阅读说明：本技术 永磁同步电机无电解电容驱动器电压边界优化过调制方法 (Voltage boundary optimization overmodulation method for permanent magnet synchronous motor electrolytic capacitor-free driver ) 是由 王高林 胡海明 丁大尉 赵楠楠 张国强 徐殿国 于 2019-11-04 设计创作，主要内容包括：一种永磁同步电机无电解电容驱动器电压边界优化过调制方法,属于电机控制技术领域。本发明针对现有永磁同步电机无电解电容电机驱动系统在电机运行至过调制区域时,会出现输出电压矢量相位跳变和退回的问题。包括采集三相无电解电容驱动器的实际三相电流并进行处理,获得α轴电压指令u<Sub>α</Sub><Sup>*</Sup>和β轴电压指令u<Sub>β</Sub><Sup>*</Sup>；再进一步计算第一预期作用时间T<Sub>i_a</Sub>、T<Sub>i+1_a</Sub>和第二预期作用时间T<Sub>i_f</Sub>、T<Sub>i+1_f</Sub>；再与采样周期T<Sub>s</Sub>对比,获得判断结果；根据判断结果计算T<Sub>i</Sub>和T<Sub>i+1</Sub>；采用脉冲信号运算单元基于T<Sub>i</Sub>和T<Sub>i+1</Sub>进行运算,获得脉冲信号P1,所述脉冲信号P1经过三相无电解电容驱动器对永磁同步电机进行驱动。本发明能够更好的保障逆变系统直流侧的电压利用率。(The invention relates to a voltage boundary optimization over-modulation method for a non-electrolytic capacitor driver of a permanent magnet synchronous motor, belonging to the technical field of motor control and aiming at the problems that the output voltage vector phase jumps and returns when the motor runs to an over-modulation region in the existing non-electrolytic capacitor motor driving system of the permanent magnet synchronous motor α * And β Axis Voltage instruction u β * (ii) a The first expected action time T is further calculated i_a 、T i+1_a And a second expected time of action T i_f 、T i+1_f (ii) a And then with the sampling period T s Comparing to obtain a judgment result; calculating T according to the judgment result i And T i+1 (ii) a By usingThe pulse signal operation unit is based on T i And T i+1 And performing operation to obtain a pulse signal P1, wherein the pulse signal P1 drives the permanent magnet synchronous motor through a three-phase non-electrolytic capacitor driver. The invention can better ensure the voltage utilization rate of the direct current side of the inverter system.)

1. A voltage boundary optimization overmodulation method of a permanent magnet synchronous motor driver without electrolytic capacitors is characterized by comprising the following steps:

collecting and processing actual three-phase current of a three-phase electrolytic-capacitor-free driver to obtain α shaft voltage instruction u _α ^*And β Axis Voltage instruction u _β ^*；

Step two, adopting a first basic voltage vector action time arithmetic unit (201) to carry out a α axis voltage instruction u _α ^*β Axis Voltage instruction u _β ^*And actual voltage U output by three-phase electrolytic capacitor-free driver _dcCalculating to obtain a first expected action time T of two adjacent basic voltage vectors in the vector control of the permanent magnet synchronous motor _{i_a}、T _{i+1_a}The α axis voltage instruction u is simultaneously operated by a second basic voltage vector action time operation unit (202) _α ^*β Axis Voltage instruction u _β ^*And a predetermined fixed voltage U of a three-phase electrolytic capacitor-free driver _fixedCalculating to obtain a second expected action time T of two adjacent basic voltage vectors in the vector control of the permanent magnet synchronous motor _{i_f}、T _{i+1_f}；

Step three: the condition judging unit (203) judges the condition according to T _{i_a}、T _{i+1_a}And T _{i_f}、T _{i+1_f}And a sampling period T _sObtaining a judgment result according to the comparison relationship;

step four: calculating to obtain a calculated value T of the action time of two adjacent basic voltage vectors according to the judgment result of the step three _iAnd T _i+1；

Step five: based on T by adopting a pulse signal operation unit (207) _iAnd T _i+1And performing operation to obtain a pulse signal P1, wherein the pulse signal P1 drives the permanent magnet synchronous motor through a three-phase non-electrolytic capacitor driver.

2. The voltage boundary optimization overmodulation method for the permanent magnet synchronous motor electrolytic capacitor-free driver according to claim 1, wherein the determination result in the third step comprises:

will T _{i_a}+T _{i+1_a}≤T _sAs condition 1;

will T _{i_a}+T _{i+1_a}>T _s&T _{i_f}/2+T _{i+1_f}≤T _s&T _{i_f}+T _{i+1_f}/2≤T _sAs condition 2;

will T _{i_f}+T _{i+1_f}/2>T _sor T _{i_f}/2+T _{i+1_f}>T _sAs condition 3.

3. The voltage boundary optimization overmodulation method for the PMSM capacitor-less driver according to claim 2, wherein in the fourth step, a calculation value T for obtaining action time of two adjacent basic voltage vectors is calculated according to the judgment result of the third step _iAnd T _i+1The method comprises the following steps:

when the judgment result output by the condition judgment unit (203) is a condition 1, a third basic voltage vector acting time operation unit (204) is adopted to calculate and obtain a calculation value T of two adjacent basic voltage vector acting times _iAnd T _i+1；

When the judgment result output by the condition judgment unit (203) is a condition 2, a calculation value T for calculating and obtaining the action time of two adjacent basic voltage vectors is calculated by adopting a fourth basic voltage vector action time operation unit (205) _iAnd T _i+1；

When the judgment result output by the condition judgment unit (203) is a condition 3, a calculation value T for calculating and obtaining the action time of two adjacent basic voltage vectors is calculated by adopting a No. five basic voltage vector action time operation unit (206) _iAnd T _i+1。

4. The PMSM electrolytic capacitor-free drive voltage boundary optimization overmodulation method according to any of claims 1-3, wherein α axis voltage command u obtained in the first step _α ^*And β Axis Voltage instruction u _β ^*Implemented based on a vector control unit comprising:

a first subtraction unit (101), a speed regulator (102), a first multiplication unit (103), a second subtraction unit (104), a second multiplication unit (105), a third subtraction unit (106), a current regulator (107), a two-phase rotation coordinate to two-phase static coordinate conversion unit (108), an encoder (112), a Clarke conversion unit (113), a Park conversion unit (114) and a rotating speed position calculation unit (115),

a Clarke conversion unit (113) couples the actual three-phase current i in the step one _a、i _b、i _cThe conversion is carried out to obtain the actual α shaft current i _αAnd actual β axis current i _βThe Park conversion unit (114) compares the actual α axis current i _αAnd actual β axis current i _βThe actual d-axis current i is obtained through conversion _dAnd the actual q-axis current i _q；

The encoder (112) collects the displacement signal of the permanent magnet synchronous motor and performsAfter treatment, the actual rotating speed omega of the motor is obtained _eThe rotation speed position calculation unit (115) calculates the actual rotation speed omega of the motor _eProcessed to obtain the electrical angle theta of the motor _e；

A first subtraction unit (101) for giving a rotational speed command omega _e ^*With the actual speed omega of the motor _eDifferencing to obtain a difference in rotational speed Δ ω _eDifference in rotational speed Δ ω _eObtaining a current command i through a speed regulator (102) _srefCommand of current i _srefThe cosine value cos theta of the current command angle theta is calculated by a first multiplication unit (103) to obtain a d-axis current command i _d ^*Command of current i _srefThe sine value sin theta of the angle theta of the current instruction is calculated by a second multiplication unit (105) to obtain a q-axis current instruction i _q ^*D-axis Current command i _d ^*And the actual d-axis current i _dD-axis current difference delta i is calculated by a second subtraction unit (104) _dQ-axis current command i _q ^*With actual q-axis current i _qThe q-axis current difference delta i is obtained by calculation through a third subtraction unit (106) _qD-axis current difference Δ i _dCurrent difference Δ i from q axis _qD-axis voltage command u is calculated through a current regulator (107) _d ^*And q-axis voltage command u _q ^*D-axis voltage command u _d ^*Q-axis voltage command u _q ^*And electrical angle theta of the motor _eα axis voltage command u is obtained by a two-phase rotation coordinate to two-phase static coordinate conversion unit (108) _α ^*And β Axis Voltage instruction u _β ^*。

Technical Field

The invention relates to an electrolytic capacitor-free driver voltage boundary optimization overmodulation method for a permanent magnet synchronous motor, and belongs to the technical field of motor control.

Background

The permanent magnet synchronous motor has the advantages of high power density, high torque density and low cost, and has more and more applications in the fields of industry and household appliances. In a traditional motor driving topology, a large-capacitance electrolytic capacitor is used on a direct current side of the traditional motor driving topology to ensure the stability of direct current bus voltage, but the service life of the electrolytic capacitor is greatly influenced by environmental temperature and current ripple. The thin-film capacitor can obviously prolong the service life and reliability of the motor driving system, and the electrolytic capacitor at the direct current side is replaced by the thin-film capacitor, so that the motor driving system without the electrolytic capacitor is called as a motor driving system without the electrolytic capacitor.

The motor driving system without electrolytic capacitor for permanent magnet synchronous motor is mainly composed of a diode uncontrolled rectifier bridge, a small-capacitance value film capacitor, a three-phase voltage inverter and a permanent magnet synchronous motor. In order to improve the voltage utilization rate on the direct current side, when the motor operates in an overmodulation region with a high modulation ratio, even jump and retreat of the output voltage vector phase may occur due to contraction and expansion of the hexagonal voltage boundary caused by fluctuation of 6 times of the grid frequency, resulting in a large motor voltage THD (total harmonic distortion) and torque ripple. Therefore, the overmodulation research of improving the utilization rate of the bus voltage of the motor driving system without the electrolytic capacitor has important significance.

Disclosure of Invention

The invention provides a voltage boundary optimization over-modulation method for a non-electrolytic capacitor driver of a permanent magnet synchronous motor, aiming at the problem that the phase jump and the return of an output voltage vector can occur when the motor runs to an over-modulation region in the existing non-electrolytic capacitor motor driving system of the permanent magnet synchronous motor.

The invention discloses a voltage boundary optimization overmodulation method for a permanent magnet synchronous motor driver without electrolytic capacitor, which comprises the following steps:

collecting and processing actual three-phase current of a three-phase electrolytic-capacitor-free driver to obtain α shaft voltage instruction u _α ^*And β Axis Voltage instruction u _β ^*；

Step two, adopting a first basic voltage vector action time arithmetic unit to carry out the α axis voltage instruction u _α ^*β Axis Voltage instruction u _β ^*And actual voltage U output by three-phase electrolytic capacitor-free driver _dcCalculating to obtain a first expected action time T of two adjacent basic voltage vectors in the vector control of the permanent magnet synchronous motor _{i_a}、T _{i+1_a}Simultaneously, the α shaft voltage instruction u is acted by the second basic voltage vector action time arithmetic unit _α ^*β Axis Voltage instruction u _β ^*And a predetermined fixed voltage U of a three-phase electrolytic capacitor-free driver _fixedCalculating to obtain a second expected action time T of two adjacent basic voltage vectors in the vector control of the permanent magnet synchronous motor _{i_f}、T _{i+1_f}；

Step three: the condition judging unit is based on T _{i_a}、T _{i+1_a}And T _{i_f}、T _{i+1_f}And a sampling period T _sObtaining a judgment result according to the comparison relationship;

step four: calculating to obtain a calculated value T of the action time of two adjacent basic voltage vectors according to the judgment result of the step three _iAnd T _i+1；

Step five: based on T by adopting pulse signal operation unit _iAnd T _i+1And performing operation to obtain a pulse signal P1, wherein the pulse signal P1 drives the permanent magnet synchronous motor through a three-phase non-electrolytic capacitor driver.

According to the voltage boundary optimization overmodulation method of the permanent magnet synchronous motor electrolytic capacitor-free driver, the judgment result of the third step comprises the following steps:

will T _{i_a}+T _{i+1_a}≤T _sAs condition 1;

will T _{i_a}+T _{i+1_a}>T _s&T _{i_f}/2+T _{i+1_f}≤T _s&T _{i_f}+T _{i+1_f}/2≤T _sAs condition 2;

will T _{i_f}+T _{i+1_f}/2>T _sor T _{i_f}/2+T _{i+1_f}>T _sAs condition 3.

According to the voltage boundary optimization overmodulation method of the permanent magnet synchronous motor electrolytic capacitor-free driver, in the fourth step, a calculation value T of action time of two adjacent basic voltage vectors is calculated and obtained according to a judgment result of the third step _iAnd T _i+1The method comprises the following steps:

when the judgment result output by the condition judgment unit is a condition 1, the calculation value T of the action time of two adjacent basic voltage vectors is calculated and obtained by adopting the third basic voltage vector action time operation unit _iAnd T _i+1；

When the judgment result output by the condition judgment unit is a condition 2, the calculation value T of the action time of two adjacent basic voltage vectors is calculated and obtained by adopting the fourth basic voltage vector action time operation unit _iAnd T _i+1；

When the judgment result output by the condition judgment unit is a condition 3, a calculation value T of the action time of two adjacent basic voltage vectors is calculated and obtained by adopting a fifth basic voltage vector action time operation unit _iAnd T _i+1。

According to the voltage boundary optimization overmodulation method of the permanent magnet synchronous motor electrolytic capacitor-free driver, α shaft voltage instruction u obtained in the step one _α ^*And β Axis Voltage instruction u _β ^*Implemented based on a vector control unit comprising:

a first subtraction unit, a speed regulator, a first multiplication unit, a second subtraction unit, a second multiplication unit, a third subtraction unit, a current regulator, a two-phase rotating coordinate to two-phase static coordinate conversion unit, an encoder, a Clarke conversion unit, a Park conversion unit and a rotating speed position calculation unit,

the Clarke conversion unit couples the actual three-phase current i in the step one _a、i _b、i _cThe conversion is carried out to obtain the actual α shaft current i _αAnd actual β axis current i _βPark transformation unit for actual α axis current i _αAnd actual β axis current i _βThe actual d-axis current i is obtained through conversion _dAnd the actual q-axis current i _q；

The encoder acquires and processes the displacement signal of the permanent magnet synchronous motor to obtain the actual rotating speed omega of the motor _eThe rotation speed position calculating unit calculates the actual rotation speed omega of the motor _eProcessed to obtain the electrical angle theta of the motor _e；

The first subtraction unit gives a rotation speed instruction omega _e ^*With the actual speed omega of the motor _eDifferencing to obtain a difference in rotational speed Δ ω _eDifference in rotational speed Δ ω _eObtaining a current instruction i through a speed regulator _srefCommand of current i _srefThe cosine value cos theta of the current instruction angle theta is calculated by a first multiplication unit to obtain a d-axis current instruction i _d ^*Command of current i _srefThe sine value sin theta of the angle theta of the current instruction is calculated by a second multiplication unit to obtain a q-axis current instruction i _q ^*D-axis Current command i _d ^*And the actual d-axis current i _dD-axis current difference delta i is calculated by a second subtraction unit _dQ-axis current command i _q ^*With actual q-axis current i _qThe q-axis current difference delta i is obtained through calculation of a third subtraction unit _qD-axis current difference Δ i _dCurrent difference Δ i from q axis _qD-axis voltage command u is obtained through calculation of a current regulator _d ^*And q-axis voltage command u _q ^*D-axis voltage command u _d ^*Q-axis voltage command u _q ^*And electrical angle theta of the motor _eα axis voltage command u is obtained by a conversion unit from two-phase rotating coordinates to two-phase static coordinates _α ^*And β Axis Voltage instruction u _β ^*。

The invention has the beneficial effects that: the invention provides an optimized voltage boundary overmodulation strategy based on a network side three-phase input electrolytic capacitor-free permanent magnet synchronous motor driving system when a motor runs to a high modulation overmodulation region. The invention obtains a pulse signal P1 for driving the permanent magnet synchronous motor based on a series of calculation of the actual three-phase current of the three-phase non-electrolytic capacitor driver and the displacement of the permanent magnet synchronous motor. Through the data processing process of the invention, the pulse signal P1 is adopted to control the motor, and the phenomena of jump, return and torque pulsation of the vector phase of the output voltage can be effectively avoided, so that the voltage utilization rate of the direct current side of the inverter system can be better ensured.

Drawings

FIG. 1 is a block flow diagram of a PMSM electrolytic capacitor-less driver voltage boundary optimization overmodulation method in accordance with the present invention;

FIG. 2 is a graph of output variable ripple for a PMSM in the overmodulation region without the method of the present invention; wherein T is _eIs electromagnetic torque, ω _rThe motor rotating speed;

FIG. 3 is a graph of output variable ripple of a PMSM in the overmodulation region when the method of the present invention is used;

FIG. 4 is a waveform diagram of output voltage vector phase jump and back-off of a PMSM in an overmodulation region without the method of the present invention; wherein theta is _uIs the angle of the output voltage vector, u _αIs α Axis Voltage, i _aActual A phase current;

fig. 5 is a waveform diagram of a voltage vector output by the pm synchronous machine in the overmodulation region when the method of the present invention is applied.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.