CN101770002A - Apparatus and method for monitoring demagnetization state of permanent magnet of permanent magnet motor - Google Patents

Abstract

The invention relates to the magnetic material detection field, in particular to an apparatus and a method for monitoring a demagnetization state of a permanent magnet of a permanent magnet motor. The apparatus for monitoring the demagnetization state of the permanent magnet of the permanent magnet motor comprises a battery (1), an inverter (2) and a permanent magnet motor (5), and is characterized by also comprising a U phase current sensor (31), a V phase current sensor (32), a speed sensor (6) and a microprocessor (7), a U phase line and a V phase line are respectively connected with a phase current sensor in series, the speed sensor (6) is connected on the permanent magnet motor (5) in parallel, and the U phase current sensor (31), the V phase current sensor (32) and the speed sensor (6) are all connected with the microprocessor (7) by leads. The invention can accurately and rapidly detect performances of the permanent magnet, and does not influence the control performances of the system.

Description

The demagnetized state supervising device and the method for permanent magnet of permanent magnet motor

Technical field

The present invention relates to magnetic material detection field, be specially a kind of demagnetized state supervising device and method of permanent magnet of permanent magnet motor.

Background technology

Motor generally is made of stator and rotor, and stator produces alternating magnetic field, thereby the magnetic line of force of rotor winding cutting stator alternating magnetic field induces induced electromotive force when rotor is driven by prime mover, and be generator this moment; Thereby the rotor winding is drawn by alternating magnetic field and rotates externally output torque when from rotor input electric energy, and be motor this moment.Alternating magnetic field on the stator, the past all adopts from the mode of external world's input exciting current and produces, and based on to the continuous lifting of energy-conservation requirement and the continuous application of high magnetic material, adopts the motor of permanent magnet to begin again to have obtained to use widely.But permanent magnet has the demagnetization characteristic, service time of a specified duration its magnetic can slowly disappear, especially the demagnetization phenomenon is especially obvious when high temperature and big electric current thereof, when serious even permanent demagnetization takes place.Requisite link when the magnetic field in the motor is the motor operate as normal is for motor, in case demagnetization has taken place, to cause external output torque sharply to reduce, the ratio that this moment, electric energy changed into mechanical energy also will reduce greatly, and will change into heat energy, thereby cause danger.Therefore the permanent magnet to magneto is very important as magnetic monitoring.But, the present supervising device that uses, with this magnetic of judging permanent magnet normally whether to adopt utilize temperature sensor measurement armature winding temperature and more, because the temperature of armature winding and the temperature of permanent magnet and inconsistent, so this way can not draw the accurate information of permanent magnet magnetic, and, in case permanent magnet demagnetizes, can not diagnose out permanent magnet whether to demagnetize by this temperature sensor.Therefore, existing detection method for supervising can not in time report to the police and handle, and can cause bigger potential safety hazard to system.

Summary of the invention

In order to overcome the defective of prior art, a kind of equipment that can monitor permanent magnet magnetic in real time is provided, the invention discloses a kind of demagnetized state supervising device and method of permanent magnet of permanent magnet motor.

The present invention reaches goal of the invention by following technical solution:

A kind of demagnetized state supervising device of permanent magnet of permanent magnet motor, comprise battery, inverter and magneto, battery is connected with inverter with lead, after changing three-phase alternating current into, the direct current that inverter is exported battery is connected with magneto with lead again, it is characterized in that: also comprise U phase current sensor, V phase current sensor, speed pickup and microprocessor, microprocessor has numerical operation, the PI conversion, data storing and information output function, connect in the three-phase conducting wire of inverter and motor, U phase line and V phase line are connected in series U phase current sensor and V phase current sensor respectively, on the magneto and connect a speed pickup, U phase current sensor, V phase current sensor all uses lead to be connected with microprocessor with speed pickup.

The demagnetized state supervising device of described permanent magnet of permanent magnet motor is characterized in that: microprocessor adopts the DSP microprocessor.

The demagnetized state supervising device of described permanent magnet of permanent magnet motor is characterized in that: microprocessor also is connected with vehicle-mounted LCDs, and when the microprocessor judges permanent magnet had obvious demagnetization, microprocessor was controlled the vehicle-mounted LCDs information that gives a warning.

A kind of demagnetized state method for supervising of permanent magnet of permanent magnet motor is undertaken by phase current and the angular velocity of rotation of measuring magneto when magneto is in the zero moment control model, it is characterized in that: carry out successively as follows:

Choose the U phase line and the V phase line respectively is connected in series U phase current sensor and V phase current sensor on lead from three-phase supply to magneto that supply with, establishing the U phase current that records is I _u, the V phase current is I _v

On magneto and connect an angular-rate sensor, establishing the motor angular velocity of rotation that records is ω, and the time of experiencing during measurement is t;

The U phase current I that U phase current sensor is recorded _u, the V phase current I that records of V phase current sensor _vThe motor angular velocity of rotation ω that records with angular-rate sensor and these five data of time t of experience all input to microprocessor, and do following the processing to draw electric current quadrature component I _qWith electric current longitudinal axis component I _d:

$\left[\begin{array}{c}{I}_d\\ I_q\end{array}\right]=\left[\begin{array}{cc}\cos \mathrm{\ωt}& \sin \mathrm{\ωt}\\ -\sin \mathrm{\ωt}& \cos \mathrm{\ωt}\end{array}\right]\×\left(\left[\begin{array}{cc}1& 0\\ \frac{1}{\sqrt{3}}& \frac{2}{\sqrt{3}}\end{array}\right]\left[\begin{array}{c}{I}_u\\ I_v\end{array}\right]\right)$

Calculate Id and the Iq data quadrature component V that draws voltage through the PI conversion of microprocessor _qLongitudinal axis component V _d, and be calculated as follows and draw motor stator phase voltage amplitude V _DqWith motor magnetic linkage λ:

$V_{\mathrm{dq}}=\sqrt{{\mathrm{<figure-callout\; id="2"\; label="v\; d"\; filenames="H2008102048828E0000011.png"\; state="\{\{state\}\}">v</figure-callout>}}_d^{}+{\mathrm{<figure-callout\; id="2"\; label="v\; q"\; filenames="H2008102048828E0000011.png"\; state="\{\{state\}\}">v</figure-callout>}}_q^{}},$ $\mathrm{\&lambda;}=\frac{v_{\mathrm{dq}}}{\mathrm{\&omega;}},$

If the ratings of magneto magnetic linkage is λ _Cal, when the λ value that records at (0.8 λ _Cal, 1.2 λ _Cal) interval in the time, microprocessor is judged the not obviously demagnetization of permanent magnet magnetic of magneto, when the λ value that records at (0,0.8 λ _Cal) interval in the time, microprocessor judges that magneto has tangible demagnetization phenomenon.

The invention has the beneficial effects as follows: by real-time measurement and the closely-related parameter of permanent magnet magnetic, judge permanent magnet magnetic normally whether, needn't increase extra-pay, adopt DSP microprocessor efficiently, can detect permanent magnet performance quickly and accurately, and, can not influence the control performance of system because this detection can be set in and carry out work in free time.

Description of drawings

Fig. 1 is a structural representation of the present invention.

Embodiment

Below further specify the present invention by specific embodiment.

Embodiment 1

A kind of demagnetized state supervising device of permanent magnet of permanent magnet motor, comprise battery 1, inverter 2, U phase current sensor 31, V phase current sensor 32, magneto 5, speed pickup 6 and microprocessor 7, as shown in Figure 1, concrete structure is: battery 1 usefulness lead is connected with inverter 2, be connected with magneto 5 with lead after the direct current that inverter 2 is exported battery changes three-phase alternating current into again, connect in the three-phase conducting wire of inverter 2 and motor 5, U phase line and V phase line are connected in series U phase current sensor 31 and V phase current sensor 32 respectively, on the magneto 5 and connect a speed pickup 6, U phase current sensor 31, V phase current sensor 32 all uses lead to be connected with microprocessor 7 with speed pickup 6, and microprocessor 7 has numerical operation, the PI conversion, data storing and information output function, microprocessor 7 adopts the DSP microprocessor.

In the hybrid-electric car operating condition, so-called zero moment control model is arranged; Be rotor with engine or power train rotation and the motor output torque is zero.When motor speed is lower than flex point, direct-axis component I _dWith quadrature axis component I _qSet-point all be zero, at this moment, have following formula to set up:

V _dq＝λω，

In the formula, V _DqBe motor stator phase voltage amplitude, λ is the motor magnetic linkage, and ω is the angular velocity of motor shaft.

The U phase current I that U phase current sensor 31 is recorded _u, the V phase current I that records of V phase current sensor 32 _vThe magneto 5 angular velocity of rotation ω that record with angular-rate sensor 6 and these five data of time t of experience all input to microprocessor 7, and do following the processing to draw the quadrature component I of electric current _qWith longitudinal axis component I _d:

$\left[\begin{array}{c}{I}_d\\ I_q\end{array}\right]=\left[\begin{array}{cc}\cos \mathrm{\&omega;t}& \sin \mathrm{\&omega;t}\\ -\sin \mathrm{\&omega;t}& \cos \mathrm{\&omega;t}\end{array}\right]\&times;\left(\left[\begin{array}{cc}1& 0\\ \frac{1}{\sqrt{3}}& \frac{2}{\sqrt{3}}\end{array}\right]\left[\begin{array}{c}{I}_u\\ I_v\end{array}\right]\right)$

Calculate Id and the Iq data quadrature component V that draws voltage through the PI conversion of microprocessor 7 _qLongitudinal axis component V _d, and be calculated as follows and draw motor stator phase voltage amplitude V _DqWith motor magnetic linkage λ:

$V_{\mathrm{dq}}=\sqrt{{\mathrm{<figure-callout\; id="2"\; label="v\; d"\; filenames="H2008102048828E0000011.png"\; state="\{\{state\}\}">v</figure-callout>}}_d^{}+{\mathrm{<figure-callout\; id="2"\; label="v\; q"\; filenames="H2008102048828E0000011.png"\; state="\{\{state\}\}">v</figure-callout>}}_q^{}},$ $\mathrm{\&lambda;}=\frac{v_{\mathrm{dq}}}{\mathrm{\&omega;}},$

The magnetic linkage of magneto 5 is its inherent characteristic, and its value can change along with the permanent magnet variation of temperature, and the ratings of establishing magneto 5 magnetic linkages is λ _Cal, when the λ value that records at (0.8 λ _Cal, 1.2 λ _Cal) interval in the time, judge the not obviously demagnetization of permanent magnet magnetic of magneto 5, when the λ value that records at (0,0.8 λ _Cal) interval in the time, judge that magneto 5 has tangible demagnetization phenomenon.

Microprocessor 7 also can be connected to vehicle-mounted LCDs, controls the vehicle-mounted LCDs information that gives a warning when microprocessor 7 judges that permanent magnets have obvious demagnetization.

Claims (4)

1. the demagnetized state supervising device of a permanent magnet of permanent magnet motor, comprise battery (1), inverter (2) and magneto (5), battery (1) is connected with inverter (2) with lead, after changing three-phase alternating current into, the direct current that inverter (2) is exported battery use lead to be connected again with magneto (5), it is characterized in that: also comprise U phase current sensor (31), V phase current sensor (32), speed pickup (6) and microprocessor (7), microprocessor (7) has numerical operation, the PI conversion, data storing and information output function, connect in the three-phase conducting wire of inverter (2) and motor (5), U phase line and V phase line are connected in series U phase current sensor (31) and V phase current sensor (32) respectively, a speed pickup (6), U phase current sensor (31) are gone up and connect to magneto (5), V phase current sensor (32) all uses lead to be connected with microprocessor (7) with speed pickup (6).

2. the demagnetized state supervising device of permanent magnet of permanent magnet motor as claimed in claim 1 is characterized in that: microprocessor (7) employing DSP microprocessor.

3. the demagnetized state supervising device of permanent magnet of permanent magnet motor as claimed in claim 1 or 2, it is characterized in that: microprocessor (7) also is connected with vehicle-mounted LCDs, when microprocessor (7) judged that permanent magnet has obvious demagnetization, microprocessor (7) was controlled the vehicle-mounted LCDs information that gives a warning.

4. the demagnetized state method for supervising of a permanent magnet of permanent magnet motor is undertaken by phase current and the angular velocity of rotation of measuring magneto when magneto is in the zero moment control model, it is characterized in that: carry out successively as follows:

Choose the U phase line and the V phase line respectively is connected in series U phase current sensor and V phase current sensor on lead from three-phase supply to magneto that supply with, establishing the U phase current that records is I _u, the V phase current is I _v

On magneto and connect an angular-rate sensor, establishing the motor angular velocity of rotation that records is ω, and the time of experiencing during measurement is t;

The U phase current I that U phase current sensor is recorded _u, the V phase current I that records of V phase current sensor _vThe motor angular velocity of rotation ω that records with angular-rate sensor and these five data of time t of experience all input to microprocessor, and do following the processing to draw electric current quadrature component I _qWith electric current longitudinal axis component I _d:

$\left[\begin{array}{c}{I}_d\\ I_q\end{array}\right]=\left[\begin{array}{cc}\cos \mathrm{\&omega;t}& \sin \mathrm{\&omega;t}\\ -\sin \mathrm{\&omega;t}& \cos \mathrm{\&omega;t}\end{array}\right]\&times;\left(\left[\begin{array}{cc}1& 0\\ \frac{1}{\sqrt{3}}& \frac{2}{\sqrt{3}}\end{array}\right]\left[\begin{array}{c}{I}_u\\ I_v\end{array}\right]\right)$

Calculate Id and Iq data draw the quadrature component V of voltage through the PI conversion of microprocessors (7) _qLongitudinal axis component V _d, and be calculated as follows and draw motor stator phase voltage amplitude V _DqWith motor magnetic linkage λ:

$V_{\mathrm{dq}}=\sqrt{v_d^2+v_q^2},$ $\mathrm{\&lambda;}=\frac{v_{\mathrm{dq}}}{\mathrm{\&omega;}},$

If the ratings of magneto magnetic linkage is λ _Cal, when the λ value that records at (0.8 λ _Cal, 1.2 λ _Cal) interval in the time, microprocessor is judged the not obviously demagnetization of permanent magnet magnetic of magneto, when the λ value that records at (0,0.8 λ _Cal] interval in the time, microprocessor judges that magneto has tangible demagnetization phenomenon.

Images