an oscillation interference suppression unit. The oscillation interference suppression unit is used to identify the attenuation envelope center point of the high-frequency ringing signal of the bus current generated by the operation of the power switch, and to trigger a sampling action within a preset time window after the attenuation envelope center point to obtain the DC bus current gradient.

[0009] Preferably, the switching timing calculation unit includes a low-speed state sensing unit. The low-speed state sensing unit is used to insert an unbalanced pulse vector into the space voltage vector modulation period when the compressor operating frequency is lower than a preset frequency threshold, and calculate the rotor position angle based on the response deviation of the DC bus current gradient to the unbalanced pulse vector. The pulse width signal generation unit corrects the phase of the switching control signal based on the rotor position angle.

[0010] Preferably, the switching timing calculation unit includes a residual analysis unit, which is used to monitor the range of the DC bus current gradient within multiple consecutive space voltage vector modulation cycles, and outputs a carrier frequency switching command for the pulse width signal generation unit when the range exceeds a preset rate of change threshold.

[0011] Preferably, when the switching timing calculation unit performs the duration increase operation of the first effective vector, the space voltage vector modulation period is set to be... The original execution time of the first valid vector in the current sector is The original execution time of the second effective vector is The execution time of the zero vector is If the compensation duration is adjusted to ΔT, then the execution time of the first effective vector after reconstruction is... Follow these rules: Where ΔT takes a value no greater than 90%.

[0012] Preferably, the switching timing calculation unit maintains the ratio of the increase in the first effective vector to the increase in the second effective vector consistent with the original duration ratio of the first effective vector to the second effective vector, thereby limiting the phase deviation between the reconstructed composite voltage vector and the unreconstructed composite voltage vector to no more than 0.05 rad.

[0013] Preferably, the system further includes a bus voltage monitoring unit for acquiring the DC bus voltage sag value; and a switching timing calculation unit for adjusting the gain coefficient of the compensation duration based on the DC bus voltage sag value.

[0014] Preferably, the switching timing calculation unit includes a limiting protection unit to block further increases in the adjustment compensation duration when the zero vector execution duration is compressed to 10μs, so as to maintain the volt-second balance within the space voltage vector modulation period.

[0015] Preferably, the system further includes a thermal drift calibration unit, which is used to obtain the real-time temperature of the sampling circuit in the bus current gradient acquisition unit, and output calibration coefficients to the switching timing calculation unit according to the preset temperature-resistance characteristic curve, so as to correct the quantization amplitude of the DC bus current gradient.

[0016] Preferably, the pulse width signal generation unit is connected to the hardware comparison register of the microcontroller, and the duty cycle of the PWM waveform is adjusted by rewriting the count value of the hardware comparison register at the update node of the space voltage vector modulation cycle, wherein the refresh frequency of the hardware comparison register is not less than 10kHz.

[0017] Compared with existing technologies, the electromechanical converter regulation system for compressor drives of the present invention has the following advantages:

[0018] 1. In the electromechanical converter regulation system, through the zero-vector time-domain deprivation and effective vector conformal expansion mechanism, the logic regulation unit achieves transient torque injection while maintaining a constant phase angle of the space voltage vector. By performing time-domain reorganization in the pulse width generation timer inside the microcontroller, the deducted zero-vector time slice is allocated according to the original time ratio of the two effective vectors in the current sector. Compared with the traditional scalar control method of directly superimposing duty cycles, this ensures that the spatial shape of the stator air gap magnetic field does not undergo eccentric distortion, eliminates high-frequency space harmonics caused by phase mismatch, and effectively reduces asynchronous harmonic currents and core eddy current losses in the stator winding. This allows the system to maintain the purity of the underlying electromagnetic energy conversion while resisting mechanical pulsation caused by the compressor crankshaft.

[0019] 2. Utilizing a two-phase gradient differential calibration mechanism, the feature extraction unit achieves self-alignment of sensing parameters by repeatedly using the effective vector rising phase and the zero vector falling phase within the pulse width modulation cycle. This scheme leverages the physical characteristic that the inductance values ​​of the same inductor cancel each other out during the charge and discharge cycle. By calculating the algebraic relationship between the rising and falling gradients, it extracts the pure load response component that excludes interference from the intrinsic inductance of the motor. This approach, which replaces the processing path of mathematical identification algorithms with physical feature offsetting, eliminates the impact of motor winding drift with operating temperature and stator current nonlinear saturation on load sensing accuracy. This ensures high operational stability of the system in a wide temperature range and under varying operating conditions, without requiring additional high-order matrix operation resources from the processor.

[0020] 3. A resonant energy valley sampling and locking mechanism is adopted. The sampling unit detects the voltage oscillation envelope generated by the switching edge of the power device to achieve dynamic decoupling of feature extraction phase and parasitic ringing noise. The system uses an internal capture unit to identify the center point of the attenuation envelope of the ringing signal and dynamically moves the sampling trigger signal to the energy stable region, thereby avoiding interference in the high-frequency non-steady-state region. This collaborative mechanism solves the sampling distortion problem caused by the extremely high switching frequency in the high-frequency converter, so that the acquisition of the current growth gradient is no longer limited by the fixed sampling delay, improves the signal-to-noise ratio of the control system under strong electromagnetic interference, and ensures the underlying reliability of the adjustment command. Attached Figure Description

[0021] Figure 1 This is a block diagram of the system control architecture and load mutation hedging logic of the present invention;

[0022] Figure 2 This is a flowchart of the bus current sensing timing and envelope sampling identification process of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0024] It should be noted that all directional and positional terms used in this invention, such as: up, down, left, right, front, back, vertical, horizontal, inner, outer, top, bottom, transverse, longitudinal, center, etc., are only used to explain the relative positional relationship and connection between components in a specific state (as shown in the accompanying drawings). They are only for the convenience of describing this invention and do not require that this invention be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention. In addition, the descriptions of "first," "second," etc., in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0025] In the description of this invention, unless otherwise explicitly specified and limited, the terms installation, connection, and linking should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0026] In the description of this specification, references to the terms "an embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example, and the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0027] An electromechanical converter regulation system for compressor drive, comprising:

[0028] The bus current gradient acquisition unit is used to acquire the DC bus current gradient, which characterizes the periodic load torque fluctuation characteristics of the compressor, by collecting the transient current signal of the sampling resistor on the DC bus side of the electromechanical converter.

[0029] The switching timing calculation unit is connected to the bus current gradient acquisition unit and is used to reconstruct the switching vector execution timing within the space voltage vector modulation period based on the DC bus current gradient.

[0030] The pulse width signal generation unit is used to generate control signals for the on / off states of power switches in the three-phase inverter bridge of the electromechanical converter based on the reconstructed switching vector execution timing. When the switching timing calculation unit determines that the DC bus current gradient exceeds the preset load mutation threshold, it initiates a redistribution operation for the zero vector idle period, specifically including: reducing the zero vector execution duration within the current space voltage vector modulation cycle to obtain the adjustment compensation duration; the switching timing calculation unit identifies the first original execution duration of the first effective vector and the second original execution duration of the second effective vector in the current sector, and according to the numerical ratio between the first original execution duration and the second original execution duration, it splits the adjustment compensation duration into a first duration increment and a second duration increment, injects the first duration increment into the first original execution duration, and injects the second duration increment into the second original execution duration to generate an updated vector execution sequence, and compensates for the stator current phase shift caused by the compressor load torque pulsation by increasing the synthetic amplitude of the space voltage vector under the physical constraint of maintaining the constant stator space flux electrical angle phase.

[0031] Preferably, the bus current gradient acquisition unit includes an oscillation interference suppression unit. The oscillation interference suppression unit is used to identify the attenuation envelope center point of the high-frequency ringing signal of the bus current generated by the operation of the power switch, and to trigger a sampling action within a preset time window after the attenuation envelope center point to obtain the DC bus current gradient.

[0032] Preferably, the switching timing calculation unit includes a low-speed state sensing unit. The low-speed state sensing unit is used to insert an unbalanced pulse vector into the space voltage vector modulation period when the compressor operating frequency is lower than a preset frequency threshold, and calculate the rotor position angle based on the response deviation of the DC bus current gradient to the unbalanced pulse vector. The pulse width signal generation unit corrects the phase of the switching control signal based on the rotor position angle.

[0033] Preferably, the switching timing calculation unit includes a residual analysis unit, which is used to monitor the range of the DC bus current gradient within multiple consecutive space voltage vector modulation cycles, and outputs a carrier frequency switching command for the pulse width signal generation unit when the range exceeds a preset rate of change threshold.

[0034] Preferably, when the switching timing calculation unit performs the duration increase operation of the first effective vector, the space voltage vector modulation period is set to be... The original execution time of the first valid vector in the current sector is The original execution time of the second effective vector is The execution time of the zero vector is If the compensation duration is adjusted to ΔT, then the execution time of the first effective vector after reconstruction is... Follow these rules: Where ΔT takes a value no greater than 90%.

[0035] Preferably, the switching timing calculation unit maintains the ratio of the increase in the first effective vector to the increase in the second effective vector consistent with the original duration ratio of the first effective vector to the second effective vector, thereby limiting the phase deviation between the reconstructed composite voltage vector and the unreconstructed composite voltage vector to no more than 0.05 rad.

[0036] Preferably, the system further includes a bus voltage monitoring unit for acquiring the DC bus voltage sag value; and a switching timing calculation unit for adjusting the gain coefficient of the compensation duration based on the DC bus voltage sag value.

[0037] Preferably, the switching timing calculation unit includes a limiting protection unit to block further increases in the adjustment compensation duration when the zero vector execution duration is compressed to 10μs, so as to maintain the volt-second balance within the space voltage vector modulation period.

[0038] Preferably, the system further includes a thermal drift calibration unit, which is used to obtain the real-time temperature of the sampling circuit in the bus current gradient acquisition unit, and output calibration coefficients to the switching timing calculation unit according to the preset temperature-resistance characteristic curve, so as to correct the quantization amplitude of the DC bus current gradient.

[0039] Preferably, the pulse width signal generation unit is connected to the hardware comparison register of the microcontroller, and the duty cycle of the PWM waveform is adjusted by rewriting the count value of the hardware comparison register at the update node of the space voltage vector modulation cycle, wherein the refresh frequency of the hardware comparison register is not less than 10kHz.

[0040] Example 1: In a single-rotor compressor drive scenario operating under ultra-low frequency, high load conditions, the output current loop of the electromechanical converter is subjected to periodic load torque pulsations caused by the eccentric rotation of the compressor crankshaft. The bus current gradient acquisition unit collects the transient current signal of the sampling resistor on the DC bus side of the electromechanical converter and outputs the DC bus current gradient characterizing the load torque fluctuation. The switching timing calculation unit receives the DC bus current gradient and compares it with a preset load mutation threshold. When the DC bus current gradient is greater than the load mutation threshold, the switching timing calculation unit reconstructs the space voltage vector modulation. The switching vector execution timing within the control cycle; the current change rate parameter extracted in this associated process directly characterizes the instantaneous evolution of the electromagnetic state. This parameter provides the switching timing calculation unit with a time reference synchronized with mechanical disturbances, enabling the duty cycle adjustment action and load change to be physically coupled within the same pulse width modulation cycle; the switching timing calculation unit extracts the zero vector execution duration within the current space voltage vector modulation cycle and reduces this zero vector execution duration to generate the adjustment compensation duration ΔT; the switching timing calculation unit obtains the first original execution duration of the first effective vector within the current sector. The second original execution time of the second effective vector The numerical ratio between the two is calculated; the switching timing calculation unit splits and adjusts the compensation duration ΔT according to the numerical ratio, outputs the first duration increment and the second duration increment, and injects the first duration increment and the second duration increment into the corresponding original execution duration respectively; the reconstructed first effective vector execution duration. Follow mathematical relationships ;in, This represents the execution time of the first valid vector after reconstruction. The original execution time represents the first valid vector. ΔT represents the original execution duration of the second effective vector, and ΔT represents the adjustment and compensation duration. The system limits the value of the adjustment and compensation duration to no more than 90% of the execution duration of the zero vector. The hardware comparison register inside the microcontroller receives the updated execution duration count value at a refresh frequency of no less than 10kHz.

[0041] When limiting the range of the adjustment compensation duration ΔT, the switching timing calculation unit determines the minimum reserved threshold for the zero vector execution duration based on the microcontroller's analog-to-digital conversion refresh frequency. If the margin after deducting the adjustment compensation duration ΔT from the initial zero vector execution duration in the space voltage vector modulation cycle is less than 10μs, the limiting protection unit blocks the increase of the adjustment compensation duration ΔT, ensuring that each space voltage vector modulation cycle has a zero vector period covering the current sampling window, maintaining the integrity of the closed-loop feedback link in the dynamic adjustment process of the electromechanical converter. The 10μs minimum reserved threshold is positively correlated with the hardware dead-time compensation time of the electromechanical converter's inverter bridge. The switching vector execution timing reconstruction step increases the amplitude of the space voltage vector synthesis while maintaining the constant phase of the stator space flux electrical angle. This is achieved by extracting the zero-crossing point of the stator current fundamental relative to the voltage vector in real time. The system calculates the current lag angle based on the lag time of the reference position. If the lag angle exceeds 0.05 rad, the system increases the magnitude of the synthesized voltage vector in 2% increments. By increasing the electromagnetic torque output, the system offsets the phase tail caused by load pulsation, thereby forcing the current vector to return to the preset phase axis. The phase deviation of the synthesized voltage vector before and after reconstruction is limited to a physical boundary of no more than 0.05 rad. The pulse width signal generation unit generates control signals for the on / off states of the power switches in the three-phase inverter bridge of the electromechanical converter based on the updated vector execution sequence. This control signal compensates for the stator current phase shift caused by the compressor load torque pulsation, while suppressing asynchronous harmonic currents and iron loss eddy currents in the stator windings. The output power of the electromechanical converter evolves into a counteracting energy flow that is opposite in direction and synchronized in time with the mechanical load fluctuation.

[0042] Example 2: In a single-rotor compressor performance test platform operating at a power frequency of 50Hz, the output current loop of the electromechanical converter is subjected to periodic pulsations of load torque caused by the eccentric rotation of the compressor crankshaft. A physical test platform with an independent dynamometer is selected, which applies an eccentric load command synchronized with the rotation of the compressor crankshaft. The transient current data source is a high-precision broadband current probe with a sampling frequency set to 100kHz. The bus current gradient acquisition unit uses a non-inductive sampling resistor with a resistance of no more than 5mΩ and a temperature drift coefficient of less than 50ppm / K as the current sensing entity. The analog-to-digital converter inside the controller performs differential sampling of the voltage drop across the non-inductive sampling resistor at a sampling rate of not less than 2 Mbit / s. The system corrects the gain bias caused by resistor heating by using piecewise linear compensation coefficients stored in non-volatile memory, ensuring that the output DC bus current gradient maintains dimensional consistency within the ambient temperature range of -20 degrees Celsius to 120 degrees Celsius. The differential acquisition circuit triggers the sample-and-hold logic at the midpoint of the power switch's conduction pulse, and suppresses the back electromotive force noise generated by the parasitic inductance of the bus through physical shielding and software digital filtering.

[0043] Step load commands with current change rates of 15.5 A / s, 32.4 A / s, and 48.2 A / s were applied to the physical test platform, and electromagnetic parameters were extracted within multiple consecutive space voltage vector modulation cycles. Under the load change condition of 32.4 A / s, the stator current phase lag of the control group reached 0.17 rad. A partially missing control group was introduced. This group deducted the zero vector when the DC bus current gradient was greater than the load change threshold, and the extracted adjustment compensation time ΔT was evenly distributed between the first and second effective vectors, instead of following the first original execution time. Compared with the second original execution time The numerical proportion allocation; the measured subspace flux linkage electric angle of the partially missing control group deflected by 0.12 rad; the bus current gradient acquisition unit of the present invention acquires the noisy transient current signal, and its internal oscillation interference suppression unit identifies the attenuation envelope center point of the high-frequency ringing signal of the bus current generated by the operation of the power switch, and triggers the sampling action within a preset time window after the attenuation envelope center point, and outputs the DC bus current gradient with interference filtered out; the switching timing calculation unit calculates the switching timing based on the first original execution time. Compared with the second original execution time The numerical proportional relationship is split to adjust the compensation time ΔT; under the sudden change condition of 48.2A / s, the stator current phase lag of the sample group of this invention converges to 0.04rad; the test data confirms that the effective vector expansion mechanism according to the original ratio and the zero vector subtraction mechanism have a synergistic effect in suppressing parasitic phase shift.

[0044] To define the physical boundary of the zero vector deduction ratio, a problem intensity gradient comparison system was constructed. The upper limit parameter of the adjustment compensation time ΔT of the out-of-range control group was set to 85%, 90%, and 95% of the initial zero vector execution time, respectively. The amplitude of asynchronous harmonic current within 500 consecutive pulse width modulation cycles was extracted, and the data showed nonlinear inflection point characteristics. When the upper limit parameter increased from 85% to 90%, the current trajectory tracking error monotonically decreased from 4.3% to 1.8%, indicating that the synthesized amplitude of the stator voltage vector covered the transient energy demand of the load pulsation. When the upper limit parameter crossed 90% to 95%, the current trajectory tracking error suddenly increased to 8.9%, and the voltage distortion rate caused by the inverter bridge dead zone effect increased to 12.7%. The upper limit parameter crossing 90% caused the sampling trigger window of the analog-to-digital converter inside the microcontroller to shrink, and the underlying hardware could not complete the current sampling action of the minimum freewheeling cycle, causing a data break in the feedback link. The nonlinear inflection point of the measured data verified that the upper limit of 90% is the deterministic operating range for maintaining volt-second balance and the sampling window of the underlying hardware.

[0045] Example 3: In a variable frequency heat pump compressor drive system operating at a low frequency of 15.5Hz, the output current loop of the electromechanical converter is affected by the superposition of mechanical pulsation and electromagnetic ringing interference caused by the operation of the power switch. The residual analysis unit collects the historical sequence of DC bus current gradient over ten consecutive mechanical cycles, calculates the dynamic standard deviation of the historical sequence, obtains the dimensionless structural coefficient characterizing the compressor rotor eccentricity, multiplies the dynamic standard deviation by the dimensionless structural coefficient, and outputs the load mutation threshold of the current space voltage vector modulation cycle. When the load mutation threshold is determined, the electromechanical converter is controlled to drive the compressor to run at no-load speed. The bus current gradient acquisition unit collects the raw data of DC bus current gradient over 100 space voltage vector modulation cycles, and the switching timing calculation unit calculates the arithmetic mean of the raw data. The load mutation threshold is set to the arithmetic mean, along with the standard deviation σ. The sum of three standard deviations σ is used to quantize and isolate random sensing noise and load fluctuation characteristics, where, σ is the arithmetic mean of the DC bus current gradient and the standard deviation of the DC bus current gradient. The oscillation interference suppression unit extracts the transient current high-frequency ringing sequence containing 512 discrete sampling points at the moment the power switch is turned on. The absolute values ​​of all discrete sampling points in the sequence are extracted to generate the energy distribution curve. The moving average filtering algorithm is applied to smooth the energy distribution curve to generate the attenuation envelope. The first-order difference sequence of the attenuation envelope is calculated, and the first zero-crossing point where the first-order difference sequence jumps from negative to positive is retrieved.

[0046] The oscillation interference suppression unit determines the time node corresponding to the first zero-crossing point as the attenuation envelope center point. This attenuation envelope center point characterizes the physical balance state of energy dissipation between the inverter bridge parasitic capacitance and the line inductance. When locating the attenuation envelope center point, the oscillation interference suppression unit uses a hardware capture register to record the sampling points of the high-frequency ringing signal of the bus current at the instant the power switch operates. It extracts the absolute value of the sampling points and generates an envelope curve by moving average filtering. It calculates the first-order difference sequence of the curve and retrieves the first zero-crossing moment when the value jumps from negative to positive. This moment is determined as the attenuation envelope center point characterizing the parasitic energy dissipation balance. Using the center point as the starting reference, the analog-to-digital converter is triggered to acquire the current signal within a 5.0μs time window to ensure that the output DC bus current gradient avoids electromagnetic interference in the transient oscillation region of the switch. The 5.0μs delay is determined by the sampling and holding time of the analog-to-digital converter. The bus current gradient acquisition unit uses the attenuation envelope center point as the starting time anchor point and calculates the attenuation envelope gradient within the attenuation envelope. Within a continuous 5.0μs time window after the center point, the analog-to-digital converter is controlled to acquire current signals and output the DC bus current gradient. When the current operating frequency is below 20.0Hz, the low-speed state sensing unit inserts an unbalanced pulse vector with a direct-axis voltage component amplitude greater than the quadrature-axis voltage component amplitude into the space voltage vector modulation cycle, acquires the actual DC bus current gradient under the excitation of the unbalanced pulse vector, calculates the vector deviation between the actual DC bus current gradient and the expected current gradient, multiplies the vector deviation by the preset flux linkage proportional coefficient, and outputs the rotor position angle error. The expected current gradient is derived from the ideal motor model based on the current voltage vector. The pulse width signal generation unit corrects the phase of the switching control signal based on the rotor position angle error. Within 1000 consecutive space voltage vector modulation cycles, the aforementioned load mutation threshold and attenuation envelope center point are applied to control the operation of the electromechanical converter. The measured stator current phase compensation residual converges to within the 0.02rad range.

[0047] In the abnormal load condition of instantaneous liquid slugging in a single-rotor compressor, the residual analysis unit inside the switching timing calculation unit initiates a range monitoring procedure for the DC bus current gradient. This residual analysis unit extracts the DC bus current gradient within five consecutive space voltage vector modulation cycles, retrieves the maximum and minimum values ​​in the sequence, and performs a subtraction operation to obtain the range of the DC bus current gradient. The range is compared with a preset rate of change threshold, which is set to 1.5 times the average range under steady-state conditions. When the range exceeds the rate of change threshold for two consecutive mechanical cycles, the system determines that there is incompressible fluid shock on the mechanical side and forcibly increases the lower limit percentage of the zero vector execution time. In this way, the system prevents the risk of deep magnetic circuit saturation caused by excessive expansion of the synthetic voltage vector amplitude by quantitatively characterizing the severity of the second-order fluctuation of the current waveform.

[0048] Example 4: In the factory test scenario of the variable frequency heat pump compressor drive system being connected to the electromechanical converter for the first time, the low-speed state sensing unit inside the main control chip executes the on-site deployment pre-calibration procedure for the reference parameters of the ideal motor model; the pulse width signal generation unit, with the compressor rotor in a stationary locked state, sequentially injects a direct-axis high-frequency step voltage and a quadrature-axis high-frequency step voltage with an amplitude of 10% of the rated voltage into the three-phase inverter bridge; the bus current gradient acquisition unit simultaneously collects the direct-axis transient current response slope and the quadrature-axis transient current response slope under this specific excitation; the system calculates and extracts the direct-axis equivalent inductance of the current physical body according to the division relationship between the measured voltage excitation amplitude and the current response slope. equivalent inductance of cross axis ;in, Represents the direct-axis equivalent inductance. Representing the quadrature-axis equivalent inductance, the system calculates the steady-state voltage drop by injecting a constant DC current to obtain the stator equivalent resistance. The system will extract the direct-axis equivalent inductance mentioned above. Cross-axis equivalent inductance and stator equivalent resistance They are written together into non-volatile memory and converted into core calculation parameters for an ideal motor model.

[0049] After the compressor enters the operating state, the low-speed state sensing unit derives the expected current gradient based on the core calculation parameters embedded in the non-volatile memory and the real-time acquired current voltage vector. This expected current gradient serves as the mathematical benchmark for calculating the actual DC bus current gradient response deviation and participates in the extraction calculation of rotor position angle error. During the low-speed operation phase, the system periodically injects an unbalanced detection pulse with a duration of 60us every 10ms. The amplitude of this pulse is locked at 15% of the real-time monitored value of the DC bus voltage. By comparing the 3.5A / s step difference of the current gradient at the pulse injection moment, the current rotor salient pole position is obtained by looking up a table, thus providing an accurate angle feedback benchmark under sensorless conditions. The physical quantization mapping chain established by the pre-calibration procedure is used to eliminate the initial baseline loss problem introduced by winding manufacturing tolerances and nonlinear characteristics of magnetic circuit materials. The microcontroller outputs a switching control signal according to the correction command including rotor position angle error to compensate for stator current phase offset. The electromechanical converter enters a steady-state operating state with adaptive matching capability for the hardware discreteness of different batches of compressors.

[0050] Example 5: In a production line deployment scenario with multi-model compatible compressor controllers, the system faces rotor assemblies with different magnetic circuit saturation characteristics; the verification engineer implements a calibration procedure for the model baseline parameters, with the compressor rotor at an idle speed of [missing information]. Under steady-state operation, the switching timing calculation unit sequentially injects a set of test voltage vectors with fixed count steps into the three-phase inverter bridge, and records the original current gradient response sequence fed back by the bus current gradient acquisition unit; the residual analysis unit uses the least squares fitting algorithm to process the original current gradient response sequence and extract the physical feature slope. The program calculates the deviation ratio between the slope of this physical characteristic and the theoretically derived value of the ideal motor model, defines it as the flux linkage ratio coefficient for the current hardware batch, and writes it into the register address space of non-volatile memory. This program quantifies the gain drift introduced by the permeability deviation of the stator core material and the inconsistency of winding mutual inductance, providing a physical correction benchmark for performing vector reconstruction operations. The reference no-load speed during the calibration process, The slope is the measured physical characteristic slope.

[0051] The low-speed state sensing unit receives ambient temperature fluctuations exceeding When the trigger signal reaches ℃, the preset temperature-varying inductance compensation mapping table in the non-volatile memory is invoked to adjust the stator equivalent resistance in the ideal motor model. Reconstruction is performed; the switching timing calculation unit calculates the original execution duration of the first valid vector within the current sector. The second original execution time of the second effective vector Retrieve the corresponding conformal transformation factor and apply it according to mathematical relationships. The system performs vector duration reallocation; the pulse width signal generation unit completes a single-cycle refresh of the duty cycle count value through the overload event of the microcontroller hardware comparison register; the updated vector execution sequence compensates for the current hysteresis angle caused by load mutation under the physical constraint of maintaining the constant stator flux spatial electrical angle; the system enters a closed-loop steady-state operation state in which the phase difference between the electromagnetic torque energy output and the mechanical side load pulsation peak converges to the physical boundary of 0.01 rad.

[0052] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit of this application and the scope of protection of this invention, and all of these forms are within the protection scope of this application.

Claims

1. A compressor-driven electromechanical converter regulating system, characterized in that, include: The bus current gradient acquisition unit is used to acquire the DC bus current gradient, which characterizes the periodic load torque fluctuation characteristics of the compressor, by collecting the transient current signal of the sampling resistor on the DC bus side of the electromechanical converter. The switching timing calculation unit is connected to the bus current gradient acquisition unit and is used to reconstruct the switching vector execution timing within the space voltage vector modulation period based on the DC bus current gradient. The pulse width signal generation unit is used to generate control signals for the on / off states of power switches in the three-phase inverter bridge of the electromechanical converter based on the timing sequence of the reconstructed switching vector. When the switching timing calculation unit determines that the DC bus current gradient exceeds the preset load change threshold, it initiates a reallocation operation for the zero vector idle period, which specifically includes: reducing the zero vector execution duration within the current space voltage vector modulation cycle to obtain the adjustment compensation duration; The switching timing calculation unit identifies the first original execution duration of the first effective vector and the second original execution duration of the second effective vector within the current sector. Based on the numerical ratio between the first and second original execution durations, it splits the adjustment compensation duration into a first duration increment and a second duration increment. The first duration increment is injected into the first original execution duration, and the second duration increment is injected into the second original execution duration to generate an updated vector execution sequence. Under the physical constraint of maintaining the constant electrical angle phase of the stator space flux linkage, the unit compensates for the stator current phase shift caused by the compressor load torque pulsation by increasing the composite amplitude of the space voltage vector.

2. An electromechanical converter regulating system for a compressor drive according to claim 1, characterized in that The bus current gradient acquisition unit includes an oscillation interference suppression unit. The oscillation interference suppression unit is used to identify the attenuation envelope center point of the high-frequency ringing signal of the bus current generated by the operation of the power switch, and to trigger a sampling action within a preset time window after the attenuation envelope center point to obtain the DC bus current gradient.

3. An electromechanical converter regulator system for a compressor drive as recited in claim 1, wherein, The switching timing calculation unit includes a low-speed state sensing unit. When the compressor operating frequency is lower than a preset frequency threshold, the low-speed state sensing unit inserts an unbalanced pulse vector into the space voltage vector modulation period and calculates the rotor position angle based on the response deviation of the DC bus current gradient to the unbalanced pulse vector. The pulse width signal generation unit corrects the phase of the switching control signal based on the rotor position angle.

4. The electromechanical converter regulation system for compressor drive according to claim 1, characterized in that, The switching timing calculation unit includes a residual analysis unit, which monitors the range of the DC bus current gradient within multiple consecutive space voltage vector modulation cycles, and outputs a carrier frequency switching command for the pulse width signal generation unit when the range exceeds a preset rate of change threshold.

5. The electromechanical converter regulation system for compressor drive according to claim 1, characterized in that, When the switching timing calculation unit performs the duration increment operation of the first effective vector, let the space voltage vector modulation period be... The original execution time of the first valid vector in the current sector is The original execution time of the second effective vector is The execution time of the zero vector is If the compensation duration is adjusted to ΔT, then the execution time of the first effective vector after reconstruction is... Follow these rules: Where ΔT takes a value no greater than 90%.

6. The electromechanical converter regulation system for compressor drive according to claim 1, characterized in that, The switching timing calculation unit maintains the ratio of the increase in the first effective vector to the increase in the second effective vector in line with the original duration ratio of the first effective vector to the second effective vector, thus limiting the phase deviation between the reconstructed composite voltage vector and the unreconstructed composite voltage vector to no more than 0.05 rad.

7. The electromechanical converter regulation system for compressor drive according to claim 1, characterized in that, The system also includes a bus voltage monitoring unit for acquiring DC bus voltage dip values; and a switching timing calculation unit for adjusting the gain coefficient of the compensation duration based on the DC bus voltage dip value.

8. The electromechanical converter regulation system for compressor drive according to claim 1, characterized in that, The switching timing calculation unit includes a limiting protection unit to block further increases in the adjustment compensation time when the zero vector execution time is compressed to 10μs, in order to maintain the volt-second balance within the space voltage vector modulation period.

9. The electromechanical converter regulation system for compressor drive according to claim 1, characterized in that, The system also includes a thermal drift calibration unit, which is used to obtain the real-time temperature of the sampling circuit in the bus current gradient acquisition unit, and output calibration coefficients to the switching timing calculation unit according to the preset temperature-resistance characteristic curve to correct the quantization amplitude of the DC bus current gradient.

10. The electromechanical converter regulation system for compressor drive according to claim 1, characterized in that, The pulse width signal generation unit is connected to the hardware comparison register of the microcontroller. The duty cycle of the PWM waveform is adjusted by rewriting the count value of the hardware comparison register at the update node of the space voltage vector modulation cycle.

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