CN101662256A - Control method of six-phase ten-pole permanent magnet fault-tolerant motor with strong fault-tolerant capability - Google Patents

Abstract

The invention relates to a control method of a six-phase ten-pole permanent magnet fault-tolerant motor with strong fault-tolerant capability. The control method utilizes the current direct control strategy and does not need the links of fault diagnosis and fault identification, when a winding or a power tube of the motor appears the faults of one-phase, two-phase and three-phase (including open circuit fault, short circuit fault and the combination thereof), the motor can be transited to the fault states of five-phase, four-phase and three-phase from the six-phase normal state smoothly, the output rotational speed of the motor is unchanged, and 100%, 80% and 60% of rated power can be respectively outputted, thereby realizing the strong fault-tolerant control of a system. Therefore, the control method of the motor control system is applicable to aerospace, field mining and military occasions with the requirements of high reliability and high efficiency.

Description

Six-phase ten-pole permanent magnet fault-tolerant motor control method with strong fault tolerance ability

One, technical field:

Involved in the present invention is the six-phase ten-pole permanent magnet fault-tolerant motor control method with strong fault tolerance ability.

Two, background technology:

In recent years, ac motor speed control technology has obtained developing rapidly, and forward high frequencyization, digitlization and intelligent direction development.At some special dimensions, as fields such as Aero-Space, military affairs, open-air mining, security reliability is an important indicator, so the fault-tolerant control ability the during system failure just becomes very distinct issues.Fault rear motor phase-deficient operation, bigger fluctuation will appear in the output torque, produce bigger machinery noise, and the overall performance of system reduces greatly, even can not work.The appearance of fault tolerant permanent magnet machine and control system thereof has improved the security reliability of electric machine control system, has been widely applied to aviation field.

Abroad, reliability engineering is development very fast, it roughly divides two stages, one is to be the primary stage of sign with redundant technique (representational be two redundancy technologies), one is to be the advanced stage of sign with the fault-toleranr technique, there is the difference of matter in this two stages, and its motive force of development is by computer technology and electric machines control technology developing by leaps and bounds in the nineties in last century.The nineties in last century, the development of DSP technology (digital signal processor) makes the computational speed of computer bring up to a new height, and electric machines control technology has also developed into a very high condition.After the nineties in last century, can regard each phase and the corresponding inverter leg of polyphase machine as modular construction fully, situation according to the system failure, give an order by software, the reconstruct of realization system, for example six-phase motor can reconstitute five-phase induction motor, and control method is respective change also, but can guarantee that final performance is constant.This intellectual technology one occurs, and just it is used among the aircraft industry abroad.1996, professor Mecrrow of Britain Newcastle university utilizes the related table between magnetic linkage, electric current and the rotor-position, proposed to carry out fault identification and fault-tolerant control by the mode of tabling look-up, this control is simple, easily realizes digitlization, but because the fault-tolerant motor of different capacity grade, relation between its magnetic linkage, electric current and the position is also different, need remeasure its related table, therefore, the workload of early-stage preparations is bigger, and the transplantability of this control algolithm is not strong simultaneously; 1999, Jiabing professor Wang of Britain Shefield university has proposed the optimum torque control strategy, this control strategy is being realized under the fault-tolerant control precondition, guarantees the output of motor copper loss and torque ripple minimization, can make machine operation at Heng Zhuanjuqu and Heng Gongshuaiqu.2005, professor SilverioBolognani of Italy Padova university proposes the Current Control Strategy after the fault, this control strategy carries out Current Control by some constraintss, when guaranteeing that the situation of one phase or adjacent two-phase open circuit fault takes place electric system, under the condition that satisfies output torque pulsation minimum and non-zero-sequence current, motor still can be exported enough average torques, to realize the fault-tolerant control of system.

But only to a phase short circuit and an open circuit fault, the two-phase open circuit fault has carried out fault-tolerant control to above control algolithm, does not possess polyphase windings or power tube opens circuit simultaneously and the fault-tolerant ability of short trouble; In addition, failure diagnosis and identification that above algorithm will rely on hardware fully realize, need pick out fault by hardware and reach corresponding fault case mutually, software carries out corresponding algorithm switching more then, has increased the complexity of system, and the programming difficulty is big (especially adopting assembler language), the execution cycle of whole algorithm is long, reduced the real-time and the Current Control precision of system's control,, be more prone to cause current distortion especially in the high-speed cruising occasion.Therefore, the new control method of expectation invention can overcome above deficiency, realizes the strong fault tolerance ability of electric machine control system.

At present domestic only have minority colleges and universities that redundancy structure is being studied, and fault-toleranr technique is not launched research, more do not have the application case of fault-toleranr technique

Three, summary of the invention:

The present invention proposes a kind of current direct control method with strong fault tolerance ability of novelty, need not the strong fault tolerance ability of failure diagnosis with regard to feasible system, promptly when a phase, two-phase and three-phase fault take place in the winding of motor or power tube (comprising open circuit fault, short trouble and their combination), the motor output speed is constant, and exportable 100%, 80%, 60% the rated power of difference.Therefore,, simplified the complexity of software and hardware, and reduced the dependence of control algolithm hardware circuit in the strong fault tolerance ability while of the system of assurance.

The strong fault tolerance control strategy of permanent magnet fault-tolerant motor control system of the present invention is: when motor and control system operate as normal thereof, in each control cycle, utilize the pulse signal of position transducer, calculate the position and the rotating speed of motor, export given electromagnetic torque T by the pi regulator of der Geschwindigkeitkreis ^*(t), utilize direct control algolithm of electric current and the position signalling of calculating above to obtain the given current i of each phase winding _j ^*(t), compare with detected transient current, stagnating to encircle by numeral obtains corresponding pwm pulse signal, acts on the fault tolerant permanent magnet machine by drive circuit, shown in figure (1).When motor and control system thereof broke down, system excised fault mutually by the protective circuit of hardware at once, prevents secondary failure.Simultaneously, fault-signal does not participate in the control algolithm of software, and the program of each control cycle after the fault is constant, promptly do not need the algorithm of corresponding failure to switch, electric current direct control method in the algorithm guarantees the average torque that output is certain at this moment, promptly work as system one phase takes place, when two-phase and three-phase fault, motor exports 100% respectively, 80% and 60% nominal torque, and the pulsating quantity of the pi regulator of der Geschwindigkeitkreis assurance electromagnetic torque within the range of permission, thereby make that the motor output speed after the fault is constant, and can export 100% respectively, 80% and 60% rated power, the strong fault tolerance ability of realization system.

Core of the present invention is in the proposition of the direct control algolithm of electric current.The direct control algolithm of electric current is derived according to the power conservation principle of motor and is drawn, and the electromagnetic torque of motor can be expressed as when the motor operate as normal:

$T_e\left(t\right)=\frac{1}{{\mathrm{\ω}}_m}\underset{j=1}{\overset{6}{\mathrm{\Σ}}}(\underset{m}{\mathrm{\Σ}}{e}_{\mathrm{jm}}\left(t\right)\×\underset{n}{\mathrm{\Σ}}{i}_{\mathrm{jn}}\left(t\right))---\left(1\right)$

e _Jm(t) refer to the unloaded back-emf of j phase winding m subharmonic, i _Jn(t) refer to the nth harmonic electric current of j phase winding, ω _mThe mechanical angle speed that refers to motor.By the design of winding back emf sine degree, to ignore the harmonic components in the unloaded back-emf, and control by the sine wave of phase current, formula (1) can be expressed as:

$T_e\left(t\right)=\underset{j=1}{\overset{6}{\mathrm{\Σ}}}\left\{{\mathrm{p\ψ}}_m\cos \right[{\mathrm{p\ω}}_{m}t-\frac{(j-1)\mathrm{\π}}{3}]\·i_m\cos [{\mathrm{p\ω}}_{m}t-\frac{(j-1)\mathrm{\π}}{3}-\mathrm{\γ}\left]\right\}=3{\mathrm{p\ψ}}_m{i}_m\cos \left(\mathrm{\γ}\right)---\left(2\right)$

P refers to the magnetic pole logarithm of motor, ψ _mRefer to that permanent magnet is coupled to the magnetic linkage maximum of armature winding, i _mRefer to the peak current of armature winding, γ refers to the current hysteresis relief angle.In order to make motor can export rated power, then make electromagnetic torque equal constant given torque, that is:

T _e(t)＝T ^*(t) (3)

Normal state then, the given electric current of j phase winding can be expressed as:

${i_j}^{*}\left(t\right)=\frac{T^{*}\left(t\right)}{3{\mathrm{p\ψ}}_m\cos \left(\mathrm{\γ}\right)}\cos [{\mathrm{p\ω}}_{m}t-(j-1)\mathrm{\π}/3)-\mathrm{\γ}]---\left(4\right)$

When open circuit fault appearred in motor k phase winding, then the electromagnetic torque of motor was expressed as:

$T_{\mathrm{eo}}\left(t\right)=\underset{j\≠k}{\overset{6}{\mathrm{\Σ}}}\left\{{\mathrm{p\ψ}}_m\cos \right[{\mathrm{p\ω}}_{m}t-\frac{(j-1)\mathrm{\π}}{3}]\·i_m\cos [{\mathrm{p\ω}}_{m}t-\frac{(j-1)\mathrm{\π}}{3}-\mathrm{\γ}\left]\right\}---\left(5\right)$

$={\mathrm{p\ψ}}_m{i}_m\×[\frac{5\cos \left(\mathrm{\γ}\right)}{2}-\frac{\cos (2{\mathrm{p\ω}}_{m}t-\mathrm{\γ}-2(k-1)\mathrm{\π}/3)}{2}]$

When short trouble appearred in motor k phase winding, then the electromagnetic torque of motor was expressed as:

$T_{\mathrm{es}}\left(t\right)=\underset{j\≠k}{\overset{6}{\mathrm{\Σ}}}\left\{{\mathrm{p\ψ}}_m\cos \right[{\mathrm{p\ω}}_{m}t-\frac{(j-1)\mathrm{\π}}{3}]\·i_m\cos [{\mathrm{p\ω}}_{m}t-\frac{(j-1)\mathrm{\π}}{3}-\mathrm{\γ}\left]\right\}+{\mathrm{p\ψ}}_m\cos [{\mathrm{p\ω}}_{m}t-\frac{(k-1)\mathrm{\π}}{3}]\·i_k---\left(6\right)$

$={\mathrm{p\ψ}}_m{i}_m\×[\frac{5\cos \left(\mathrm{\γ}\right)}{2}-\frac{\cos ({2\mathrm{p\ω}}_{m}t-\mathrm{\γ}-2(k-1)\mathrm{\π}/3)}{2}]+{\mathrm{p\ψ}}_m\cos [{\mathrm{p\ω}}_{m}t-\frac{(k-1)\mathrm{\π}}{3}]\×i_k$

I in the formula _kRefer to the short circuit phase current.In order to guarantee motor when breaking down, motor can be exported corresponding power, that is:

T _eo(t)＝T _es(t)＝T ^*(t) (7)

Then when open circuit fault took place, the given electric current of normal phase winding can be expressed as:

${i_{\mathrm{jo}}}^{*}\left(t\right)=\frac{T^{*}\left(t\right)}{{\mathrm{p\ψ}}_m[\frac{5\cos \left(\mathrm{\γ}\right)}{2}-\frac{\cos (2{\mathrm{p\ω}}_{m}t-\mathrm{\γ}-2(k-1)\mathrm{\π}/3)}{2}]}\×\cos [{\mathrm{p\ω}}_{m}t-(j-1)\mathrm{\π}/3)-\mathrm{\γ}]---\left(8\right)$

When being short-circuited fault, the given electric current of normal phase winding can be expressed as:

${i_{\mathrm{js}}}^{*}\left(t\right)=\frac{T^{*}\left(t\right)-{\mathrm{p\ψ}}_m\cos [{\mathrm{p\ω}}_{m}t-\frac{(k-1)\mathrm{\π}}{3}]\×i_k}{{\mathrm{p\ψ}}_m[\frac{5\cos \left(\mathrm{\γ}\right)}{2}-\frac{\cos (2{\mathrm{p\ω}}_{m}t-\mathrm{\γ}-2(k-1)\mathrm{\π}/3)}{2}]}\×\cos [{\mathrm{p\ω}}_{m}t-(j-1)\mathrm{\π}/3)-\mathrm{\γ}]---\left(9\right)$

By formula (8) and (9) as can be seen, on the one hand, the mean value of given current amplitude is 1.2 times of normal state, and phase angle and frequency are constant, and then the average output power of compensate for failed phase, realizes fault-tolerant; On the other hand, if by formula (8) and formula (9) calculate given electric current, because given current amplitude is the function of fault phase k and fault type thereof, therefore must diagnose out concrete fault phase and fault type thereof by the fault identification link, carry out corresponding algorithm again and switch, certainly will there be identical problem in this with the tolerant fail algorithm that external expert proposes.

But, be expressed as formula (8) and formula (9) being changed a form:

${i_{\mathrm{jo}}}^{*}\left(t\right)=\frac{{T_o}^{*}\left(t\right)}{{3\mathrm{p\ψ}}_m\cos \left(\mathrm{\γ}\right)}\×\cos [{\mathrm{p\ω}}_{m}t-(j-1)\mathrm{\π}/3)-\mathrm{\γ}]---\left(10\right)$

${i_{\mathrm{js}}}^{*}\left(t\right)=\frac{{T_s}^{*}\left(t\right)}{{3\mathrm{p\ψ}}_m\cos \left(\mathrm{\γ}\right)}\×\cos [{\mathrm{p\ω}}_{m}t-(j-1)\mathrm{\π}/3)-\mathrm{\γ}]---\left(11\right)$

Wherein:

${T_o}^{*}\left(t\right)=\frac{{6T}^{*}\left(t\right)\·\cos \left(\mathrm{\γ}\right)}{5\cos \left(\mathrm{\γ}\right)-\cos ({2\mathrm{p\ω}}_{m}t-\mathrm{\γ}-2(k-1)\mathrm{\π}/3)}---\left(12\right)$

${T_s}^{*}\left(t\right)=\frac{6(T^{*}\left(t\right)-{\mathrm{p\ψ}}_m\cos [{\mathrm{p\ω}}_{m}t-\frac{(k-1)\mathrm{\π}}{3}]\×i_k)\·\cos \left(\mathrm{\γ}\right)}{5\cos \left(\mathrm{\γ}\right)+2\cos \left(\frac{\mathrm{\π}+2\mathrm{\γ}}{4}\right)\sin ({2\mathrm{p\ω}}_{m}t-\frac{8\mathrm{k\π}-6\mathrm{\γ}-11\mathrm{\π}}{12})}---\left(13\right)$

Comparison expression (4), (10) and (11) as seen, the form of expression formula is the same, just the molecule in the formula (4) is T ^*And formula (10) and (11) are respectively T (t), _o ^*(t) and T _s ^*(t).By the PI regulating characteristics as can be known, when the input speed difference of pi regulator is non-vanishing (but speed discrepancy satisfies motor output characteristic index), exportable T _o ^*(t) and T _s ^*So electric current is given just needn't distinguish T again (t), _o ^*(t) and T _s ^*(t), only need the output T of same pi regulator ^*(t) just, can represent that need not failure diagnosis information algorithm and algorithm and switch, as shown in Figure 1, promptly the expression formula of electric current direct control method is expressed as by identical expression formula so electric current is given:

${i_j}^{*}\left(t\right)=\frac{T^{*}\left(t\right)}{3{\mathrm{p\ψ}}_m\cos \left(\mathrm{\γ}\right)}\×\cos [{\mathrm{p\θ}}_m-\frac{(j-1)\mathrm{\π}}{3}-\mathrm{\γ}],j\≠k---\left(14\right)$

Here it is core content of the present invention.

It is different with the algorithm that external expert proposes.The tolerant fail algorithm that external expert proposes is made up of three analytic expressions, the corresponding normal state of difference, the attitude that opens circuit and short circuit attitude are during system works, the algorithm that must rely on failure diagnosis and identification signal thereof to carry out under the corresponding state switches, and has therefore increased the complexity of software and hardware.

And the direct control algolithm of electric current of the present invention, its analytic expression only has one, therefore fault diagnosis signal and algorithm do not switch, simultaneously, because interior ring adopts the ring control that stagnates, the dynamic response of interior ring is much larger than der Geschwindigkeitkreis, if outer shroud PI parameter designing is reasonable, the rotating speed of motor difference can be stabilized in certain static difference, and promptly this PI parameter will guarantee that system can both steady operation at normal state and fault case, so the quality of PI parameter designing has determined the stability and the fault-tolerance of system.As shown in Figure 1, a pi regulator is only arranged, therefore, the difficulty of PI parameter designing reduces a lot, shows the parameter value when the feasible PI parameter of normal state can be used as fault case fully by test.

For reaching above-mentioned specification requirement, technical solution of the present invention is, hardware system detects the loop by major loop, and the control loop three parts are formed, and it does not have fault diagnosis algorithm and algorithm switching part, and this is its feature.Major loop is connected by six-phase ten-pole permanent magnet fault-tolerant motor (1), power inverter (2), and receives power supply grid by power inverter; Detecting the loop is made up of position transducer (7) and current sensor (6); Control loop is connected in control unit (4) based on digital signal processor (DSP) by analog to digital converter (5), produces the power inverter control signal, is connected in the drive circuit (3) of converter again; When a certain phase of motor, two-phase and three phase windings or controller break down (comprising open circuit fault, short trouble and combination thereof), utilize relay directly that fault is isolated, as shown in Figure 3, this moment, DSP did not need fault identification signal and corresponding algorithm to switch.

Advantage of the present invention:

(1) guarantees a phase, two-phase and three phase windings of motor and control system thereof or power tube opens circuit and during short trouble, the output speed of motor is constant, and can export 100%, 80%, 60% rated power respectively, realizes that the strong fault tolerance of system is controlled;

(2) in whole fault-tolerant control, need not failure diagnosis and algorithm and switch, reduced the complexity of system hardware and software, be convenient to the realization of Digital Control System;

(3) whole fault-tolerant control algolithm is little to the dependence of the parameter of electric machine, makes control program have good transplantability and versatility, is convenient to engineering debug;

(4) extend to four phases, five phase even more heterogeneous fault tolerant permanent magnet control system.

Four, description of drawings:

Fig. 1 is based on the six-phase ten-pole permanent magnet fault-tolerant electric motor control system with strong fault tolerance ability of electric current direct control method

The topological diagram of Fig. 2 power inverter

Fig. 3 is based on the six-phase ten-pole permanent magnet fault-tolerant motor of electric current direct control method and the hardware composition frame chart of control system thereof

Designation among Fig. 1 is respectively: n ^*-given rotating speed, n-actual speed, T ^*-given torque, θ _mThe position of-rotor, i ₁ ^*～i ₆ ^*The given electric current of-six phase windings, i ₁～i ₆The actual current of-six phase windings, f (θ _m, j, γ)-analytical expression of the direct control algolithm of electric current, the drive signal of pwm1～pwm24-power tube.

Designation among Fig. 2 is respectively: T1～T24-main power tube, and D1～D24-fly-wheel diode, R1～R6-sampling resistor, K1～K6-has the relay of normally closed interlock.

Numbering title among Fig. 3 in each block diagram is respectively: 1, six-phase ten-pole permanent magnet fault-tolerant motor, 2, power inverter, 3, the drive circuit of converter, 4, based on the directly actuated digital controlled signal processor of electric current, 5, modulus converter A/D, 6, current sensor, 7, position transducer.

Five, specific implementation method:

Narrate specific implementation method of the present invention and operation principle and process with reference to the accompanying drawings.As shown in Figure 2, the main power topology that each phase winding of motor adopts the H bridge-type has realized the electrical isolation between motor windings, and can utilize relay that fault is excised from bus, avoids the generation of secondary failure.

Permanent magnet fault-tolerant motor control system based on the electric current Direct control strategy of the present invention comprises six-phase permanent magnet fault-tolerant motor (1), the two major loop that is formed by connecting of power inverter (2); Form by current sensor (6) and position transducer (7) and to detect the loop, be connected in control system (4), form control loop by the drive circuit (3) of converter again based on digital signal processor (DSP) by analog-digital conversion a/d (5).Power inverter adopts IGBT power tube or power field effect pipe; Current sensor adopts Hall element, and transducer converts the current signal on the major loop analog voltage signal of light current to, enters modulus converter A/D, by it analog signal conversion is become digital signal, gives DSP control system again; Position transducer can adopt photoelectric code disk or rotary converter, in conjunction with DSP, and utilizes the M/T method pulses switch of transducer to be become the position and the tach signal of motor; Signal and the of the present invention electric current direct control method obtained according to above DSP, in DSP, calculate the given electric current of each phase winding by real-time software, according to formula of the present invention (14), determine the pwm pulse signal of each phase winding by the stagnant ring of numeral, via the drive circuit of converter, send 24 road pulse signals and remove to control power inverter in the major loop.Failure diagnosis and protective circuit utilize on current sensor and the H bridge adopt resistance detection to signal carry out failure diagnosis; if there is fault to take place; this circuit is given the drive circuit of converter by hardware output protection signal; block the drive signal of corresponding failure phase; and send cut-off signal for the relay in the fault phase H bridge master power model; fault is gone out on the bus to excise mutually, but it does not influence control algolithm, control algolithm is constant naturally.The workflow by dsp software and the motion flow of fault secure circuit are as seen; when system breaks down; Control Software algorithm in the DSP need not the output signal of failure diagnosis and protective circuit; therefore; fault tolerant permanent magnet machine control based on the direct control algolithm of electric current of the present invention need not to carry out the algorithm switching, and the fault tolerance of feasible system.

Claims (3)

1. six-phase ten-pole permanent magnet fault-tolerant motor control method based on the electric current direct control method with strong fault tolerance ability, it is characterized in that, when one phase takes place for the winding or the power tube of motor, (comprise open circuit fault when two-phase and three-phase fault, short trouble and their combination), without failure diagnosis and identification link, and only use the electric current direct control method, motor automatically is smoothly transitted into five phases from six phase normal states, four phase and three-phase fault attitudes, the motor output speed is constant simultaneously, difference exportable 100%, 80%, 60% rated power is realized the strong fault tolerance control of system.

2. the electric current direct control method of a novelty, its control flow is: obtain the position and the tach signal of motor by position transducer, in each control cycle, utilize outer shroud rotating speed pi regulator to obtain the given torque T of motor normal state or fault case ^*(t),, do not need fault diagnosis signal and algorithm to switch,, directly calculate the given current i of normal phase winding by the direct control algolithm of electric current in conjunction with the position signalling of rotor _j ^*(t), utilize numeral to stagnate to encircle again and obtain corresponding pwm pulse signal, act on the six-phase ten-pole permanent magnet fault-tolerant motor by power inverter at last, reach the purpose of speed governing and strong fault tolerance control.

3. the direct control algolithm of the electric current of a novelty, this arithmetic analysis formula is:

${i_j}^{*}\left(t\right)=\frac{T^{*}\left(t\right)}{3p{\mathrm{\ψ}}_m\cos \left(\mathrm{\γ}\right)}\×\cos [p{\mathrm{\θ}}_m-\frac{(j-1)\mathrm{\π}}{3}-\mathrm{\γ}],j\≠k$

T ^*(t) show and decide electromagnetic torque, i _j ^*(t) the make a comment or criticism given electric current of normal phase winding, p refers to the magnetic pole logarithm of motor, ψ _mRefer to that permanent magnet is coupled to the magnetic linkage maximum of armature winding, θ _mThe position mechanical angle that refers to rotor, γ refer to electrical degree after the current hysteresis, and k refers to the fault phase.The given T of torque ^*(t) can obtain by the rotating speed pi regulator, this algorithm is only relevant with rotor-position simultaneously, and is irrelevant with the fault number of phases that occurs in the system and fault type, therefore, system is when fault case, and Control Software need not fault diagnosis signal and algorithm switches, and the control of the strong fault tolerance of feasible system.

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