CN203708167U

CN203708167U - Driver suitable for superspeed PMSM

Info

Publication number: CN203708167U
Application number: CN201320880654.9U
Authority: CN
Inventors: 张前
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-12-30
Filing date: 2013-12-30
Publication date: 2014-07-09
Anticipated expiration: 2023-12-30

Abstract

The utility model discloses a driver suitable for a superspeed PMSM; the driver comprises a power circuit, a control circuit and a communication circuit; the driver is characterized in that a BUCK converter (3) and a passive lossless soft switch (2) are combined on a power input end so as to provide flat supply voltage for the motor, and switch stress can be eliminated; HALL sensor position detection and counterelectromotive force method position detection are compatible; a counterelectromotive force method starting phase has a resistance current limit function; a detection position signal low level duration method is used to calculate rotation speed; the drive can obviously reduce stator rotor eddy current loss of the superspeed PMSM (rotation speed is bigger than 50000rpm).

Description

A kind of driver that is applicable to ultrahigh speed permagnetic synchronous motor

Technical field

The utility model relates to super high speed motor control field (rotating speed is greater than 50000rpm), is specifically related to middle low power ultrahigh speed permagnetic synchronous motor driver.

Background technology

In ultrahigh speed magneto, eddy current loss is the important component of the loss of electric machine, can adopt and reduce silicon steel sheet thickness for stator eddy current loss, add the measures such as water-cooled, but for rotor eddy current loss, but there is no desirable coping style, and rotor is in motor body inside, radiating condition is poor, very easily causes accumulation of heat to cause even demagnetization of magnet steel heating.

Most ultrahigh speed permanent magnet motor drives is all to adopt SPWM or the control of SVPWM mode, for middle slowspeed machine, it is more satisfactory that it controls effect, but because inductance between super high speed motor bulk line is extremely low, much in 100uH, the current fluctuation that device for power switching copped wave causes is very obvious, thereby need the switching frequency that greatly improves device for power switching just can export more satisfactory sinusoidal current, perfect switch frequency need reach above (the De S of 200kHz, Rajne M, Poosapati S, et al. Low-inductance axial flux BLDC motor drive for more electric aircraft[J]. IET Power Electronics, 2012, 5 (1): 124-133), but in most cases, device for power switching in the market comprises MOSFET, IGBT etc., cannot reach switching frequency and power requirement simultaneously, therefore the sine-wave current that ultrahigh speed permagnetic synchronous motor driver in the market simulates contains great high-frequency harmonic composition (as Fig. 4), these high-frequency harmonics are the main causes that causes rotor eddy current loss.Generally face following problem at ultrahigh speed magneto control field: 1, how in the situation that directly copped wave can not be exported ideal sinusoidal electric current, reduce as far as possible the rotor eddy current loss that current harmonics causes; 2, in driver design, also there is minority use preposition BUCK circuit voltage regulating mode, but cause in the copped wave of power switch place that again copped wave place causes inefficiency to the serious High-frequency Interference of power supply and copped wave loss merely; 3, when super high speed motor Based on Back-EMF Method starts at present, generally adopt syllogic to start, how to make motor start smoothly.

Summary of the invention

The technical problem that the utility model solves is: the utility model provides the control strategy of a kind of low interference, low current fluctuation, can obviously reduce the rotor temperature rise being caused by rotor eddy current loss; Adopt soft switch to eliminate the switch stress of BUCK converter copped wave place; Super high speed motor Based on Back-EMF Method cannot guarantee necessarily to start successfully while startup, the utility model add startup current-limiting resistance module can guarantee motor in the time there is deviation in the phase sequence of powering motor and driver not damaged.

Technical solution of the present utility model is: the utility model has adopted preposition Lossless Passive Soft Switching Methods BUCK circuit, carries out chopper control to replace the at present general direct mode in the copped wave of inverter place in inverter prime; The utility model can adopt Based on Back-EMF Method control, startup stage adopt syllogic to start, due to motor internal resistance and inductance minimum, the safety when guaranteeing to start, on bus, series resistance, with limiting starting current, is fallen resistive short by power switch pipe when motor reaches certain rotating speed; The utility model has designed two kinds of rotor-position detection modes, can adopt the control of Hall approach sensor for the motor of built-in Hall transducer, can adopt Based on Back-EMF Method control for the motor of placement position detection element not, both select by 3 × 3 terminals; The utility model medium velocity calculates and adopts the low level time method that detects, and detects the low duration of any road signal in three-phase control signal and realizes speed closed loop PID function.

The utility model is compared with existing driver, advantage is: driver output voltage is stable square wave, compare SPWM mode and the SVPWM control mode of inputting analog sine electric current after copped wave, current waveform is relatively steady, without high frequency clutter (as Fig. 5), can effectively reduce the eddy current loss on electric machine rotor, obviously reduce superspeed permanent magnet motor rotor heating, soft switch is combined with BUCK converter and is placed in three phase inverter bridge front end, coordinate the control of PWM variable frequency control module, can realize smoothly the adjusting of driver to rotating speed, and reduce the switch stress of power switch pipe, improve the useful life of drive efficiency and power switch pipe, the utility model, in order to guarantee Based on Back-EMF Method clean boot, adopts series resistor method limiting starting current, even phase sequence exists deviation also can not damage motor and driver can guarantee the startup of Based on Back-EMF Method syllogic time, the utility model adopts 3 × 3 control signals to select terminal (as Fig. 3), and back-emf signal Sa, Sb, Sc and Hall signal Ha, Hb, Hc can be input to single-chip microcomputer by three chip interfaces, without with six interfaces, saves chip interface resource.

Accompanying drawing explanation

Fig. 1 is ultrahigh speed permagnetic synchronous motor activation configuration block diagram of the present utility model.

Fig. 2 is ultrahigh speed permagnetic synchronous motor actuator power control system circuit diagram of the present utility model.

Fig. 3 is control signal selecting side subgraph.

Current waveform figure when Fig. 4 is the operation of SVPWM mode control motor.

Current waveform figure when Fig. 5 is the operation of the utility model control motor.

In figure: 1, current-limiting resistance module, 2, Lossless Passive Soft Switching Methods, 3, BUCK converter, 4, current sensor module, 5, inverter, 6, host computer, 7, JTAG module, 8, PWM variable frequency control module, 9, CAN bus module, 10, Logic control module, 11, back-emf signal processing module, 12, control signal selects terminal.

Embodiment

The utility model adopts preposition soft switch BUCK circuit chopping way to regulate busbar voltage, power control circuit topological structure is as Fig. 2, input voltage Vi is after BUCK converter 3, supply with motor inverter 5 galvanic currents and press Vo, power switch T is as the chopping switch of BUCK converter 3, electric capacity 13 is for the interference of filtering Vi, and diode 14 guarantees can be because the energy storing in inductance L 1 produces the voltage higher than Vi at C2 two ends in commutation Dead Time.

In BUCK converter 3, inductance L 1 and capacitor C 2 form a low pass filter to obtain straight output current and voltage, and its value can be according to following empirical equation:

（1）

（2）

Wherein, for output voltage, for the ripple current of designing requirement, for the ripple voltage of designing requirement, for duty ratio, T is chopping cycle, according to formula (1) (2), calculates and guarantees current/voltage fluctuation required L1 and C2 in desired extent.

L2, D3, C3 and D4 form Lossless Passive Soft Switching Methods 2 after being connected to T, and this soft switch circuit is without additional auxiliary switch, and non-resistance element can effectively reduce the switch stress of switch transistor T, guarantees switch transistor T zero current passing and shutoff.The value mode of its L2, C3 is as follows:

(1) L2<<L1, guarantees that L2 value is much smaller than L1, and its occurrence can be 0.1-0.01 times of L1;

(2) peak current in L2 during resonance:

（3）

In formula for peak current in L2, for the value of capacitor C 3, for the value of inductance L 2, for the output current of BUCK converter 3, wherein value within the permission electric current of inductance L 2 and switch transistor T, and need to guarantee be greater than , can determine thus C3,

C3 two ends crest voltage during resonance:

（4）

(3) obtain harmonic period according to L2, C3 = ;

(4) according to the harmonic period of obtaining determine the ON time of switch transistor T in BUCK circuit , desirable , determine the monocycle ON time of switch transistor T in PWM process, guaranteed switch transistor T monocycle ON time the turn-off time that regulates switch transistor T in constant situation is adjustable duty ratio.

Current-limiting resistance module 1 is for coordinating syllogic to start method, because being a kind of compulsory type, syllogic startup method starts, commutation may be inaccurate, and there is the not corresponding situation of power supply phase sequence, and the inductance resistance of super high speed motor own is minimum, directly startup is abnormally dangerous, thereby adopts series resistor (0.5-3 Ω) to limit the electric current that starts moment, and rotating speed reaches set point (1000-3000rpm) and with power switch T1, resistive short fallen afterwards.

Control signal selects terminal as Fig. 3, with 3 × 3 terminals, in the middle of terminal, 4,5,6 pins connect control chip, 1,2,3 pins meet Ha, Hb, Hc, 7,8,9 pins meet Sa, Sb, Sc, when selection, connect respective signal by wire jumper, can realize with three chip input ports the input of two kinds of control signals, save interface microcontroller resource.

During speed is calculated, detect the low duration t on any road in control signal Sa, Sb, Sc or Ha, Hb, Hc, by formula V= , can obtain speed V(rpm), the rate signal that this kind of computational methods obtain is without averaging, real-time.

Claims

1. a driver that is applicable to ultrahigh speed permagnetic synchronous motor, is characterized in that: after Lossless Passive Soft Switching Methods (2) and BUCK converter (3) combination, apply to inverter (5) front end; Current-limiting resistance module (1) coordinates syllogic to start method in the time adopting back EMF control method, and motor and driver are carried out to current-limiting protection, passes through power switch pipe T1 by resistance R short circuit in the time that rotating speed reaches 1000-3000rpm; Logic control module (10) is by detecting any road low duration computational speed in Sa, Sb, Sc and Ha, Hb, Hc; Control signal selects terminal (12) to carry out the selection of back-emf signal or Hall signal; PWM variable frequency control module (8) is by floatless switch pipe T ON time, and the mode that changes chopping frequency realizes the adjusting to duty ratio.

2. a kind of driver that is applicable to ultrahigh speed permagnetic synchronous motor according to claim 1, it is characterized in that: inverter (5) front-end circuit is made up of Lossless Passive Soft Switching Methods (2), backward diode (14) and BUCK converter (3), soft switch (2) is made up of T, D4, L2, D3 and C3, wherein the left end of the right-hand member of the right-hand member of T, D4, L2 and the upper end of D3 are connected, and the upper end of C3 is connected with the right-hand member of L2; BUCK converter (3) is made up of jointly T, L1, D1 and C2, and D1 upper end is connected with L1 left end, and C2 upper end is connected with L1 right-hand member, between T and BUCK translation circuit (3), connects by soft switch (2); The left end of backward diode (14) is connected with positive source, and right-hand member is connected with the right-hand member of L1 in BUCK converter (3).

3. a kind of driver that is applicable to ultrahigh speed permagnetic synchronous motor according to claim 1, it is characterized in that: current-limiting resistance module (1) is composed in parallel by resistance R and power switch pipe T1, switch transistor T 1 left end is connected with power cathode, and switch transistor T 1 right-hand member is connected with C1, C2, C3, D1, D3 lower end.