CN-121984396-A - Control system for reducing low-temperature starting impact of air energy equipment

CN121984396ACN 121984396 ACN121984396 ACN 121984396ACN-121984396-A

Abstract

The invention relates to the technical field of power supply and control, and discloses a control system for reducing low-temperature starting impact of air energy equipment, which comprises a variable-frequency power driving unit, an electric signal acquisition unit and a logic control processing unit, wherein the logic control processing unit is used for injecting a frequency scanning to a multiphase inductive load stator winding in a low-temperature starting stage, and calculating an equivalent impedance change characteristic value in real time according to current response, and switching to a closed-loop vector driving mode when the characteristic value is monitored to generate a second derivative inflection point representing medium damping transition.

Inventors

ZHANG BO
MA LEI
Sun Naizhuang
LI HAICHAO

Assignees

青岛海盎暖通设备有限公司

Dates

Publication Date: 20260505
Application Date: 20260211

Claims (10)

1. A control system for reducing cold start shock of an air energy plant, comprising: the variable frequency power driving unit is used for outputting a controlled modulation voltage vector to a multiphase inductive load stator winding of the system; the electric signal acquisition unit is used for acquiring three-phase current response data of the multiphase inductive load stator winding in real time; The logic control processing unit is used for executing a control program, when a starting instruction is received and the initial environment temperature of the system is detected to be lower than a preset cold starting threshold value, the logic control processing unit is used for controlling the variable frequency power driving unit to enter a pre-adjustment mode, injecting a beam of frequency into a multiphase inductive load stator winding to execute linear slope scanning, injecting an alternating axis oscillating current sequence with amplitude clamped below a rotor physical action threshold value based on real-time rotor position feedback so as to construct a high-frequency alternating electromagnetic field between a stator iron core and a rotor permanent magnet, simultaneously resolving an equivalent impedance change characteristic value representing the rheological state of viscous medium inside a load in real time according to three-phase current response data fed back by the electric signal acquisition unit, judging that the pre-adjustment is completed and immediately instructing the variable frequency power driving unit to switch to a closed loop vector driving mode to drive the rotor to rotate when the second derivative point representing the transition of the medium from a high damping state appears at the time change rate of the monitored equivalent impedance change characteristic value.
2. The control system for reducing low-temperature starting shock of air energy equipment according to claim 1, wherein the logic control processing unit is used for calculating the current dynamic impedance module according to the following transfer function relation according to the quadrature axis voltage command value output by the variable frequency power driving unit and the quadrature axis current feedback value acquired by the electrical signal acquisition unit when calculating the equivalent impedance change characteristic value : , wherein, For the magnitude of the change in quadrature voltage command value at the current sweep frequency, The response amplitude of the quadrature current feedback value at the corresponding frequency is obtained.
3. The system of claim 1, wherein the logic for performing linear ramp by the variable frequency power drive unit is to continuously modulate at a constant rate of change of frequency to a predetermined cutoff frequency starting from a predetermined start frequency, the start frequency being set higher than the grid frequency and the cutoff frequency being set lower than the upper limit of the switching frequency of the variable frequency power drive unit.
4. The system of claim 1, wherein the logic control processing unit is configured to obtain rotor position information corresponding to the stator windings of the multiphase inductive load in real time and limit peaks of the quadrature current sequence to a range of 30% to 50% of a minimum critical current value that causes mechanical displacement of the rotor to maintain the rotor in a physically stationary state in the preconditioning mode.
5. The control system for reducing low-temperature starting shock of air energy equipment according to claim 1, wherein the logic control processing unit executes sliding window differential operation when judging the inflection point of the second derivative, the logic control processing unit compares the first derivative of the equivalent impedance change characteristic value in the current time window with the first derivative of the previous time window, and confirms the occurrence of the inflection point of the second derivative when the slope change value displayed by the comparison result exceeds a preset phase change identification threshold value and the duration is longer than a preset anti-disturbance period.
6. The control system for reducing low-temperature starting impact of air energy equipment according to claim 1, further comprising a direct current bus voltage monitoring unit connected with the logic control processing unit, wherein the logic control processing unit is further used for monitoring a bus voltage fluctuation value fed back by the direct current bus voltage monitoring unit in real time during a pre-conditioning mode, establishing a negative feedback control loop according to the bus voltage fluctuation value and dynamically adjusting the injection duty ratio of the quadrature axis oscillating current sequence.
7. The control system for reducing low-temperature starting shock of air energy equipment according to claim 1, wherein the variable-frequency power driving unit comprises an intelligent power module and a grid driving circuit connected with the intelligent power module, the logic control processing unit controls the switching state of the intelligent power module by sending a high-frequency pulse width modulation signal to the grid driving circuit so as to synthesize a quadrature axis oscillating current sequence, and the carrier frequency of the high-frequency pulse width modulation signal is set to maintain an asynchronous relation with the scanning frequency of the quadrature axis oscillating current sequence in a non-integer multiple manner so as to inhibit specific subharmonic resonance.
8. The control system for reducing cold start shock of air energy equipment according to claim 1, wherein the logic control processing unit executes a zero-current soft switching strategy when switching to a closed-loop vector driving mode is instructed, wherein the amplitude of the quadrature axis oscillating current sequence is decayed to zero exponentially, and after confirming that the stator current passes through the zero point, the integral term of the vector control algorithm is reset, and the quadrature axis current for generating the start torque is applied with a direct axis current capable of establishing a rotor flux linkage as an initial excitation.
9. The control system for reducing low-temperature starting shock of air energy equipment according to claim 1, wherein the control system further comprises a nonvolatile storage unit for storing reference impedance curves of the multiphase inductive load at different temperatures, and the logic control processing unit is further used for reading the reference impedance curve corresponding to the current environment temperature before each starting, performing deviation verification on the equivalent impedance change characteristic value calculated in real time and the reference impedance curve, and outputting a fault locking instruction and prohibiting entering a closed-loop vector driving mode when the deviation value exceeds a preset safety limit.
10. The control system for reducing low-temperature starting impact of air energy equipment according to claim 1, wherein the electric signal acquisition unit comprises a three-phase Hall current sensor arranged at the output end of the variable-frequency power driving unit and a signal conditioning circuit arranged at the rear end, and the signal conditioning circuit is used for performing anti-aliasing filtering processing on the acquired analog current signal and converting the processed signal into digital quantity to be input to a direct memory access interface of the logic control processing unit.

Description

Control system for reducing low-temperature starting impact of air energy equipment Technical Field The invention relates to a control system for reducing low-temperature starting impact of air energy equipment, and belongs to the technical field of safety control of efficient energy-saving air energy heat pumps and refrigeration systems. Background In the low-temperature application scene of the air source heat pump equipment at present, the starting performance of the permanent magnet synchronous compressor is directly related to the energy efficiency ratio, the running reliability and the service life of the whole heat pump circulation system, especially in extremely cold environment, the abnormal surge of the system energy consumption is often caused by the uncertainty of the internal fluid state of the compressor, the existing drive control technology generally adopts a stator winding direct current injection heating or shell external electric heating mode to preheat the compressor, the viscosity of lubricating oil is reduced by raising the integral temperature, the motor is driven to rotate and start according to a preset voltage frequency curve, however, the mixture of lubricating oil and refrigerant in the compressor presents thixotropic non-Newtonian fluid characteristics at extremely low environmental temperature, the heat conduction efficiency is limited by the static thermal resistance of a medium, the temperature rise of a stator winding is often faster than the transition of the physical phase state of an oil film in a kinematic pair gap, the existing control logic can not penetrate through a sealed shell to directly sense the real rheological state of a lubricating medium, the asynchronous performance of the thermal response enables the motor rotor oil film to be executed when still in a high shear modulus semi-solid state, the transient state is not easy to generate a time-to trigger the transient state of the lubricating medium, the transient power module is not triggered, and the mechanical failure occurs due to the transient power module is prevented from being damaged. The prior art starting control strategy has logic dead zone, excessively depends on preset time sequence rather than real-time state feedback, and the Chinese patent application with publication number CN106482412A discloses a heat pump unit and a low-temperature starting method and device for a compressor thereof, which solve the problem of difficult low-temperature starting through a sectional starting strategy, wherein the logic is to firstly control the compressor to start in a first mode and stop after running for a preset time, delay the start in a second mode and finally enter normal running; in addition, the existing variable frequency driving strategy mainly focuses on the electromagnetic torque output capability of the motor body, but does not bring thermodynamic dynamic response of the refrigeration cycle system into a closed loop boundary of starting control, and in the frequency climbing stage, if the establishment process of the suction rate of the compressor is not constrained by the change rate of suction pressure, the pressure drop rate in the gas-liquid separator is extremely easy to exceed the gasification rate of the refrigerant, and the transient abrupt change of the pressure can induce severe flash and bumping of the refrigerant, so that a large amount of gas-liquid mixture is sucked into a compressor pump body, a hysteresis liquid impact phenomenon is caused, and the mechanical integrity of core components such as a vortex plate is threatened. Therefore, how to construct a medium phase state recognition mechanism based on electric signal feedback and establish self-adaptive driving logic fused with thermodynamic boundary constraint so as to realize the impact-free smooth starting of the compressor becomes the technical problem to be solved by the invention. Disclosure of Invention In order to solve the problems in the background technology, the technical scheme of the invention is as follows, a control system for reducing low-temperature starting impact of air energy equipment, comprising: the variable frequency power driving unit is used for outputting a controlled modulation voltage vector to a multiphase inductive load stator winding of the system; the electric signal acquisition unit is used for acquiring three-phase current response data of the multiphase inductive load stator winding in real time; The logic control processing unit is used for executing a control program, when a starting instruction is received and the initial environment temperature of the system is detected to be lower than a preset cold starting threshold value, the logic control processing unit is used for controlling the variable frequency power driving unit to enter a pre-adjustment mode, injecting a beam of frequency into a multiphase inductive load stator winding to execute linear slope scanning, injecting an alternating