阅读说明：本技术 空压机无位置控制破冰启动方法及系统 (Air compressor no-position control ice-breaking starting method and system ) 是由 植万湖 熊礼勇 罗梦 余志春 于 2020-06-29 设计创作，主要内容包括：本发明公开了一种空压机无位置控制破冰启动方法及系统,方法包括：在给定转速命令值下,采用开环控制根据设定的翻转逻辑控制电机转子做正反转,开始破除冰；随着冰被破除,电机转子做正反转的实时转速发生变化,开环控制给定电机的电压处于变化状态；检测电机的三相电流,当一段时间内电压恒定时,通过电机电压方程计算在这段时间里电机转子的实时转速；将实时转速与给定的转速命令值进行比对,当差值在允许范围内则判定为破冰成功,否则判定未破冰成功。采用本发明电机控制方法及系统,使得空压机在极寒天气,冰冻住的条件下能够有效地完成破冰任务,并能通过自检的方式判断破冰成功与否并进行反馈是否进行下一步正常启动工作。(The invention discloses a method and a system for starting an air compressor without position control for ice breaking, wherein the method comprises the following steps: under a given rotating speed command value, controlling a motor rotor to rotate positively and negatively by adopting open-loop control according to set overturning logic, and starting to break and remove ice; the real-time rotating speed of the motor rotor rotating forward and backward changes along with the ice being broken, and the voltage of the given motor is controlled to be in a changing state by open loop; detecting three-phase current of the motor, and calculating the real-time rotating speed of a motor rotor in a period of time through a motor voltage equation when the voltage is constant in the period of time; and comparing the real-time rotating speed with a given rotating speed command value, judging that the ice breaking is successful when the difference value is within an allowable range, and otherwise, judging that the ice breaking is not successful. By adopting the motor control method and the motor control system, the air compressor can effectively complete the ice breaking task under the condition of extremely cold weather and frozen ice, and can judge whether the ice breaking is successful or not in a self-checking mode and feed back whether the next normal starting work is carried out or not.)

1. A method for starting an air compressor without position control for ice breaking is characterized by comprising the following steps:

under a given rotating speed command value, controlling a motor rotor to rotate positively and negatively by adopting open-loop control according to set overturning logic, and starting to break and remove ice;

the real-time rotating speed of the motor rotor rotating forward and backward changes along with the ice being broken, and the real-time voltage of the open-loop control changes immediately, so that the voltage of the motor given by the open-loop control is in a changing state;

detecting three-phase current of the motor, and calculating the real-time rotating speed of a motor rotor in a period of time through a motor voltage equation when the voltage is constant in the period of time;

and comparing the real-time rotating speed with the given rotating speed command value, judging that the ice breaking is successful when the difference value is within an allowable range, and otherwise, judging that the ice breaking is not successful.

2. The air compressor no-position control ice-breaking starting method as claimed in claim 1, further comprising the steps of: the voltage drop compensation for a given motor voltage is performed in advance in the open loop control.

3. The air compressor no-position control ice-breaking starting method as claimed in claim 1, wherein the flipping logic is: the time of each rotation is T1, and the time of each rotation is the time of the previous rotation plus a period of T2.

4. The air compressor no-position control ice-breaking starting method as claimed in claim 3, wherein the electronic rotor is set to rotate in forward and reverse directions n times, and in the time range t (3n-2) to t (3n-3) of the last rotation, the given stator voltage Us is controlled to be constant by open loop, and the corresponding rotating speed command value is constant; and is

In the time range t (3n-2) to t (3n-3), the real-time rotating speed of the motor rotor is calculated through a stator voltage mathematical model of the permanent magnet synchronous motor, and the rotor position is calculated through a derivation voltage equation:

θ＝arctan(A/B)

wherein A ═ u_α-Ri_α-L_dpi_α+ω_ei_β(L_q-L_d)

B＝-u_β+Ri_β+L_dpi_β+ω_ei_α(L_q-L_d)

In the formula u_α、u_βRespectively representing the stator voltage components of α and β, R is the equivalent resistance of the motor stator, i_α、i_βRepresenting the stator current components at α, β, respectively, p representing the differential, ω_eIndicating the electrical angular velocity, L, of the motor_d、L_qRepresenting d and q axis inductances, respectively.

5. The air compressor no-position control ice-breaking starting method as claimed in claim 4, wherein after the rotor position is obtained, a phase-locked loop is added after the rotor position to obtain a smooth rotation speed, and the obtained smooth rotation speed is compared with the rotation speed command value.

6. The utility model provides an air compressor machine does not have position control start-up system that opens ice which characterized in that: the system comprises a turnover logic module, an open-loop control module, a PWM (pulse-width modulation) module, an inverter and a rotating speed self-checking module, wherein a given rotating speed command value is input to the open-loop control module after passing through the turnover logic module; the rotating speed self-checking module is used for detecting the three-phase current of the motor, calculating the real-time rotating speed of the motor rotor in a period of time through a motor voltage equation when the voltage is constant in the period of time, comparing the real-time rotating speed with the given rotating speed command value, judging that ice breaking is successful when the difference value is within an allowable range, and otherwise, judging that ice breaking is not successful.

7. The air compressor no-position control ice-breaking starting system as claimed in claim 6, further comprising a pressure drop compensation module, wherein the given rotation speed command value is compensated for pressure drop by the pressure drop compensation module in advance before being input to the open loop control module.

8. The air compressor no-position control ice-breaking starting system as claimed in claim 6, wherein a turn logic is set in the turn logic module, the open-loop control module controls the motor rotor to rotate forward and backward according to the set turn logic, and the turn logic is: the time of each rotation is T1, and the time of each rotation is the time of the previous rotation plus a period of T2.

9. The air compressor no-position control ice-breaking starting system as claimed in claim 6, wherein the PWM modulation module adopts SVPWM modulation, and the inverter adopts a three-phase inverter.

Technical Field

The invention relates to the technical field of air compressor control, in particular to a method and a system for starting an air compressor without position control for ice breaking.

Background

The air compressor for the fuel cell vehicle can provide high-pressure air for the cathode reaction of the fuel cell, and provides clean air with required pressure and flow for the fuel cell according to the power requirement, and the performance of the air compressor directly influences the performance of a fuel cell system. A typical fuel cell air supply system is comprised of an air filter, an air compressor, an electric motor, an intercooler, a humidifier, an expander, and the like. The air compressor is of great importance to the fuel cell vehicle, the motor plays a more important role in the air compressor, and the high-rotating-speed motor is generally adopted to be directly driven to be connected with the impeller, so that the energy consumption of the air compressor can be effectively reduced. High speed motors are expensive due to the high precision and high resolution position/speed sensors, and their performance is affected in harsh environments such as extreme high speed, high temperature, and humidity. The speed sensorless control technology is mainly based on the existing motor parameters and the measured stator terminal voltage or current, and uses some specific algorithms to obtain the position and rotation speed of the motor.

Because the air compressor can work in various extreme weathers, the problem of how to start the motor rotor in the air compressor under the condition that the motor rotor is frozen in the extreme cold weather needs to be considered, based on the consideration, the invention designs the air compressor no-position control ice-breaking starting system, and the method has important engineering application value for the smooth starting of the motor.

Disclosure of Invention

In order to solve the defects existing in the prior art or potential defects, the invention provides the method and the system for starting the air compressor without position control for ice breaking, which can effectively complete the ice breaking task under the condition that the air compressor is frozen.

The technical scheme adopted by the invention is as follows: a method for starting an air compressor without position control for ice breaking comprises the following steps:

under a given rotating speed command value, controlling a motor rotor to rotate positively and negatively by adopting open-loop control according to set overturning logic, and starting to break and remove ice;

the real-time rotating speed of the motor rotor rotating forward and backward changes along with the ice being broken, and the real-time voltage of the open-loop control changes immediately, so that the voltage of the motor given by the open-loop control is in a changing state;

detecting three-phase current of the motor, and calculating the real-time rotating speed of a motor rotor in a period of time through a motor voltage equation when the voltage is constant in the period of time;

and comparing the real-time rotating speed with the given rotating speed command value, judging that the ice breaking is successful when the difference value is within an allowable range, and otherwise, judging that the ice breaking is not successful.

By adopting the air compressor no-position control ice-breaking starting method, the air compressor can effectively complete an ice-breaking task under the conditions of extreme cold weather and frozen ice, and can judge whether ice-breaking is successful or not in a self-checking mode and feed back whether the next normal starting work is carried out or not.

The air compressor no-position control ice-breaking starting method is further improved in that the method further comprises the following steps: the voltage drop compensation for a given motor voltage is performed in advance in the open loop control.

The air compressor no-position control ice-breaking starting method is further improved in that the overturning logic is as follows: the time of each rotation is T1, and the time of each rotation is the time of the previous rotation plus a period of T2.

The method for starting the air compressor without position control for ice breaking is further improved in that the electronic rotor is set to rotate positively and negatively for n times, the given stator voltage Us is controlled to be constant in an open loop within the time range t (3n-2) to t (3n-3) of the last rotation, and the corresponding rotating speed command value is constant; and is

In the time range t (3n-2) to t (3n-3), the real-time rotating speed of the motor rotor is calculated through a stator voltage mathematical model of the permanent magnet synchronous motor, and the rotor position is calculated through a derivation voltage equation:

θ＝arctan(A/B)

wherein the content of the first and second substances,

A＝u_α-Ri_α-L_dpi_α+ω_ei_β(L_q-L_d)

B＝-u_β+Ri_β+L_dpi_β+ω_ei_α(L_q-L_d)

in the formula u_α、u_βRespectively representing the stator voltage components of α and β, R is the equivalent resistance of the motor stator, i_α、i_βRepresenting the stator current components at α, β, respectively, p representing the differential, ω_eIndicating the electrical angular velocity, L, of the motor_d、L_qRepresenting d and q axis inductances, respectively.

The method for starting the air compressor without position control for ice breaking is further improved in that after the rotor position is obtained, a phase-locked loop is added after the rotor position to obtain a smooth rotating speed, and the obtained smooth rotating speed is compared with the rotating speed command value.

A no-position control ice-breaking starting system of an air compressor comprises a turnover logic module, an open-loop control module, a PWM (pulse-width modulation) module, an inverter and a rotating speed self-checking module, wherein a given rotating speed command value is input to the open-loop control module after passing through the turnover logic module; the rotating speed self-checking module is used for detecting the three-phase current of the motor, calculating the real-time rotating speed of the motor rotor in a period of time through a motor voltage equation when the voltage is constant in the period of time, comparing the real-time rotating speed with the given rotating speed command value, judging that ice breaking is successful when the difference value is within an allowable range, and otherwise, judging that ice breaking is not successful.

The air compressor no-position control ice-breaking starting system is further improved by comprising a pressure drop compensation module, wherein the given rotating speed command value is subjected to pressure drop compensation in advance through the pressure drop compensation module before being input into the open-loop control module.

The air compressor no-position control ice-breaking starting system is further improved in that a turning logic is set in the turning logic module, the open-loop control module controls the motor rotor to rotate positively and negatively according to the set turning logic, and the turning logic is as follows: the time of each rotation is T1, and the time of each rotation is the time of the previous rotation plus a period of T2.

The air compressor non-position control ice-breaking starting system is further improved in that the PWM module adopts SVPWM, and the inverter adopts a three-phase inverter.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is an architecture diagram of a non-position control ice-breaking starting system of an air compressor in an embodiment of the invention.

Fig. 2 is a graph of open-loop given voltage before and after compensation of pressure drop in the method for starting the air compressor without position control for ice breaking according to the embodiment of the invention.

Fig. 3 is a timing diagram of an ice breaking strategy of the air compressor non-position control ice breaking starting method according to the embodiment of the invention.

Fig. 4 is a block diagram of the rotation speed calculation using the phase locked loop PLL according to the embodiment of the present invention.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

The embodiments of the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

In order to enable the frozen motor rotor in extremely cold weather to be capable of breaking ice before normal rotating speed closed-loop control, a certain strategy is required to be added to quickly break the ice. In order to rapidly break ice, the strategy of the motor control addition is to control the forward and reverse rotation of the motor through logic overturning on the basis of open loop control, the amplitude of forward and reverse swing is larger and larger on the basis of the actual situation, and finally the rotating speed of the motor is maintained within a certain range after a certain time of detection, so that the ice breaking is considered to be successful, and the next stage of normal starting work can be carried out.

Based on this, the key research of the invention is that the air compressor is started without position ice breaking, so the ice breaking strategy and the open-loop position-free control algorithm are mainly explained, and the duty ratio part generated by PWM modulation is not specifically explained (the related technology is the prior art). Open-loop position-free control is a scalar control mode based on a motor steady-state model, and aims to keep the stator flux linkage constant, so that the maximum torque current ratio and the fastest torque response can be obtained.

Referring to fig. 1, which is an architecture diagram of a no-position control ice-breaking starting system of an air compressor according to an embodiment of the present invention, as shown in the figure, the no-position control ice-breaking starting system of the air compressor mainly includes a flipping logic module 11, an open loop control module 12, a PWM modulation module 13, an inverter 14, a rotation speed self-checking module 16, and further may further include a voltage drop compensation module 15, and a motor adopts a permanent magnet synchronous motor PMSM.

The inverter 14 preferably adopts a three-phase inverter, the PWM modulation module 13 preferably adopts an SVPWM modulation method, the three-phase inverter adopts SVPWM control, SVPWM is short for Space Vector Pulse Width Modulation (SVPWM), the SVPWM modulation method is based on the ideal magnetic flux circle of the alternating current motor when three-phase symmetrical sine wave voltage is supplied, the actual magnetic flux generated by different switching modes of the inverter is used to approach the reference magnetic flux circle, and the switching state of the inverter is determined by the comparison result to form a PWM waveform, in view of the motor, how to make the motor obtain a circular rotating magnetic field with constant amplitude.

The open-loop control module 12 may be an open-loop control circuit, and under the open-loop control, the problem of system stability is very important, in order to meet the use requirement of the motor under the low-frequency condition, and to ensure smooth start under the condition of load, the voltage drop compensation module 15 is adopted to perform the voltage drop compensation operation when the given voltage needs to compensate the resistance drop in the open-loop control. The open-loop control characteristics of the permanent magnet synchronous motor before and after compensation are respectively shown as linear relations in fig. 2, wherein a curve I represents an open-loop given voltage curve before voltage drop compensation, a curve II represents an open-loop given voltage curve after voltage drop compensation, and in the graph, U₀Is the initial stator voltage after compensation of the voltage drop, U_1NIs f_1NCorresponding stator voltage at frequency, Us being stator voltage, f₁Is the stator frequency of the motor, f_1NIs the motor target stator frequency.

The turning logic module 11 is set with a turning logic, the open-loop control module controls the motor rotor to rotate positively and negatively according to the set turning logic, and the ice is broken and removed, and the set turning logic is preferably: the time of each rotation is T1, and the time of each rotation is the time of the previous rotation plus a period of T2.

Specifically, assuming that the electronic rotor needs to turn over n (odd) times to complete ice breaking, each time the electronic rotor rotates once, in order to slowly clear the voltage command value, so as to prevent overcurrent, the electronic rotor stays for a short time T1 after the forward rotation or the reverse rotation is finished, and the staying interval T1 is as shown in fig. 3 below:

T1＝t2-t1＝t5-t4＝t8-t7＝…

in order to break the ice more quickly, the method of the present invention adds a strategy of increasing the amplitude of the forward and reverse rotation, corresponding to an increasing time of the forward and reverse rotation, and increasing the time T2 for each rotation, as shown in fig. 3, wherein:

T2＝t4-t3＝t7-t6＝…

after repeating the forward and reverse rotation for n times, whether ice breaking is successful or not needs to be detected, and the specific operation is as follows:

1. when setting positive and negative rotation for n times, ensuring that the last rotation is within the time range from t (3n-2) to t (3n-3), and controlling the given stator voltage Us to be constant by open loop and the corresponding rotating speed command value to be constant;

2. in the period from t (3n-2) to t (3n-3), the rotating speed of the motor is estimated by a direct calculation method through a stator voltage mathematical model of the permanent magnet synchronous motor, and the position of the rotor can be directly calculated by equivalent voltage and current through deducing a voltage equation, wherein the method comprises the following steps:

θ＝arctan(A/B)

wherein the content of the first and second substances,

A＝u_α-Ri_α-L_dpi_α+ω_ei_β(L_q-L_d)

B＝-u_β+Ri_β+L_dpi_β+ω_ei_α(L_q-L_d)

in the formula u_α、u_βRespectively representing the stator voltage components of α and β, R is the equivalent resistance of the motor stator, i_α、i_βRepresenting the stator current components at α, β, respectively, p representing the differential, ω_eIndicating the electrical angular velocity, L, of the motor_d、L_qRepresenting d and q axis inductances, respectively.

A, B has no specific physical meaning, and other quantities in the above formula can be considered known, and A and B are calculated by the above quantities, and then the motor rotor position is obtained by performing the inverse tangent arctan on (A/B).

The position of the motor rotor is estimated through the open Loop, in order to obtain a smooth estimated rotating speed, a Phase Locked Loop (PLL for short) can be added behind the estimated rotor position to obtain the estimated rotating speed, the estimated rotating speed is compared with a rotating speed command value, the ice breaking is considered to be successful if the estimated rotating speed is within a certain small range, and if the estimated rotating speed is beyond the certain small range, the ice breaking is judged to be unsuccessful. The phase-locked loop PLL is a prior art, and is a kind of PLLA negative feedback control system for tuning a voltage controlled oscillator to generate a target frequency by using a voltage generated by phase synchronization, wherein the corresponding symbols in fig. 4 mean: θ is a position obtained by arc tangent, θ is a position fed back, PI represents PI control (linear control), ω is_rRepresenting the electrical angular velocity of the motor, 1/s represents the integral.

The structure of the whole air compressor non-position control ice-breaking starting system in the embodiment of the invention is shown in fig. 1:

a given speed command value f_{Given a}After passing through a turnover logic module 11 and a voltage drop compensation module 15 respectively, inputting the voltage V after set turnover logic and voltage drop compensation into an open-loop control module 12, distributing the voltage V to the components of motor stator voltages at α and β through the open-loop control link, estimating the rotation speed of the motor by a direct calculation method through a mathematical model of the stator voltages of the permanent magnet synchronous motor according to the components of the given stator voltages at α and β, and directly calculating the equivalent of the voltage and the current to obtain the rotor position through deducing a voltage equation_u、i_v、i_w(three-phase Current i of Motor_u、i_v、i_wAfter coordinate transformation by Clarke (Clarke), i_α、i_βThe voltage is input into a rotating speed self-checking module), when the voltage is constant in a period of time, the corresponding rotating speed is constant, and the real-time rotating speed of the motor rotor in the period of time is calculated through a motor voltage equation; real-time rotating speed and given rotating speed command value f_{Given a}Or open-loop control is performed on the given motor voltage for comparison, and when the difference value is within an allowable range, the ice breaking is judged to be successful, otherwise, the ice breaking is judged not to be successful.

By adopting the method and the system for starting the air compressor without position control for ice breaking, the air compressor can effectively complete the task of ice breaking under the conditions of extreme cold weather and frozen ice, and can judge whether the ice breaking is successful or not in a self-checking mode and feed back whether the next normal starting work is carried out or not.

It should be noted that the structures, ratios, sizes, and the like shown in the drawings attached to the present specification are only used for matching the disclosure of the present specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions of the present invention, so that the present invention has no technical essence, and any structural modification, ratio relationship change, or size adjustment should still fall within the scope of the technical content of the present disclosure without affecting the efficacy and the achievable purpose of the present invention. In addition, the terms "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not to be construed as a scope of the present invention.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

The techniques, shapes, and configurations not described in detail in the present invention are all known techniques.