Three-phase motor low-power-consumption driving control system and method based on state perception and multimode switching

Abstract

The invention discloses a three-phase motor low-power-consumption driving control system and method based on state perception and multi-mode switching, and the method comprises the steps: monitoring the operation state of a motor in real time, setting the threshold values of rotating speed, current and the like, dividing the motor into a standby / light load state, a maintenance operation state, a steady-state high-speed operation state and a disturbance / acceleration / deceleration state, and matching corresponding control modes according to different states. For example, a single-phase alternate power-on mode is adopted for standby / light load, a double-phase alternate power-on mode is adopted for maintenance operation, a limited duty ratio PWM control mode is adopted for steady-state high-speed operation, and a full FOC closed-loop control mode is adopted for disturbance / acceleration and deceleration. Intelligent switching is performed based on real-time state judgment of the motor, system power consumption can be remarkably reduced in light load, low speed or standby states and the like, the problem of high energy consumption of a traditional control strategy in a low-power-consumption scene is effectively solved, and energy saving is remarkable.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of three-phase motor control, and particularly relates to a three-phase motor low-power driving control system and method based on state sensing and multi-mode switching. BACKGROUND

[0002] At present, three-phase permanent magnet synchronous motors (PMSM) have been widely used in industrial servo, electric vehicles, intelligent terminals and energy-saving home appliances, and their driving systems generally adopt the Field-Oriented Control (FOC) strategy based on vector control theory. With the help of real-time coordinate transformation and current double-loop control, the relative direction of the motor stator magnetic field and the rotor magnetic field can be accurately controlled, thereby realizing high dynamic performance, high torque density and high-speed running capability.

[0003] In the traditional FOC control method, three-phase voltage signals are usually generated by SVPWM (Space Vector Pulse Width Modulation) to drive the inverter to make the three-phase winding in the energized state at any time. Although this method can form a continuous and smooth rotating magnetic field and achieve excellent electromagnetic torque output characteristics, it also brings many problems: First, the energy consumption is high. The three-phase full-time energization makes the stator winding always have current flowing, resulting in high system power consumption, which is not conducive to the operation in low-power scenarios such as light load and standby; Second, the control system is complex, requiring accurate current sampling, encoder feedback and vector transformation operations, which requires high controller resources and system response; Third, it is not suitable for some minimalist application scenarios, such as small-power IoT terminals, electric tools, smart home devices, etc. The control precision requirement is not high, and more attention is paid to power consumption and cost. The traditional FOC scheme is not economical and applicable.

[0004] To reduce control complexity and power consumption, some research attempts to introduce a "simplified driving strategy", such as single-phase rotation energization method, that is, only one phase of the three-phase winding is energized at each time, and the energized phase is switched in fixed angular steps (such as 60 electrical degrees) rotationally. This method is simple in structure and low in power consumption, and is suitable for light load operation.

[0005] However, such simplified control methods have obvious defects: the magnetic field is discontinuous, the torque fluctuation is large, and a standard rotating magnetic field cannot be formed, resulting in significant vibration and noise during operation; the low-speed or high-speed running capability is poor, the control bandwidth is insufficient, and it is difficult to adapt to high dynamic load changes; and it cannot support advanced control functions such as field weakening speed expansion and fine speed control, limiting the application scenarios.

[0006] In summary, the existing technical solutions have "two polarized" problems: the traditional FOC control strategy has superior performance but high power consumption, and the simplified control strategy has low power consumption but insufficient performance. SUMMARY

[0007] In order to solve the above problems, the application provides a three-phase motor low-power driving control system and method based on state sensing and multi-mode switching, which can simultaneously consider energy saving and operation stability.

[0008] Therefore, the technical scheme of the application is as follows: a three-phase motor low-power driving control method based on state sensing and multi-mode switching, comprising the following steps: 1) Real-time monitoring of motor operating state, and classification of current working condition according to preset criteria; 1.1) State threshold is set in advance, and real-time detection data is compared with the state threshold; 1.2) According to the comparison result, the motor working state is divided into standby / light load state, maintenance running state, steady-state high-speed running state and disturbance / speed-up and deceleration state; 2) According to the motor working state, the corresponding control mode is matched, that is: In the standby / light load state, single-phase rotation power supply mode is adopted; In the maintenance running state, double-phase alternating power supply mode is adopted; In the steady-state high-speed running state, limited duty ratio PWM control mode is adopted, and SVPWM technology is used to control three-phase output; In the disturbance / speed-up and deceleration state, full FOC closed-loop control mode is adopted.

[0009] On the basis of the above scheme and as a preferred scheme of the above scheme, in step 1), the following are set in advance: Speed threshold , , and > Current threshold , , and > Electromagnetic torque change rate threshold Speed change rate threshold ; The motor working state judgment conditions are as follows: Standby / light load state determination: And ; Maintenance running state determination: And ; Steady-state high-speed running state determination: And ; Disturbance / speed-up and deceleration state determination: Or ; Wherein: is the real-time rotating speed of the motor; is the root mean square value of the three-phase current; is the electromagnetic torque change rate; is the rotating speed change rate.

[0010] On the basis of the above scheme and as a preferred scheme of the above scheme: the priority of the disturbance / acceleration and deceleration state determination is higher than the remaining three states, that is, when the motor operating state meets the disturbance / acceleration and deceleration state determination condition, the full FOC closed-loop control mode is forcibly switched.

[0011] On the basis of the above scheme and as a preferred scheme of the above scheme: the standby / light load state, the steady-state high-speed operating state, and the steady-state high-speed operating state can all be set with a hysteresis interval and a mode retention time threshold; and the disturbance / acceleration and deceleration state can be set with a mode retention time threshold.

[0012] On the basis of the above scheme and as a preferred scheme of the above scheme: the single-phase turn-by-turn energization mode is that only one of the U, V or W phase is turned on at any time; the energization sequence is determined according to the rotor electric angle partition, and a table lookup method or an angle determination method can be used.

[0013] On the basis of the above scheme and as a preferred scheme of the above scheme: the two-phase alternate energization mode is that two phases are turned on at the same time to form a more continuous magnetic field; the electric angle space is divided into multiple sectors, and torque is generated by two-phase winding energization in each sector; a transition interval is set at the sector boundary to make the two-phase energization control of adjacent sectors overlap to a certain extent.

[0014] On the basis of the above scheme and as a preferred scheme of the above scheme: the limited duty ratio PWM control mode limits the output voltage value by using dynamic adjustment of the duty ratio or limiting the output voltage amplitude.

[0015] Another technical scheme of the application is: a three-phase motor low-power consumption driving control system based on state perception and multi-mode switching, comprising: a state recognition module: for real-time monitoring of the motor operating state, and classifying the current motor working state according to a preset criterion; a mode selection module: embedded with a state machine or a decision tree structure, taking the output of the state recognition module as an input signal, and performing control mode matching on the current working state of the motor; a plurality of driving strategy modules: for storing different motor control logics; a motor control module: for controlling the on-off of the three-phase motor; The mode selection module can trigger the corresponding driving strategy module through mutual exclusion scheduling logic, and the motor control module controls the driving of the three-phase motor according to the retrieved control logic.

[0016] As a preferred scheme of the above scheme and on the basis of the above scheme: the categories in the state recognition module are divided into standby / light load state, steady state high speed running state, steady state high speed running state, disturbance / acceleration and deceleration state; the drive strategy module includes single-phase turn-on strategy, double-phase alternating turn-on strategy, limited duty ratio PWM control strategy and full FOC closed loop control strategy, and one-to-one correspondence.

[0017] Compared with the prior art, the present application has the following advantages: On the basis of the traditional FOC control mode, the present application introduces a plurality of low-power consumption control strategies such as single-phase turn-on, double-phase alternating turn-on and limited duty ratio SVPWM, and intelligently switches based on real-time motor state judgment, which can significantly reduce system power consumption in light load, low speed or standby state, effectively solve the high energy consumption problem of traditional control strategy in low power consumption scene, and save energy significantly.

[0018] The present application matches the control strategy reasonably in different operating states, such as using double-phase alternating turn-on mode to form a more continuous magnetic field at medium speed, and using full FOC closed loop control mode at high speed, so that the system ensures running stability while saving energy, and improves overall performance and user experience.

[0019] The present application monitors and judges the motor operating state in real time based on motor speed, current root mean square value, electromagnetic torque change rate, speed change rate and other physical variables, automatically matches the most suitable control mode without human intervention, has strong environmental adaptability and anti-disturbance ability, and can better meet the needs of different working conditions.

[0020] The present application uses a relatively simple control mode in standby / light load, maintenance running and other states, reduces the dependence on accurate current sampling, encoder feedback and complex vector transformation operation, reduces the requirements for controller resources and system response, and makes the system applicable to more resource-limited application scenarios.

[0021] The control system of the present application can be realized through a state machine or a decision tree structure, is suitable for a variety of embedded platforms, has a clear control strategy module structure, can be independently realized, has good scalability and maintainability, is convenient for actual engineering deployment, and can be widely applied to industrial servo, electric vehicles, intelligent terminals, energy-saving home appliances and many other scenes, especially in power-sensitive and certain control precision required occasions.

[0022] In the multi-mode switching process of the present application, hysteresis interval, mode retention time threshold, soft transition and torque smooth change are introduced to prevent the sudden change of drive signal, avoid system impact or current overshoot, and further protect the safety and running continuity of the system. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Flow chart of the method of the present application. DETAILED DESCRIPTION

[0024] Example 1 The three-phase motor low-power driving control method based on state awareness and multi-mode switching described in this example includes the following steps: 1) Real-time monitoring of motor operating state, and classification of current working condition according to preset criteria; 1.1) State threshold values are set in advance, including but not limited to: rotational speed threshold , , and > ; current threshold , , and > ; electromagnetic torque change rate threshold , rotational speed change rate threshold ; The above-mentioned state threshold values can be set according to actual working experience and can be configured according to different applications, for example, = 100 rpm, = 600 rpm, = 0.2A, = 1.2A, = 0.3 A / ms, = 0.05 Nm / ms.

[0025] 1.2) Comparing real-time detection data with state threshold values, and classifying motor operating state according to comparison results into standby / light load state, maintaining running state, steady-state high-speed running state, and disturbance / acceleration / deceleration state; Motor operating state judgment conditions are as follows: Standby / light load state S1 judgment: and ; Maintaining running state S2 judgment: and ; Steady-state high-speed running state S3 judgment: and ; Disturbance / acceleration / deceleration state S4 judgment: or ; Wherein: is the real-time rotational speed of the motor; is the root mean square value of three-phase current; is the electromagnetic torque change rate; For the rate of change of speed.

[0026] According to the motor operating state, the corresponding control mode is matched, that is: ① In standby / light load state S1, control strategy A: single-phase turn-by-turn energization mode is enabled; The single-phase turn-by-turn energization mode (energy-saving priority) is that only one of U, V or W phase is turned on at any time; the energization sequence is determined according to the rotor electric angle partition (for example, every 60°); the table lookup method or angle judgment method can be used to realize it.

[0027] Table lookup method: The control logic of the control strategy A is simple, the system power consumption is the lowest, and it is suitable for standby or light load maintenance running state.

[0028] ② In the maintenance running state S2, control strategy B: dual-phase alternating energization mode is enabled; The dual-phase alternating energization mode (considering power consumption and stability) is that two phases are turned on at the same time to form a more continuous magnetic field; there is a certain overlap in the two-phase conduction in each sector; in the control mode of control strategy B, the electric angle space is divided into multiple sectors, and torque is generated by two-phase winding conduction in each sector. In order to reduce the torque fluctuation in the switching process, a transition interval is set at the boundary of the sector, so that there is a certain overlap in the two-phase conduction control of adjacent sectors, realizing soft transition of control state and smooth change of torque.

[0029] For example: The control strategy B has a more stable torque output than the control strategy A; the control complexity is still lower than FOC, and it can be applied to low-speed, medium-speed and light-load running.

[0030] ③ In the steady-state high-speed running state S3, control strategy C: limited duty ratio PWM control mode is enabled; The limited duty ratio PWM control mode (steady-state energy saving) uses SVPWM technology to control three-phase output; the output voltage can be adjusted by dynamically adjusting the duty ratio or limiting the output voltage amplitude, so as to reduce the current amplitude and inverter switching loss; the control strategy C is suitable for energy-saving scenes in steady-state running without full performance.

[0031] The dynamic adjustment of the duty ratio is to limit the maximum duty ratio of the PWM waveform (such as not more than 80%), control the average value of the inverter output voltage, and thus reduce the overall energy consumption of the motor. In the system in the high-speed light load, steady-state cruising and other non-high-performance demand stages, the dynamic reduction of the modulation ratio range effectively suppresses unnecessary energy output, achieving energy-saving effect. This mechanism can be realized by reference voltage adjustment or modulation ratio limiting, and has the characteristics of simple realization and flexible response.

[0032] Limiting the output voltage amplitude: the amplitude of the output voltage vector in the FOC algorithm is limited, and if the combined amplitude exceeds the preset upper limit (such as the maximum allowed voltage amplitude), the components are scaled in proportion, the voltage direction is kept unchanged, and the energy output is controlled. This method can effectively prevent over-voltage driving in steady state or light load, reduce invalid power consumption, and at the same time improve system safety and electrical stability.

[0033] ④ When the disturbance / acceleration / deceleration state S4 occurs, forcibly switch to control strategy D: full FOC closed-loop control mode.

[0034] The full FOC closed-loop control mode is the existing full three-phase closed-loop driving mode, which includes Park / Clarke transformation, current inner loop, speed outer loop, and SVPWM; it can provide optimal control accuracy and dynamic response, and is used for large load changes, high speed, and high precision control stages.

[0035] Among them, the priority of disturbance / acceleration / deceleration state determination is higher than that of the other three states, that is, when the motor operating state meets the disturbance / acceleration / deceleration state determination condition, it is forcibly switched to the full FOC closed-loop control mode. This also means that even if it is currently in energy-saving mode, it will immediately switch to full FOC mode to ensure stability and fast response. The other three state adjustments can be adjusted, and the switching can be switched gently.

[0036] At the same time, in order to avoid frequent mode jitter, the system can set a hysteresis interval and a mode holding time threshold. The hysteresis interval refers to an upper and lower tolerance band set to prevent frequent switching caused by small disturbances when the operating state is close to the control mode switching threshold. Only when the operating parameters continuously exceed the interval boundaries, the control mode switching is allowed.

[0037] The mode holding time threshold refers to the minimum time that a control mode must be activated before it can be switched to another control mode. For example: The hysteresis interval of control strategy A is set to: speed ±10 rpm, current RMS ±0.02 A; the mode holding time threshold is greater than or equal to 200 ms; The hysteresis interval of control strategy B is set to: speed ±20 rpm, current RMS ±0.05 A; the mode holding time threshold is greater than or equal to 300 ms; The hysteresis interval of control strategy C is set to: speed ±50 rpm, electromagnetic torque slope ±2% / ms; the mode holding time threshold is greater than or equal to 400 ms; Control strategy D can not set the hysteresis interval, or set to ±5 rpm, current RMS ±0.02 A (only as a cut out judgment); mode retention time threshold ≥ 1000 ms (forced lock).

[0038] Example: hysteresis logic of speed triggered mode switching Assuming that the switching threshold of state S1→state S2 is 120 rpm, and the hysteresis is set to ±10 rpm: if the current speed is decelerated from state S2, it is allowed to switch back to state S1 only when the speed is <110 rpm (switching threshold 120 - hysteresis 10); if the current speed is accelerated from state S1, it is allowed to switch to state S2 only when the speed is >130 rpm (switching threshold 120 + hysteresis 10); to avoid frequent jitter due to speed fluctuation in the interval of 119~121 rpm, prevent sudden changes in drive signals, avoid system impact or current overshoot, and further ensure system safety and operational continuity.

[0039] Embodiment 2 The three-phase motor low-power drive control system based on state perception and multi-mode switching described in this embodiment comprises: 1. State recognition module: used for real-time monitoring of motor operating state, and classifying the current motor operating state according to preset criteria; various sensors can be used to monitor the motor running process, for example: 2. Control mode selection and switching mechanism: the output of the state recognition module will be input into the mode selection module. The module is embedded with a state machine or decision tree structure, which matches the control mode for the current state, and triggers the corresponding drive strategy module through mutual exclusion scheduling logic. According to the set threshold (such as speed, current, electromagnetic torque slope), a decision tree / state machine is established to realize automatic mode switching, ensure smooth and stable drive mode switching, avoid oscillation and instability caused by frequent switching, and be easy to implement in engineering and deploy on MCU / FPGA.

[0040] 3. Multiple drive strategy modules include single-phase rotationally energized strategy A, two-phase alternately energized strategy B, limited duty ratio PWM control strategy C, and full FOC closed-loop control strategy D, to realize the lowest power consumption in standby, low-speed, and light-load states; independent of flux observer or high-frequency injection, simple structure; compatible with traditional FOC on the same platform.

[0041] 4. Control mode smooth switching and protection mechanism: linear interpolation, hysteresis interval, and other methods are used to smoothly switch the drive signal, reduce current spikes and flux jumps, prevent electromagnetic interference and mechanical impact caused by switching, and ensure the stability and reliability of the system in actual deployment.

[0042] The switching delay mechanism refers to introducing a delay confirmation time when the control mode is about to switch, and only when the switching condition is continuously valid for more than a set time threshold (such as 200 ms), the control mode switching is allowed to be executed, thereby avoiding frequent jitter caused by transient disturbance or measurement noise.

[0043] The smooth transition function refers to using a smooth function (such as a linear transition, an exponential function, or an S-shaped function) to transition the key control variables (such as the voltage reference value, the PWM duty cycle) when the control mode switches, ensuring that the output changes continuously, gradually, and without sudden changes, and improving system stability and control quality.

[0044] The above only describes the preferred embodiments of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiments. Any technical solutions falling within the concept of the present application shall fall within the protection scope of the present application. It should be noted that, for ordinary skilled persons in the art, some improvements and refinements without departing from the principles of the present application shall also be considered as the protection scope of the present application.

Claims

1. A low-power drive control method for a three-phase motor based on state perception and multi-mode switching, characterized in that: Includes the following steps: 1) Monitor the motor's operating status in real time and classify the current operating conditions according to preset criteria; 1.1) Set a state threshold in advance and compare the real-time detection data with the state threshold; 1.2) Based on the comparison results, the motor operating states are divided into: standby / light load state, maintenance operation state, steady-state high-speed operation state, and disturbance / acceleration / deceleration state; 2) Match the corresponding control mode according to the motor's operating state, that is: In standby / light load mode, a single-phase alternating power supply mode is used; When maintaining operation, a two-phase alternating power-on mode is adopted; During steady-state high-speed operation, a duty cycle limited PWM control mode is adopted, and SVPWM technology is used to control the three-phase output; During disturbances / acceleration / deceleration, a full FOC closed-loop control mode is adopted.

2. The three-phase motor low-power drive control method based on state perception and multi-mode switching as described in claim 1, characterized in that: In step 1), the following is preset: Speed ​​threshold , ,and > Current threshold , ,and > Electromagnetic torque change rate threshold Threshold for rate of change of rotational speed ; The conditions for determining the motor's operating status are as follows: Standby / light load status determination: and ; Maintenance status determination: and ; Steady-state high-speed operation status determination: and ; Disturbance / acceleration / deceleration state determination: or ; in: This refers to the real-time speed of the motor. This represents the root mean square value of the three-phase current. The rate of change of electromagnetic torque; This represents the rate of change of rotational speed.

3. The three-phase motor low-power drive control method based on state perception and multi-mode switching as described in claim 2, characterized in that: The disturbance / acceleration / deceleration state determination has a higher priority than the other three states. That is, when the motor operating state meets the disturbance / acceleration / deceleration state determination conditions, it is forcibly switched to the full FOC closed-loop control mode.

4. The three-phase motor low-power drive control method based on state perception and multi-mode switching as described in claim 3, characterized in that: The standby / light load state, steady-state high-speed operation state, and steady-state high-speed operation state can all have hysteresis intervals and mode hold time thresholds set; the disturbance / acceleration / deceleration state can have mode hold time thresholds set.

5. The three-phase motor low-power drive control method based on state perception and multi-mode switching as described in claim 1, characterized in that: The single-phase alternating energizing mode means that only one of the U, V, or W phases is energized at any given time; the energizing sequence is determined by the rotor electrical angle partitioning, which can be achieved by using a lookup table method or an angle determination method.

6. The three-phase motor low-power drive control method based on state perception and multi-mode switching as described in claim 1, characterized in that: The dual-phase alternating energizing mode is to simultaneously conduct two phases to form a more continuous magnetic field; the electrical angle space is divided into multiple sectors, and torque is generated in each sector through the conduction of two-phase windings; a transition interval is set at the sector boundary so that the two-phase conduction control of adjacent sectors overlaps to a certain extent.

7. The three-phase motor low-power drive control method based on state perception and multi-mode switching as described in claim 1, characterized in that: The duty cycle limited PWM control mode uses dynamic adjustment of the duty cycle or limiting of the output voltage amplitude to limit the output voltage value.

8. A low-power drive control system for a three-phase motor based on state perception and multi-mode switching, characterized in that: include: Status recognition module: used to monitor the motor's operating status in real time and classify the current motor operating status according to preset criteria; Mode selection module: Embedded state machine or decision tree structure, it uses the output of the state recognition module as the input signal to perform control mode matching for the current working state of the motor; Multiple drive strategy modules: used to store different motor control logic; Motor control module: Used to control the on / off power supply of the three phases of the motor; The mode selection module can trigger the corresponding drive strategy module through mutual exclusion scheduling logic, and the motor control module controls the drive of the three-phase motor according to the retrieved control logic.

9. The three-phase motor low-power drive control system based on state perception and multi-mode switching as described in claim 8, characterized in that: The states identification module is categorized into standby / light load states, steady-state high-speed operation states, and disturbance / acceleration / deceleration states. The drive strategy module includes single-phase alternating power-on strategy, two-phase alternating power-on strategy, duty cycle limited PWM control strategy, and full FOC closed-loop control strategy, with each strategy corresponding to the other.

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