CN104807152A - PM motor direct power control constant-air-volume control method and HVAC system using same - Google Patents

Abstract

The invention discloses a PM motor direct power control constant-air-volume control method and an HVAC system using same. The control method comprises the steps of step A, receiving the target air volume IN-CFM through a starting motor; step B, obtaining a corresponding function P=f (n) according to the target air volume IN-CFM; step C, entering a direct power control constant-air-volume control mode: controlling the motor to reach a stable work point (pt, nt) along the function P=f (n) control track; step D, calculating motor real-time input power Pi according to motor operation parameters, wherein delta P=/Pt-Pi/; step E, maintaining the prior work point if delta P is smaller than the set value Pset; step F, calculating whether the speed ring operation time is reached if delta P is larger than or equal to the set value Pset, and maintaining the prior work point if the operation time is not reached; step G, entering the speed control circuit adjusting speed, that is, making pt=Pi and nt=ni, if the time is reached to achieve a novel work point (Pi, ni) on the track, and returning to the step C. The control method and the HVAC system have the advantages that the method is particularly applicable to air volume control in the steady state, the algorithm is concise, the requirement for CPU operation is not high, the cost is low, and the control accuracy is high.

Description

The constant air capacity control of PM motor direct Power Control and the HVAC system of application thereof

Technical field:

The present invention relates to the constant air capacity control of variable speed electric motors, particularly, particularly relate to HVAC system and other variable speed electric motors, particularly systems of the constant air capacity control of PM motor direct Power Control and application thereof.

Background technology:

PM motor, the abbreviation of direct current brushless permanent magnet synchronous motor, may also be referred to as ECM motor, because PM motor environment for use is different, its control model is also different, generally have: the control of constant speed control, constant moment of force and permanent Boiler pressure control etc., permanent Boiler pressure control is in HVAC(HVAC system) be the pattern comparatively commonly used.

In the room ventilation pipeline of domestic air conditioning, static pressure often changes as time goes by, such as because dust deposited in pipeline or plugged filter.Standard static pressure during the nominal system of static pressure also because the installation of pipeline is different often higher than manufacturer laboratory.Permanent Boiler pressure control can bring constant air quantity to user in these cases, thus maintains comfortable ventilation, the effect of freezing or heating under hydrostatic pressure condition widely, and makes system cloud gray model reach energy-efficient.

General constant air capacity control directly installs air volume meter, not only raise the cost, potential losing efficacy because of air volume meter was also brought to cause controlling unsuccessfully, current air-conditioning manufacturer also adopts the constant air capacity control without air volume meter usually, what have will monitor that the change of static pressure carrys out speed governing, some computing formula relate to Logarithmic calculation or higher order polynomial, and this needs the MCU of electric machine controller to have more powerful computing capability, further increases cost.

US Patent No. 4806833 discloses for outside static pressure to change motor speed, obtains permanent wind amount.The change of outside static pressure is that the rotation speed change of the tachometer induction carried by motor calculates, and Wind Coverage Calculation is controlled by the function of moment and rotating speed; US Patent No. 5736823a also discloses a kind of constant air capacity control, is also to be controlled by the function of moment and rotating speed.

The control method of above permanent wind amount uses torque as key control variable, there is following technical problem:

1) moment is a mechanical variables, be difficult to measurements and calculations it, can control accuracy be affected;

Therefore and not bery applicable 2) Torque Control is used for the application of Dynamic controlling, but this permanent Boiler pressure control is a typical lower state controls;

3) Torque Control is comparatively complicated in Electric Machine Control, and best example is that vector controlled realizes a good direct torque, but the precision that this system torque controls is the cost restriction being subject to system hardware and software;

4) moment is not one and allows consumer and governability, understands the characteristic parameter of the operation of system.

In other words: moment is a mechanical variables, not easily directly measures. realize permanent Boiler pressure control by moment as Variable Control, cause computing complicated, cost is higher, and moment is difficult to the management of the energy-conserving and environment-protective of advocating with government and standard is associated, not intuitively.

Summary of the invention:

The object of this invention is to provide HVAC system and other variable speed electric motors, particularly systems of the constant air capacity control of PM motor direct Power Control and application thereof, it is specially adapted to the Boiler pressure control under stable state, algorithm is succinct, less demanding to CPU computing, cost is lower, control accuracy is higher, is conducive to the control of energy-saving and emission-reduction.

The object of the invention is to be achieved by following technical proposals.

The constant air capacity control of PM motor direct Power Control, described PM motor be arranged in HVAC system with drive wind wheel to rotate and have stator module, permanent magnet rotor component and, electric machine controller comprises motor operating parameter testing circuit and microprocessor, it is characterized in that: it comprises the steps:

Steps A) actuating motor controller, the target air volume value IN-CFM receiving or preset;

Step B) obtain corresponding function P=f (n) according to target air volume value IN-CFM, wherein n is rotating speed, and P is power input to a machine;

Step C) enter direct Power Control permanent wind amount control model: starter motor when control motor or motor speed are zero, makes it arrive a stable operating point (p along the control track of function P=f (n) _t, n _t); p _t, n _tbe be positioned at meet permanent wind amount control function P=f (n) track on a pair input power and rotating speed;

Step D) keep direct Power Control permanent wind amount control model: calculate the real-time input power Pi of motor according to motor operating parameter; Calculate Δ P=|Pt-Pi|;

Step e) if power increment value Δ P is less than setting value P _set, keep work on hand point;

Step F) if power increment value Δ P is more than or equal to setting value P _set; Whether the operating time of computational speed ring reaches by power/rotating speed control logic; If the operating time of speed ring does not reach, keep work on hand point;

Step G) if the operating time of speed ring reaches, admission velocity control loop presses Δ n=|ni-nt| governing speed, and ni is real-time rotate speed, realize the new operating point (Pi, ni) on track, even Pt=Pi, nt=ni, get back to step C.

Motor operating parameter testing circuit described above comprises bus current testing circuit and busbar voltage testing circuit, and bus current testing circuit and busbar voltage testing circuit detect real-time bus current I _buswith real-time busbar voltage V _bus, the real-time input power Pi=I of motor _bus× V _bus.

Motor operating parameter testing circuit described above comprises phase line current testing circuit and busbar voltage testing circuit, phase line current testing circuit, busbar voltage testing circuit detect phase current and busbar voltage data are input to microprocessor, real-time phase current and real-time busbar voltage V _busand convert electric current I α, I β on alpha-beta coordinate, voltage V α, V β to, motor real-time input power Pi=3/2(I α V α+I β V β).

Function P=f (n) described above obtains like this: first gather initial data, for several target air volume, be adjusted to high static pressure from low static pressure always, this static pressure wants the actual static pressure scope that can contain application, in the process of regulating static, motor is allowed to be in constant speed control, and by regulating motor speed n and the real-time input power Pi of motor to keep air quantity to be target air volume, and record motor steady-state speed the n now and real-time input power Pi of motor of correspondence, like this, for several target air volume, all create one group of rotating speed n and the real-time input power Pi of motor, then corresponding function P=f (n) of each target air volume in several target air volume is produced by the method for curve.

If outside input target air volume value IN-CFM is not equal to several target air volume of said determination one of them, interpolation method can be passed through, the Fitting Calculation inputs corresponding function P=f (n) of target air volume value IN-CFM with any outside, achieves the permanent Boiler pressure control of omnidistance arbitrary target air quantity.

The real-time input power Pi of motor described above adopts wave digital lowpass filter to process, to real-time bus current I _bus, real-time busbar voltage V _busdata acquisition time, adopt wave digital lowpass filter process.

Functional relation P=f (n) described above is polynomial function a: P=C ₁+ C ₂× n+...+C _m× n ^m-1, wherein C ₁, C ₂..., C _mbe coefficient, n is motor speed value, the corresponding one group of C of each target air volume ₁, C ₂..., C _mcoefficient also stores, and microprocessor obtains one group of corresponding C according to the target air volume value IN-CFM of input by look-up table or interpolation method ₁, C ₂..., C _mcoefficient, thus obtain functional relation P=f (n).

Functional relation P=f (n) described above is second order function a: P=C ₁+ C ₂× n+C ₃× n ².

A kind of application rights requires the HVAC system of the constant air capacity control of PM motor direct Power Control described in 1 to 8, comprise PM motor and wind wheel, PM motor drives wind wheel rotate and have stator module, permanent magnet rotor component and electric machine controller, and PM motor realizes permanent Boiler pressure control by direct Power Control.

A kind of application rights requires the variable speed electric motors, particularly system of the constant air capacity control of PM motor direct Power Control described in 1 to 8, comprise variable speed electric motors, particularly and wind wheel, variable speed electric motors, particularly drives wind wheel rotate and have stator module, rotor assembly and electric machine controller, and variable speed electric motors, particularly realizes permanent Boiler pressure control by direct Power Control.

The present invention compared with prior art, has following effect: 1) utilize laboratory facilities to obtain the target air volume value CFM of several inputs _setcorresponding function P=f (n), utilizes function P=f (n) to be converted into the calculated value Pt of corresponding power input to machine according to motor speed n, detects real-time bus current I _busor phase current and real-time busbar voltage V _busconverse the electric current I α on vector alpha-beta coordinate, I β and voltage V α, V β, calculate the real-time input power Pi of motor, the calculated value Pt and the real-time input power Pi of motor that compare power input to machine carry out closed-loop control, it is specially adapted to the permanent Boiler pressure control under stable state, precision is high, and cost is low; 2) permanent wind amount of the present invention directly controls power input to a machine, power input to machine is electric variable, measurement is easy and accurate, power input to machine can pass through the higher DC bus-bar voltage of precision, DC bus current or phase current obtain, the stable state that direct Power Control is applicable to system controls, and Boiler pressure control itself is a typical stable state control problem, and therefore both couplings get up to make system more accurately with stable.Direct Power Control is by motor speed control realization, and accurately high, cost is low; 3) the real-time input power Pi of motor adopts wave digital lowpass filter to process, and computational accuracy is higher, and cost is lower.

Accompanying drawing illustrates:

Fig. 1 is the structural representation of traditional air conditioner draught fan system;

Fig. 2 is the scheme of installation of PM motor of the present invention;

Fig. 3 is the stereogram of PM motor of the present invention;

Fig. 4 is the stereogram of the electric machine controller of PM motor of the present invention;

Fig. 5 is the sectional view of PM motor of the present invention;

Fig. 6 is a kind of implementing circuit block diagram of the electric machine controller of the embodiment of the present invention one PM motor;

Fig. 7 is the circuit diagram that Fig. 6 is corresponding;

Fig. 8 is the control flow chart of the constant air capacity control of the embodiment of the present invention one;

Fig. 9 is that the present invention records to obtain gang's permanent wind amount matched curve by experiment;

Figure 10 is the fitting experimental data curve map of the PM motor direct Power Control permanent wind amount of 1/3HP of the present invention;

Figure 11 is that the present invention utilizes interpolation method to solve input air quantity fitting experimental data curve map arbitrarily

Figure 12 is the control logic figure of the constant air capacity control of the embodiment of the present invention one;

Figure 13 is a kind of control procedure schematic diagram of the constant air capacity control of the embodiment of the present invention one;

Figure 14 is the another kind of control procedure schematic diagram of the constant air capacity control of the embodiment of the present invention one;

Figure 15 is the test result figure through experimental verification of the constant air capacity control of the embodiment of the present invention one;

Figure 16 is a kind of implementing circuit block diagram of the electric machine controller of the PM motor of the embodiment of the present invention two;

Figure 17 is the circuit diagram that Figure 12 is corresponding;

Figure 18 is the schematic diagram of a traditional typical PM motor vector controlled;

Figure 19 is each coordinate system graph of a relation of a traditional typical PM motor vector controlled;

Figure 20 is the control logic figure of the constant air capacity control of the embodiment of the present invention two;

Detailed description of the invention:

Below by specific embodiment, also the present invention is described in further detail by reference to the accompanying drawings.

The present invention is as shown in Figure 1, in a typical ventilating duct for air-conditioner, a blower system (as gas furnace or air processing machine) has been installed, replace with " motor+wind wheel " in figure, air cleaner is also had in pipeline, air blast is started during electric motor starting, because air outlet is relevant with room number with the quantity of air intake vent, the standard that the design of pipeline is ununified yet, filter also may have different pressure drops simultaneously, causing carrying traditional load motor---the blower system of PSC motor is in different pipelines, and actual air quantity can be different.As shown in Figure 2,1) control of product is a HVAC controller, and HVAC controller controls all product operation devices and is sent to PM electric machine controller by the peripheral circuit of the interface of a customization and agreement configuration information.2) electric machine controller comprises a microprocessor---and single-chip microcomputer or DSP electron plate do Electric Machine Control, and it has a power unit to provide electric power to controller each several part circuit, and power supply arranges a DC bus-bar voltage and electric current.Therefore, the control of motor will carry out power delivery.The electric machine controller of low cost and batch production adopts parallel resistive circuit as electric current and voltage sensor hardware usually, feedback as system controls motor and drives actuating motor to control, such as vector controlled, Direct Torque Control, and the sensor of other types or sensorless strategy.As everyone knows, the change of any electronic building brick runtime, these changes affect accuracy of detection and persistent reason.3) PM rotor there are magnet body and structure, in stator side or groove, have polyphase windings.When the temperature is changed, permanent magnet and winding resistance can change, and this may cause the change that Electric Machine Control is different.Motor manufacturing process produces also change to a certain degree usually, motor aging, new motor and old motor, the accuracy of the factor controlling of contribution and persistence, in the time etc. of life, can due to variations in temperature from the magnetic flux of the motor of magnet, and demagnetization etc.In addition, the possible risk that motor shaft lost efficacy, the security of system, and will detect or monitor in real time.4) air blast: air blast is arranged on motor shaft, rotates the air-flow of generation with certain speed.The position of installing may affect operation, increases friction, low discharge, or even the direction of rotation of mistake.5) filter: filter should regularly replace and maintenance service.But this may be lose the tracking in a very long time.This will increase frictional influence stream pressure.6) pipe control: pipe-line system may change due to dust and pipeline breaking, the reason of Region control and the change of ON/OFF wind port system pressure.If do permanent Boiler pressure control according to actual conditions above can produce a lot of unstable factor.

As Fig. 3, Fig. 4, shown in Fig. 5, PM motor is usually by electric machine controller 2 and motor monomer 1, described motor monomer 1 comprises stator module 12, rotor assembly 13 and case component 11, stator module 13 is arranged on case component 11, motor monomer 1 is provided with the Hall element 14 of detection rotor position, rotor assembly 13 is sleeved on inner side or the outside composition of stator module 12, the control circuit board 21 that electric machine controller 2 comprises control box 22 and is arranged on inside control box 22, control circuit board 21 generally comprises power circuit, microprocessor, bus current testing circuit, inverter circuit and rotor position measurement circuit 14(and Hall element), power circuit is that each several part circuit is powered, rotor position measurement electric circuit inspection rotor-position signal is also input to microprocessor, the bus circuit of detection is input to microprocessor by bus current testing circuit, DC bus-bar voltage is input to microprocessor by busbar voltage testing circuit, Microprocessor S3C44B0X inverter circuit, inverter circuit controls the power on/off of each phase coil winding of stator module 12.

Embodiment one:

As shown in Figure 6, Figure 7, suppose that PM motor is 3 phase brushless direct current permanent magnetic synchronous motors, rotor position measurement circuit 14 generally adopts 3 Hall elements, 3 Hall elements detect the rotor-position in 360 degree of electrical angle cycles respectively, often turn over the energising that 120 degree of electrical angles change each phase coil winding of a stator module 12, form 3 phase 6 step control models.Exchange input (AC INPUT) to pass through by diode D7, D8, D9, after the full-wave rectifying circuit of D10 composition, DC bus-bar voltage Vbus is exported in one end of electric capacity C1, DC bus-bar voltage Vbus is relevant with input ac voltage, exchange input (AC INPUT) voltage determine after, the line voltage U P of 3 phase windings is PWM copped wave output voltages, UP=Vbus*w, w is the dutycycle that microprocessor is input to the pwm signal of inverter circuit, change line voltage U P and can change DC bus current Ibus, inverter circuit is by electronic switching tube Q1, Q2, Q3, Q4, Q5, Q6 forms, electronic switching tube Q1, Q2, Q3, Q4, Q5, the 6 road pwm signal (P1 that the control end of Q6 is exported by microprocessor respectively, P2, P3, P4, P5, P6) control, inverter circuit also contact resistance R1 for detecting bus current Ibus, bus current testing circuit is sent to microprocessor after being changed by the detection bus current Ibus of resistance R1.Power input to machine controls to be controlled by electronic switching tube Q7, and 1 road pwm signal--the i.e. P0 that microprocessor exports controls the ON time of electronic switching tube Q7, to control power input to machine.

As shown in Figure 8, the constant air capacity control of the PM motor direct Power Control in HVAC system, described PM motor drives wind wheel and has stator module, permanent magnet rotor component and electric machine controller, described electric machine controller comprises microprocessor, inverter circuit, rotor position measurement circuit, bus current testing circuit, busbar voltage testing circuit and power input to machine control circuit (not shown in FIG.), rotor position measurement electric circuit inspection rotor-position signal is also input to microprocessor, microprocessor calculates the real-time rotate speed n of motor according to rotor-position signal, bus current is input to microprocessor by bus current testing circuit, DC bus-bar voltage is input to microprocessor by busbar voltage testing circuit, Microprocessor S3C44B0X inverter circuit, inverter circuit controls the power on/off of each phase coil winding of stator module, Microprocessor S3C44B0X power input to machine control circuit, it is characterized in that: it comprises the steps:

Steps A) actuating motor controller, the target air volume value IN-CFM receiving or preset;

Step B) obtain corresponding function P=f (n) according to target air volume value IN-CFM, wherein n is rotating speed, and P is power input to a machine;

Step C) enter direct Power Control permanent wind amount control model: starter motor when control motor or motor speed are zero, makes it arrive a stable operating point (p along the control track of function P=f (n) _t, n _t); p _t, n _tbe be positioned at meet permanent wind amount control function P=f (n) track on a pair input power and rotating speed;

Step D) keep direct Power Control permanent wind amount control model: calculate the real-time input power Pi of motor according to motor operating parameter; Calculate Δ P=|Pt-Pi|;

Step e) if power increment value Δ P is less than setting value P _set, keep work on hand point;

Step F) if power increment value Δ P is more than or equal to setting value P _set; Whether the operating time of computational speed ring reaches by power/rotating speed control logic; If the operating time of speed ring does not reach, keep work on hand point;

Step G) if the operating time of speed ring reaches, admission velocity control loop presses Δ n=|ni-nt| governing speed, and ni is real-time rotate speed, realize the new operating point (Pi, ni) on track, even Pt=Pi, nt=ni, get back to step C.

Function P=f (n) described above described above obtains like this: first gather initial data, for several target air volume, be adjusted to high static pressure from low static pressure always, this static pressure wants the actual static pressure scope that can contain application, in the process of regulating static, motor is allowed to be in constant speed control, and by regulating motor speed n and the real-time input power Pi of motor to keep air quantity to be target air volume, and record motor steady-state speed the n now and real-time input power Pi of motor of correspondence, like this, for several target air volume, all create one group of rotating speed n and the real-time input power Pi of motor, then corresponding function P=f (n) of each target air volume in several target air volume is produced by the method for curve.

If outside input target air volume value IN-CFM described above is not equal to several target air volume of said determination one of them, can pass through interpolation method, the Fitting Calculation inputs corresponding function P=f (n) of target air volume value IN-CFM with any outside.Achieve the permanent Boiler pressure control of omnidistance arbitrary target air quantity.

Functional relation P=f (n) described above is polynomial function a: P=C ₁+ C ₂× n+...+C _m× n ^m-1, wherein C ₁, C ₂..., C _mbe coefficient, n is motor speed value, the corresponding one group of C of each target air volume ₁, C ₂..., C _mcoefficient also stores, and microprocessor obtains one group of corresponding C according to the target air volume value IN-CFM of input by look-up table or interpolation method ₁, C ₂..., C _mcoefficient, thus obtain functional relation P=f (n).

Stating described functional relation P=f (n) is second order function a: P=C ₁+ C ₂× n+C ₃× n ².

Control method (the Direct P Control for ConstantAirflow Control Apparatus Method) exploitation of direct Power Control permanent wind amount of the present invention and Mathematical Models are such: in general, a ventilating system, the stream air that blower fan is produced a stable state by the motor-driven driving of PM.Constant Boiler pressure control, by speed, power control realization under a static pressure condition, is shown in following relational expression: CFM=F (P, speed, pressure), wherein CFM is air quantity, and P is power, speed is speed, and pressure is static pressure.When the change of static pressure, maintain this permanent wind amount with the control of power and speed.Along with static pressure increases, power and speed change thereupon.Cluster permanent wind amount CFM curve can test out, as shown in Figure 9.Based on these permanent wind amount CFM curve, exploitation Controlling model, when the requirement of control of product determination air quantity, provides a constant wind quantity CFM by control power and speed at specific static pressure.In fig .9, characteristic curve represent retentive control power and speed permanent wind amount physical characteristic, in the rated operating range of all motors, to the air-conditioning producer of the air flow system of the design of any type, based on test result and the rate curve of power, can reach a conclusion, a typical quadratic function can perform well in exploitation modeling as the typical function of one, P=C ₁+ C ₂× n+C ₃× n ², by three point to be located (A, B and C) of the person of choosing on curve, the data on the coordinate of its correspondence are (p1, n1), (p2, n2), and (p3, n3) obtains coefficient C1, C2, C3, see following formula:

$F(A,B,C)={\mathrm{\Σ}}_i^m{(\mathrm{Yi}-(C1+C2*n+C3*n^2))}^2,$ By F θ/θ A=0, θ F/ θ B=0, and θ F/ θ C=0, by solving equation, m=3.

The process of curve selects multinomial to describe curve, and polynomial coefficient can be obtained by least square method.P=C can be used in theory ₁+ C ₂× n+C ₃× n ²+ ...+Cm × n ^m-1, in fact select binomial just can meet general needs.Functional relation P=f (n) is second order function a: P=C ₁+ C ₂× n+C ₃× n ², wherein C ₁, C ₂and C ₃be coefficient, n is motor speed value, the corresponding one group of C of any one target air volume in several target air volume of test ₁, C ₂and C ₃coefficient also stores, and microprocessor obtains one group of corresponding C according to the target air volume value IN-CFM of input by look-up table ₁, C ₂and C ₃coefficient, thus obtain functional relation P=f (n), the corresponding one group of C of each target air volume in certain load ₁, C ₂and C ₃shown in coefficient table 1 specific as follows:

Table 1

CFM	C 1	C 2	C 3
				150	0.338	—0.151	0.0458
300	0.4423	—0.2113	0.0765
				450	。。。	。。。	。。。
600	。。。	。。。	。。。
				750	。。。	。。。	。。。
900	。。。	。。。	。。。

Figure 10 is the fitting experimental data curve map of PM motor in the direct Power Control permanent wind amount of the HVAC system of small pipeline of 1/3HP, for a given target airflow, it is the use of founding mathematical models that some typical air quantity CFM of Systematic selection sets up a database as test point.These are typically put and comprise minimum and maximum quantity of wind value, and more additional intermediate points are according to product specification, and typical air quantity CFM has 5 as test point, is respectively 150/300/450/600 and 750CFM.

Table 2 shows an example of test data result.The scope of the rotating speed of motor is from 200 to 1400rpm; The static pressure of system is from 0.1 to 1H ₂o.Keep presetting permanent wind amount CCFM to export, obtain the power input to machine per unit value of a corresponding Figure 10, form a database.

Table 2

Utilize least square method, the quadratic function of the corresponding power of each predetermined CFM air quantity and rotating speed, obtains in the computational methods of a standard: power and the speed in the operating point of any system of a specific static pressure of the definition of these equations.When input setting air quantity IN-CFM presets, electric system defines a function corresponding with it, and the track of its operating point follows function definition.Equation (3) to (7) can be expressed as a normal equation, and C1, C2, C3 are constants.

$\mathrm{Power}\left(150\right)=0.3388{\left(\frac{n}{1000}\right)}^2-0.1551\left(\frac{n}{1000}\right)+0.0458---\left(3\right)$

$\mathrm{Power}\left(300\right)=0.4423{\left(\frac{n}{1000}\right)}^2-0.2113\left(\frac{n}{1000}\right)+0.0765---\left(4\right)$

$\mathrm{Power}\left(450\right)=0.3987{\left(\frac{n}{1000}\right)}^2-0.0308\left(\frac{n}{1000}\right)+0.0294---\left(5\right)$

$\mathrm{Power}\left(600\right)=0.2580{\left(\frac{n}{1000}\right)}^2+0.3983\left(\frac{n}{1000}\right)-0.1379---\left(6\right)$

$\mathrm{Power}\left(750\right)=0.1385{\left(\frac{n}{1000}\right)}^2+0.8150\left(\frac{n}{1000}\right)-0.3139---\left(7\right)$

Namely P=C is obtained ₁+ C ₂× n+C ₃× n ², equation (3) to (7) modeling curve provides the track of 5 selection operating points of several permanent wind amount CFM demand, and Power is power, and n is rotating speed.

As shown in figure 11, if request permanent wind amount IN-CFM require be not modeling curve one of them, use a kind of interpolation method to obtain the permanent wind amount IN-CFM of new this request of characteristic equation matching, such as when the permanent wind amount IN-CFM=525cfm of request requires received, adjacent two curve C FM1-600cfm and CFM2-450cfm modeling can identify.So latter two corresponding equation may be used for the new equation calculating IN-CFM=525cfm curve.Need-based IN-CFM=525cfm, three selected speed omega 1, ω 2, ω 3, determine to calculate performance number at these speedometers, utilize the speed that the equation that these two model curves are corresponding is being selected for two power points, linear weighted function interpolation can be used for calculating P value. first list matrix data as follows.

$\left[\begin{array}{c}{P}_i\\ P_1\left(600\right)\\ P_2\left(450\right)\end{array}\right]=\left[\begin{array}{ccc}{\mathrm{\ω}}_1& {\mathrm{\ω}}_2& {\mathrm{\ω}}_3\\ P_{11}& P_{12}& P_{13}\\ P_{21}& P_{22}& P_{23}\end{array}\right]$

For a pair power points (p _1i,p _2i) a corresponding selected speed omega, the corresponding 3 couples of power points (p of selected speed omega 1, ω 2, ω 3 _1i, _p2i), linear weighted function interpolation can be used for calculating Pi value and be

pi=p _2i+w.(p _1i-p _2i)。

Weighted value W calculates like this:

Note this CFM2≤IN-CFM≤CFM1, wait 0≤W≤1.Matrix equation is below computable,

$\left[\begin{array}{ccc}{\mathrm{\ω}}_1^2& {\mathrm{\ω}}_1& 1\\ {\mathrm{\ω}}_2^2& {\mathrm{\ω}}_2& 1\\ {\mathrm{\ω}}_3^2& {\mathrm{\ω}}_3& 1\end{array}\right]\left[\begin{array}{c}{C}_1\\ C_2\\ C_3\end{array}\right]=\left[\begin{array}{c}{P}_1\\ P_2\\ P_3\end{array}\right]$

The function P=C of the IN-CFM=525cfm of such correspondence ₁+ C ₂× n+C ₃× n ²can be obtained.Solve this matrix equation, can calculate C1, C2, C3 coefficient.Therefore, any demand input air quantity IN-CFM can obtain power equation.Because the microprocessor that this process is inside electric machine controller---single-chip microcomputer has initialized, so the calculating of power does not need to consume more real-time cpu resource.

The real-time input power Pi of motor adopts wave digital lowpass filter to process: the application of the filtering technique of infinite impulse response filter, supposes that input and output sampling is within the sampling period (PWM switching frequency).The sequence of power input represents (P _in1... P _ini, P _inn) and the sequence of power stage represent (Pout1 ... Pouti ..., Poutn), corresponding to same time point, then low pass filter can be considered as:

$p_{\mathrm{ini}-}{p}_{\mathrm{outi}}=T\frac{p_{\mathrm{outi}}-p_{\mathrm{outi}-1}}{\mathrm{\Δt}}$ Wherein T: time constant;

After above clause, again give recurrence relation, discrete time, low pass filter can be expressed as exponentially weighted moving average (EWMA).

p _outi=a·p _ini+（1-a）·p _outi-1

Wherein

$a=\frac{\mathrm{\Δt}}{T+\mathrm{\Δt}}$

According to definition, smoothing factor 0≤α≤1.If α=0.5, so time constant equals the sampling period.If α < < 0.5, so time constant shows to be greater than the sampling interval.

$T=\mathrm{\&Delta;t}\left(\frac{1-a}{a}\right)$

Electric filtering controls at DPC, a≤0.01.So Δ t=a T.

From a wave filter output to next change be before output and input between difference proportional,

The ratio of this flatness exponential damping is at continuous time system.As expected, along with the continuous increase of time, discrete time smoothing factor α reduces, and the sequence of power stage represent (Pout1 ... Pouti ..., Poutn) and react slow, represent (P in the sequence of power input _in1... P _ini, P _inn) therefore system there is higher inertia.

This filtering technique also can be applied to DC bus-bar voltage, and two signal transacting of DC bus current calculate.

Can find out, this direct Power Control DPC(Direct Power Control) use rotating speed to control to realize power control.The function of power/rotating speed control logic is that coordinating power/rotating speed loop time constant is to ensure the stability of system.Control can by controlling the accurate control of motor, and direct torque compares.No matter that in scalar or vector controlled, speeds control comparatively direct torque is more effective., improve control accuracy.

DPC controls to be carry out speeds control by the power of uniqueness and fans load speed characteristics.Motor is from zero rotating speed to high rotating speed, and power is also like this from zero to increase.The rotating speed of motor by rising until reach a pair operating point A(power, speed), it is static pressure force, as shown in figure 13, when static pressure increases suddenly, under speed control mode, motor provides more power (or larger moment of torsion) to keep speed, because higher static pressure needs very large power requirement.Power can rise to suddenly higher, and when electric system reaches " B " of a new operating point with identical speed, this algorithm will know that whether this is in constant CFM geometric locus operating point, thus determine a pair power/speed point " C ".But C point is not a stable operating point, due to high-power requirement, then removes " D " point, repeatedly, wait " G " that converge to a new stable operating point, terminate.

In force, we can reduce power swing when changing suddenly, control by using restricted power increment.In fig. 14, delta power can be designated as Δ P in its display.As long as changed power exceedes this power increment Δ P, speeds control will carry out speeds control.In this fashion, all operating points work under corresponding permanent wind amount CFM geometric locus positive and negative bandwidth.Distinguished and admirable control system in static pressure change transient process is stable.

As shown in figure 15, above-mentioned motor direct Power Control constant air capacity control and algorithm are tested on our PM electric machine controller, and all systematic functions meet requirement as shown in figure 15.

Figure 12 is that this algorithm controls the logic diagram of application at PM motor scalar, and input power is by DC bus-bar voltage, and Current calculation obtains. power and rotating speed will be limited in peak power P _max, and rotating speed n _maxwithin.

The real-time input power value Pi of motor is calculated by the DC bus current/voltage of feedback, so mate with power/speed data according to the air quantity IN-CFM of outside input, obtain the calculated value Pt of power input to machine, compare calculated value Pt and the real-time power output Pi of motor of power input to machine, obtain difference power Δ P, difference power Δ P is limited, and avoids difference power Δ P excessive, and regulating power fluctuation is larger.Difference power Δ P is exported by power/speed control logic, and carry out speed ring control, PWM frequency converter carries out rotating speed control.

Embodiment two: the maximum difference of the present embodiment and embodiment one be about: the calculating of the real-time input power Pi of motor, embodiment 1 adopts scalar to control, and namely gathers real-time bus current I _busthe real-time input power P=I of motor is calculated with real-time busbar voltage _bus× V _bus.But the PM motor of the present embodiment adopts the vector controlled without sensor, and the calculating of the real-time input power Pi of motor is comparatively complicated.

As shown in Figure 16, Figure 17, suppose that PM motor is 3 phase brushless direct current permanent magnetic synchronous motors of the vector controlled based on no-rotor position sensor, then the phase current of phase current sensing electric circuit inspection stator winding is input to microprocessor, and the flow observer inside microprocessor calculates rotating speed n and the rotor-position of rotor according to the electric current of phase and DC bus-bar voltage.Exchange input (AC INPUT) after the full-wave rectifying circuit be made up of diode D7, D8, D9, D10, export DC bus-bar voltage Vbus in one end of electric capacity C1, DC bus-bar voltage Vbus and input ac voltage about. Figure 18 is the block diagram of a typical vector controlled.

As described in Figure 19, be the coordinate system figure of a typical vector controlled, vector controlled is all documented on textbook and patent document, so there is no need to describe at this.Know the rotating speed of target of control, vector controlled just can be utilized to realize closed-loop control.Have 3 coordinate systems in figure, a fixing cartesian coordinate system (alpha-beta coordinate), one is rotor rotational coordinates (d-q axis coordinate system), and one is stator magnetic flux rotating coordinate system (ds-qs axis coordinate system).In figure, ω represents spinner velocity, and θ is the rotation angle of d-q axis coordinate system and alpha-beta coordinate, and δ is the rotary load angle of d-q axis coordinate system and ds-qs axis coordinate system.Therefore the vector current of d-q axis coordinate system and vector voltage can be converted to electric current and the voltage of alpha-beta coordinate system.

In Figure 16, Figure 17 in vector controlled, motor operating parameter testing circuit comprises phase current sensing circuit and busbar voltage testing circuit, phase current sensing circuit, busbar voltage testing circuit detect phase current and busbar voltage data are input to microprocessor, real-time phase current and real-time busbar voltage V _busand be converted into electric current I α, I β on α β coordinate, voltage V α, V β, motor real-time input power Pi=3/2(I α × V α+I β × V β)

As shown in figure 20, at ensorless control PM electric system, the logic diagram of DPC constant air capacity control. input power is calculated by vector controlled. and this power controls for power after filtering. flux observer estimation rotor speed and rotor-position, so mate with power/speed data according to the air quantity IN-CFM of outside input, function P=f (n) is utilized to be converted into the calculated value Pt of corresponding power input to machine, compare calculated value Pt and the real-time power output Pi of motor of power input to machine, obtain difference power Δ P, difference power Δ P is limited, avoid difference power Δ P excessive, regulating power fluctuation is larger.Difference power Δ P is exported by power/speed control logic, carries out speed ring control, and speed ring controls to be achieved by vector controlled.

Claims (10)

1. The constant air capacity control of 1.PM motor direct Power Control, described PM motor is arranged in HVAC system to drive wind wheel to rotate and to have stator module, permanent magnet rotor component and electric machine controller, described electric machine controller comprises motor operating parameter testing circuit and microprocessor, it is characterized in that: it comprises the steps:

   Steps A) actuating motor controller, the target air volume value IN-CFM receiving or preset;

   Step B) obtain corresponding function P=f (n) according to target air volume value IN-CFM, wherein n is rotating speed, and P is power input to a machine;

   Step C) enter direct Power Control permanent wind amount control model: starter motor when control motor or motor speed are zero, makes it arrive a stable operating point (p along the control track of function P=f (n) _t, n _t); p _t, n _tbe be positioned at meet permanent wind amount control function P=f (n) track on a pair input power and rotating speed;

   Step D) keep direct Power Control permanent wind amount control model: calculate the real-time input power Pi of motor according to motor operating parameter, rated output increment size Δ P=|Pt-Pi|;

   Step e) if power increment value Δ P is less than setting value P _set, keep work on hand point;

   Step F) if power increment value Δ P is more than or equal to setting value P _set, whether the operating time of computational speed ring reaches by power/rotating speed control logic, if the operating time of speed ring does not reach, keeps work on hand point;

   Step G) if the operating time of speed ring reaches, admission velocity control loop presses Δ n=|ni-nt| governing speed, and ni is real-time rotate speed, realize the new operating point (Pi, ni) on track, even Pt=Pi, nt=ni, get back to step C.
2. 2. the constant air capacity control of PM motor direct Power Control according to claim 1, it is characterized in that: motor operating parameter testing circuit comprises bus current testing circuit and busbar voltage testing circuit, bus current testing circuit and busbar voltage testing circuit detect real-time bus current I _buswith real-time busbar voltage V _bus, the real-time input power Pi=I of motor _bus× V _bus.
3. 3. the constant air capacity control of PM motor direct Power Control according to claim 1, it is characterized in that: motor operating parameter testing circuit comprises phase line current testing circuit and busbar voltage testing circuit, phase line current testing circuit, busbar voltage testing circuit detect phase current and busbar voltage data are input to microprocessor, real-time phase current and real-time busbar voltage V _busand convert electric current I α, I β on alpha-beta coordinate, voltage V α, V β to, motor real-time input power Pi=3/2(I α V α+I β V β).
4. 4. the constant air capacity control of the PM motor direct Power Control according to claim 1 or 2 or 3, it is characterized in that: function P=f (n) described above obtains like this: first gather initial data, for several target air volume, be adjusted to high static pressure from low static pressure always, this static pressure wants the actual static pressure scope that can contain application, in the process of regulating static, allow motor be in rotating speed control, and by regulating motor speed n and the real-time input power Pi of motor to keep air quantity to be target air volume, and record motor steady-state speed the n now and real-time input power Pi of motor of correspondence, like this, for several target air volume, all create one group of rotating speed n and the real-time input power Pi of motor, then corresponding function P=f (n) of each target air volume in several target air volume is produced by the method for curve.
5. 5. the constant air capacity control of PM motor direct Power Control according to claim 4, it is characterized in that: if outside input target air volume value IN-CFM is not equal to several target air volume of said determination one of them, interpolation method can be passed through, the Fitting Calculation inputs corresponding function P=f (n) of target air volume value IN-CFM with any outside, achieves the permanent Boiler pressure control of omnidistance arbitrary target air quantity.
6. 6. the constant air capacity control of PM motor direct Power Control according to claim 2, is characterized in that: the real-time input power Pi of motor adopts wave digital lowpass filter to process, to real-time bus current I _bus, real-time busbar voltage V _busdata acquisition time, adopt wave digital lowpass filter process.
7. 7. the constant air capacity control of PM motor direct Power Control according to claim 4, is characterized in that: functional relation P=f (n) described above is polynomial function a: P=C ₁+ C ₂× n+...+C _m× n ^m-1, wherein C ₁, C ₂..., C _mbe coefficient, n is motor speed value, the corresponding one group of C of each target air volume ₁, C ₂..., C _mcoefficient also stores, and microprocessor obtains one group of corresponding C according to the target air volume value IN-CFM of input by look-up table or interpolation method ₁, C ₂..., C _mcoefficient, thus obtain functional relation P=f (n).
8. 8. the constant air capacity control of PM motor direct Power Control according to claim 7, is characterized in that: functional relation P=f (n) is second order function a: P=C ₁+ C ₂× n+C ₃× n ².
9. 9. the HVAC system of the constant air capacity control of PM motor direct Power Control described in an application rights requirement 1 to 8, comprise PM motor and wind wheel, PM motor drives wind wheel rotate and have stator module, permanent magnet rotor component and electric machine controller, and PM motor realizes permanent Boiler pressure control by direct Power Control.
10. 10. the variable speed electric motors, particularly system of the constant air capacity control of PM motor direct Power Control described in an application rights requirement 1 to 8, comprise variable speed electric motors, particularly and wind wheel, variable speed electric motors, particularly drives wind wheel rotate and have stator module, rotor assembly and electric machine controller, and variable speed electric motors, particularly realizes permanent Boiler pressure control by direct Power Control.