CN1976215A - Audible noise reduction for single current shunt platform - Google Patents

Abstract

A method and system for reducing audible motor noise in a system for reconstructing motor phase current from a DC bus current comprising current pulses on a DC bus, and for controlling the motor, which forms a command voltage vector according to a space vector modulation arrangement for controlling the motor; measures the DC bus current; and determines across part area when the command voltage vector results in an inverter switching state that prevents the measuring of the DC bus current from accurately indicating motor phase current. During said inverter switching state, a current sampling scheduler applies a minimum pulse width constraint to said current pulses in said DC bus current to improve reconstruction of said motor phase current based on said DC bus current; and reduces the application of said minimum pulse width constraint to less than once per PWM cycle imposed by the PWM inverter motor drive system, thereby allowing motor phase current reconstruction with reduced audible motor noise. The current sampling scheduler synchronously samples said measured motor phase current to reduce errors; reduces a bandwidth of said motor controller during said inverter switching state; and is adjustable in response to motor speed for setting the number of said minimum pulse width constraints per PWM cycle.

Description

The acoustic noise of single current shunt platform reduces

The cross reference of related application

[0001] the application based on and required to submit on October 26th, 2005 (IR-3076 PROV), sequence number is No.60/730,342 U.S. Provisional Application and the sequence number of submitting on October 25th, 2006 (IR-3076 (2-5385)) are No.11/552, the priority of 758 U.S. Patent application, its content is incorporated herein by reference.

[0002] to relate to open day be United States Patent (USP) 7,102,327 and female case thereof in September in 2006 (IR-2465CIP) on the 5th to the application, and the applying date is that the U.S. in March in 2003 (IR-2160) on the 27th does not authorize application sequence No.10/402,107, in the lump as a reference.

Background technology

1. invention field

[0003] the application relates to a kind of algorithm and system, can drive single current shunt (current shunt) feedback topology by traditional PWM inverter, reduces the acoustic noise of motor.

[0004]

2. correlation technique

[0005] accompanying drawing 1a has shown the three dimensional vector diagram of 2 grades of inverters.In order to realize that direct current connects electric current and allows reliable current sample, when voltage vector enters the shadow region (cross section) of accompanying drawing 1a, has to apply minimum pulse width constraint (accompanying drawing 1b).The embodiment of these technology is at above-mentioned United States Patent (USP) 7,102,327; Sequence number is No.10/402,107; " discussion and the final solution of single current sensor technology in the DC of three-phase PWM-VS inverter is connected " (the SingleCurrent Sensor Technique in the DC-link of Three-phase PWM-VSInverters-A Review and the Ultimate Solution) that delivers in IEEE 1192-1202 page or leaf (1996) with Blaabjerg etc. is described, its full content does not further describe at this in the lump as a reference.

[0006] in 2 grades of inverter systems, the transient current waveform during direct current connects is made up of current impulse.When the index of modulation (motor speed) reduced, current pulse width reduced, up to applying minimum pulse width constraint (by the hardware decision, being typically 0.5-2 μ sec) to obtain reliable current feedback data.As the result who applies this minimum pulse width constraint, current harmonics has increased.Noise of motor wave band acoustically also can increase and propagate, especially when motor low cruise (be lower than rated speed 20 percent), and the longer scope of deriving in the shadow region of the voltage vector among the accompanying drawing 1a wherein.This has caused unacceptable in some applications noise.

Summary of the invention

[0007] the present invention solves the problems referred to above by a kind of algorithm and system are provided, and it reduces the sense of hearing noise of motor that is caused by the single current shunt feedback topology of using conventional P WM inverter to drive.

[0008] sense of hearing noise of motor minimizing technology comprises that adaptability reduces the sum that is applied in the minimum pulse width constraint of accompanying drawing 1a shadow region.This realizes by insert the new program of introducing to minimum pulse.When voltage vector entered the intersection region, current feedback sample rate and electric machine controller bandwidth were according to the elimination correction of minimum pulse.In case voltage vector leaves the shadow region, normal feedback sample rate and electric machine controller bandwidth are recovered.

[0009] in addition, the new progress and the motor speed of minimum pulse insertion adapt.This realizes by the obtainable controller bandwidth of maximization.Therefore in this adaptive feedback sampled form, the switching frequency of PWM is constant, has kept the characteristic of the harmonic wave that PWM causes.

[0010] other features and advantages of the present invention will become apparent in the description of following embodiments of the invention by the reference accompanying drawing.

Description of drawings

[0011] accompanying drawing 1a is the space vector of voltage plane graph of 2 grades of inverters.

[0012] the accompanying drawing 1b sequential chart of minimum pulse width constraint applies that has been illustration.

[0013] accompanying drawing 2 is calcspars of the inverter drive system used of the present invention.

[0014] accompanying drawing 3 (a) is the calcspar of the current sample progress in the accompanying drawing 2; And

[0015] accompanying drawing 3 (b) and 3 (c) are the sequential charts that minimum pulse width constraint in the exemplary embodiment reduces.

Embodiment

[0016] accompanying drawing 2 has shown no transducer inversion device drive system, comprises electric machine controller (speed and Current Control) 10,20,2 grades of inverters 30 of space vector PWM modulator and motor 40.Current of electric (Iw-In, Iv-In) in module 50 by single feedback current Idc in parallel reconstruct.Reconstruct electric current (Iw-In, Iv-In) directly feeds back to electric machine controller usually.But in accompanying drawing 2, these current of electric were handled by current sample progress device 60 before entering electric machine controller.Sense of hearing noise reduces element and is presented in the dashed boxes 70 of accompanying drawing 2.

[0017] in cross section (shadow region of accompanying drawing 1), the single current shunt restructing algorithm is generally each PWM circulation and applies the minimum pulse width clamp.Current sample progress device (Fig. 2) reduces the quantity that the minimum pulse clamp takes place by forcing to apply minimum pulse with the aforementioned speed (UseTmin) that is slower than each PWM circulation.Because the minimizing of minimum pulse clamp can not get direct current and connects electric current and sample rate current (output Iw-In, the Iv-In of single parallel-current reconstruct) demonstration wrong (accompanying drawing 2, the electric current sharp wave Iw-In of bottom trace).These electric current sharp waves (accompanying drawing 2, top trace Iw-R) are suppressed (reject) by current sample progress device 60 synchronized sampling input currents (Iw-In, Iv-In).Inverter PWM frequency reduces in the processing procedure at whole sense of hearing noise and does not change.

[0018] accompanying drawing 3 shows and reduces that the minimum pulse clamp takes place and the details of synchronized sampling in current sample progress device 60.According to the subregional detection of cross part (by PWM space vector modulation device 20), control signal SectorCross (Fig. 2) makes the minimizing of minimum pulse clamp quantity by down counter 62, shown in accompanying drawing 3 (a).Come the value that is carried in this counter (LdCnt) the decision minimum pulse clamp rate of auto-adaptive function 66.

[0019] accompanying drawing 3 (b) has shown an embodiment, applies a minimum pulse in wherein per 4 PWM circulation, and when applying minimum pulse, current of electric (Iw-In, Iv-In) is by S/H circuit 64 (Iw-R, Iv-R) sampling and maintenance.Because motor speed is relatively low, so it is less to introduce error ratio by the electric current that this maintenance causes.

[0020] accompanying drawing 3 (c) illustration apply a minimum pulse in per 8 PWM circulation.

[0021] when the quantity of PWM circulation increases (sample rate minimizing), the electric machine controller bandwidth correspondingly reduces.The information that signal UseCGain and LdCnt provide bandwidth (gain-adjusted) to revise to electric machine controller.High when the UseCGain setting, the controller bandwidth reduces based on value LdCnt.

[0022] when motor speed increases (modulation increases), reduces in subregional consumption average time of cross part.Therefore preload Counter Value (LdCnt) can reduce (L1, L2, L3) and recovers higher controller bandwidth and current sample rate when cross section.In addition, the quantity of preload Counter Value (L1, L2, L3) can increase provides the more gradual change of multi-sampling rate, and the adaptation function 66 of accompanying drawing 3 (a) demonstration can be near curve like this.

Parameter-definition

[0023] Iw-In reconstruct (from single current shunt) w phase current

1.Iv-In reconstruct (from single current shunt) v phase current

2.Iv actual v phase current of electric

3.Iw actual w phase current of electric

4.Iw-R synchronized sampling w phase current

5.Iv-R synchronized sampling v phase current

6.Idc direct current connects electric current

7.LdCnt current sample progress device preload Counter Value

8.SectorCross the signal voltage vector enters the subregional Status Flag of cross part

9.Tmin minimum pulse duration (second)

10.UseCGain controller gain changes controlled flag

11.UseTmin minimum pulse inserts controlled flag

[0024] use IRMCSv2.0 platform driving EBM fan and the performance test of Samsung (Samsung) washing machine to confirm that the noise of the program of proposition reduces ability.

[0025] although described the present invention with reference to certain embodiments, for a person skilled in the art, many other distortion and improvement and other application are conspicuous.Therefore, the present invention is not limited to specific disclosing herein.

Claims (13)

1. one kind is used in the method for reconstruct from system's minimizing sense of hearing noise of motor of the electric machine phase current of DC bus current, described DC bus current comprises the current impulse on the dc bus in the PWM inverter motor drive system with PWM circulation, and be used to control motor, comprising:

According to the space vector modulation layout formation control voltage vector that is used to control motor;

Measurement to inverter power supply with the DC bus current on the dc bus of the described electric machine phase current of reconstruct;

When the control voltage vector causes stoping the DC bus current of measurement accurately to represent the inverter switching states of electric machine phase current, judge the cross section zone;

During described inverter switching states, apply minimum pulse width and be constrained to described current impulse in the described DC bus current, improve reconstruct based on the described electric machine phase current of described DC bus current;

During described cross section zone, apply described minimum pulse width constraint in each PWM circulation less than once, allow to have the motor phase current reconstruction that reduces sense of hearing noise of motor thus.

2. method according to claim 1 further comprises the described electric machine phase current that measures of synchronized sampling, is suppressed at during the cross section error of the electric machine phase current that measures that the described minimizing by described minimum pulse constraint causes.

3. method according to claim 2 further comprises according to described sampling and to reduce the bandwidth of described electric machine controller in the subregional minimizing of cross part.

4, method according to claim 1 further comprises according to described sampling and to reduce the bandwidth of described electric machine controller in the subregional minimizing of cross part.

5, method according to claim 1, wherein said current sample progress device is regulated in response to motor speed, to be used for reducing the quantity of using at the described minimum pulse width in cross section zone.

6, method according to claim 5 is wherein reducing step, and the minimizing that the described minimum pulse width when low motor speed is used is greater than at higher motor speed the time.

7, a kind of space vector PWM motor driven systems, the noise with method operation according to claim 1 reduces the progress device.

8, a kind of PWM inverter motor drive system that is used to control the motor with the minimizing of sense of hearing noise of motor comprises:

Electric machine controller has the PWM circulation and arranges formation control voltage vector according to the space vector modulation that is applied to motor;

Be used to measure the unit of DC bus current, described DC bus current is included in the current impulse on the dc bus that supplies power to the electric machine phase current that inverter and reconstruct wherein forms;

Described electric machine controller when the control voltage vector causes stoping the DC bus current of measurement accurately to represent the inverter switching states of electric machine phase current, is judged the cross section zone;

During described inverter switching states, current sample progress device retrains the described current impulse that is applied in described DC bus current with minimum pulse width, to improve the reconstruct based on the described electric machine phase current of described DC bus current;

Described current sample progress device during described cross section zone, applies described minimum pulse width constraint less than once in each PWM circulation, allow to have the motor phase current reconstruction that reduces sense of hearing noise of motor thus.

9, system according to claim 8, the described electric machine phase current that measures of wherein said current sample progress device synchronized sampling is suppressed at during the cross section error of the electric machine phase current that measures that the described minimizing by described minimum pulse constraint causes.

10, system according to claim 9, wherein said current sample progress device reduces the bandwidth of described electric machine controller according to the minimizing of the described sampling in described cross section zone.

11, system according to claim 8, wherein said current sample progress device reduces the bandwidth of described electric machine controller according to the minimizing of the described sampling in described cross section zone.

12, system according to claim 8, wherein said current sample progress device is regulated in response to motor speed, to be used for reducing the quantity of using at the described minimum pulse width in cross section zone.

13, system according to claim 12, wherein the minimizing of using of the described minimum pulse width when low motor speed is greater than at higher motor speed the time.