Air volume compensation method for range hood

Abstract

The application discloses a wind volume compensation method of an extractor hood, and the extractor hood comprises a fan system and a power board, wherein the fan system comprises a motor, and the power board comprises a main control chip and a driving chip used for driving the motor; the wind volume compensation method comprises the following steps: S1, acquiring a current parameter value of the motor; S2, before the motor starts, the main control chip replaces an initial parameter value of the motor with the current parameter of the motor acquired in the step S1; S3, the main control chip substitutes the current parameter of the motor into wind volume calculation, performs online wind volume calculation, controls the rotating speed of the motor according to the calculation result through the driving chip, and realizes compensation correction of the wind volume.

Description

TECHNICAL FIELD

[0001] The present application relates to an oil fume purification device, in particular to a wind volume compensation method of an extractor hood. BACKGROUND

[0002] The extractor hood has become one of the indispensable kitchen household appliances in modern families. The extractor hood works by using the principle of fluid dynamics, and absorbs and discharges the oil fume by using the fan system installed in the extractor hood and filtering some oil particles by using the filter screen. The fan system is usually a centrifugal fan, which includes a volute, an impeller installed in the volute, and a motor driving the impeller to rotate. When the impeller rotates, a negative pressure suction force is generated at the center of the fan, which sucks the oil fume below the extractor hood into the fan, and the oil fume is collected and guided by the volute after being accelerated by the fan and then discharged outdoors.

[0003] Generally, different floors and different numbers of extractor hoods used at the same time can cause different pressures of the public flue, and therefore a stable wind volume is needed to ensure good smoke exhaust effect. The traditional extractor hood cannot automatically adjust the exhaust capacity according to the change of the wind pressure, but can only be adjusted by changing the gear.

[0004] A common solution at present is that the fan system adopts a three-phase variable frequency motor, which adjusts the motor speed according to the difference between the actual speed and the set speed of the current gear, so as to stabilize the motor speed at the set value and compensate for the loss of wind volume. Alternatively, the running parameters and the parameters of the motor itself, including the speed, are monitored to compensate for the wind volume, as disclosed in the Chinese patent with the application number 201410073417.0.

[0005] However, the commonly used motor parameters, such as resistance, inductance and back electromotive force constant, often change with the temperature change of the motor body. As the cumulative running time of the motor increases, the motor generates more and more heat, the motor parameters deviate, and therefore the physical real model of the motor cannot correspond to the theoretical model, causing the control precision and the performance of the whole machine to change, and in severe cases, the motor cannot run.

[0006] The existing technical solutions generally use motor offline / on-line parameter identification to ensure that the physical model of the motor corresponds to the theoretical model. Offline motor parameter identification refers to identifying the motor parameters before the motor starts or in the static state, and on-line parameter identification calculates the motor parameters in the current state in real time and updates the motor parameter values in real time. The main problem of offline motor identification is that it has a lag and cannot accurately calculate the current motor parameters. In addition, offline identification requires the motor to be in a completely static state, which inevitably causes a delay in starting the motor. The on-line motor identification estimates the current motor parameters in the running state of the motor, and the current running signal value of the motor is easily superimposed on the calculation model, so that the estimation accuracy cannot be guaranteed, and the error is generally about 20%. SUMMARY

[0007] The technical problem solved by the present application is to provide a wind volume compensation method for an extractor hood to improve motor parameter accuracy and realize real-time compensation correction of wind volume.

[0008] The technical solution adopted by the present application to solve the above technical problem is as follows: a wind volume compensation method for an extractor hood, the extractor hood comprising:

[0009] a fan system comprising a motor; and

[0010] a power board comprising a master control chip and a driving chip for driving the motor; characterized in that the wind volume compensation method comprises the following steps:

[0011] S1, obtaining a current parameter value of the motor;

[0012] 1) Initial power-on of the extractor hood: the master control chip obtains information about whether the extractor hood is provided with a smoke baffle and initial parameter values of the motor;

[0013] 2) Determining motor parameter identification logic according to the type of the smoke baffle:

[0014] 2.1) The whole machine has a smoke baffle: the master control chip sends an instruction for offline identification of parameters of the motor, and the driving chip executes an offline identification program, and then enters step 2.3);

[0015] 2.2) The whole machine does not have a smoke baffle: the master control chip determines whether to perform offline identification of motor parameters according to the cumulative running time and downtime of the motor, if yes, enters step 2.3) after the driving chip executes the offline identification program, if no, makes the current motor parameters the motor parameters updated last time, and then enters step S2;

[0016] 2.3) After the master control chip issues the offline identification instruction, after receiving the latest motor parameters sent by the driving chip, the latest motor parameters are stored, and the motor parameters updated last time are made as the latest motor parameters;

[0017] 2.4) Detecting the current downtime t stop , if t stop > t max , making the current parameter value of the motor the initial parameter value of the motor; if t stop ≤ t max , making the current parameter value of the motor the latest motor parameters; wherein t max is a preset upper limit value of the cooling time for the motor parameters to return to the initial value;

[0018] S2, before the motor starts, the master control chip replaces the initial parameter value of the motor with the current parameter of the motor obtained in step S1;

[0019] S3, the master control chip substitutes the current parameter of the motor into the wind volume calculation to perform online wind volume calculation, and controls the speed of the motor through the driving chip according to the calculation result to realize compensation correction of the wind volume.

[0020] The presence or absence of the baffle of the range hood is combined with the offline identification of the motor parameter, the influence of the baffle on the oil fume suction effect and the influence on the fan system are considered, the accuracy of the motor parameter is improved, the result of the offline identification of the motor parameter is updated in real time according to the presence or absence of the offline identification, and the online compensation correction of the wind volume is realized through the offline motor parameter identification method.

[0021] Preferably, in step 2.2), the following steps are implemented:

[0022] 2.2.1) the master control chip records the cumulative running time t of the motor run If t run ≤ T runtime , step 2.2.2) is entered, and if t run > T runtime , step 2.2.3) is entered; T runtime is a preset lower limit value of the cumulative running time of the motor in which the motor parameter deviates, and t max > T runtime .

[0023] 2.2.2) the master control chip does not send an offline identification instruction to the driving chip, and the current parameter of the motor is the motor parameter updated last time;

[0024] 2.2.3) when the master control chip receives a shutdown instruction of the motor, the shutdown time t of the motor is detected stop If t stop > t-Δt, the master control chip sends an offline identification instruction to the driving chip once, and then step 2.3) is entered; if t stop ≤ t-Δt, the master control chip does not send an offline identification instruction to the driving chip, and the current parameter of the motor is the motor parameter updated last time, and then step S2 is entered; wherein t is a preset power supply time, and Δt is a preset shutdown time difference value.

[0025] Preferably, in the initial power-on of the range hood in step S1, the following steps are included:

[0026] 1.1) the master control chip obtains the movement mechanism information of the baffle;

[0027] 1.2) The main control chip controls the driving chip to maintain power supply within a preset power supply time t;

[0028] 1.3) After power on, the driving chip sends the initial parameter value of the built-in motor to the main control chip;

[0029] 1.4) The main control chip stores the received initial parameter value of the motor and the information of the smoke baffle;

[0030] 1.5) The main control chip detects whether there is a gear instruction for the operation of the fan system, and if not, the power supply of the driving chip is turned off, and the driving chip is in a low-power mode.

[0031] Preferably, in step S1, when the whole machine has a smoke baffle, the following steps are included:

[0032] 2.1.1) The movement mechanism of the smoke baffle performs a complete action, and the action time is t flap If t flap >T cutoff , step 2.1.2) is entered; if t flap <T cutoff , step 2.2) is entered; T cutoff is a preset minimum time value for the movement mechanism to drive the smoke baffle to perform a complete action;

[0033] 2.1.2) After the main control chip receives the shutdown instruction of the motor, it detects the shutdown time t stop of the motor. When t stop exceeds t-Δt, the main control chip sends an offline identification instruction to the motor, and then enters step 2.3); Δt is a preset shutdown time difference value.

[0034] Preferably, in step 2.1.2) or 2.2.3), after the main control chip issues an offline identification instruction, the identified value is a resistance value, including the following steps:

[0035] 1) The driving chip receives an offline identification flag from the main control chip;

[0036] 2) The driving chip performs offline resistance identification and calculates the identified resistance value R new ;

[0037] 3) The driving chip sends R new to the main control chip.

[0038] Preferably, in step 2.3), after the main control chip issues an offline identification instruction, the main control chip receives the latest R new , and R new上 =R newand stored, and then the stop time t of the motor is detected stop , the driving chip power is cut off, and the driving chip is in a low-power mode; in step 2.4), the master control chip detects the stop time t of the motor, and if t stop >t, the driving chip power is cut off, and the driving chip is in a low-power mode; in step 2.4), the master control chip detects the stop time t of the motor, and if t stop >t max , R=R int ; if t stop ≤t max , R=R new ; wherein R new上 is the updated motor resistance parameter value used at a previous time before the motor parameter is updated, R int is the initial motor resistance parameter, and R is the current motor resistance parameter value.

[0039] Preferably, the motor is a motor with U, V and W three phases, and each phase includes upper and lower bridge arms, and the offline resistance identification method includes the following steps:

[0040] 1) Before the motor is started, the six bridge arms are closed;

[0041] 2) the lower bridge arm of the V phase is disconnected, and the upper bridge arm of the U phase is turned on in a PWM mode;

[0042] 2.1) continuously detect the V phase current, and when the current meets the range (A1, A2), wait for the V phase current to stabilize;

[0043] 2.2) after stabilization, measure the current I1 and bus voltage U1, and determine the duty ratio Duty u1 and the dead time ratio Duty D1 of the upper bridge arm of the V phase at this time;

[0044] 2.3) after each data acquisition in steps 2.1) and 2.2), change the duty ratio to continue to increase the V phase current, and when the current meets the range (A3, A4), wait for the V phase current to stabilize;

[0045] 2.4) after stabilization, measure the current I2 and bus voltage U2, and determine the duty ratio Duty u2 and the dead time ratio Duty D2 of the upper bridge arm of the V phase at this time;

[0046] 2.5) the V phase resistance is R1=(U2×(Duty D1 -Duty D2 )-U1×(Duty u1 -Duty u2 ) / (2×(I2-I1));

[0047] 2.6) Close all bridge arms, after the motor internal current is released, exchange the bridge arms, so that the lower bridge arm of W phase is disconnected, the upper bridge arm of V phase is turned on in PWM mode, and the resistance R2 of the W phase is obtained in the same way as V; then continue to exchange the bridge arms, so that the lower bridge arm of U phase is disconnected, the upper bridge arm of W phase is turned on in PWM mode, and the resistance R3 of U phase is obtained in the same way as V;

[0048] 2.7) Calculate (R1+R2+R3) / 3, and the obtained value is the identified resistance value;

[0049] The above A1, A2, A3 and A4 are preset current thresholds, and A3>A1 and A4>A2.

[0050] The problem of inaccurate offline resistance identification precision is solved by measuring the current difference value through twice PWM pulse injection, and the effect of resistance identification within 5% deviation is realized.

[0051] Preferably, the main control chip has an output pin, the driving chip has a power signal input end, the external power input end is reduced by the first switching power chip to supply power to the driving chip, the path between the power signal input ends of the output pins of the main control chip is controlled by a transistor, the base of the transistor is connected to the output pin of the main control chip, the emitter of the transistor is connected to the external power input end, and the collector of the transistor is connected to the first switching power chip.

[0052] Compared with the prior art, the advantages of the present application are that whether the smoke deflector exists or not is combined with whether the motor parameter offline identification exists or not, the influence of the smoke deflector on the smoke absorption effect is considered, then the influence on the fan system is considered, the motor parameter precision is improved, the result of the motor parameter offline identification is updated in real time according to whether the offline identification exists or not, the online compensation correction of the air volume is realized through the offline motor parameter identification method, if there is no fan operation instruction after the preset power supply time, the power supply of the driving chip is cut off, the power consumption is reduced, the constraint that the motor parameter offline identification needs the motor to be completely stationary is solved, and the effect of no delay of the motor start is realized. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 It is a schematic view of an embodiment of the extractor hood of the present application;

[0054] Figure 2 It is a sectional view of Figure 1

[0055] Figure 3 It is a partial schematic view of Figure 1

[0056] Figure 4 ​​Circuit diagram of the motor of the fan system of the range hood according to the embodiment of the present application;

[0057] Figure 5 Schematic diagram of another embodiment of the range hood according to the present application;

[0058] Figure 6 Circuit diagram of the power board and touch / display chip of the range hood according to the embodiment of the present application;

[0059] Figure 7 Control flow chart of the main control chip to the driving chip of the range hood according to the embodiment of the present application;

[0060] Figure 8 Partial circuit diagram of the main control chip and driving chip of the power board of the range hood according to the embodiment of the present application;

[0061] Figure 9 Flow chart of the air volume compensation method of the range hood according to the embodiment of the present application. DETAILED DESCRIPTION

[0062] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals indicate the same or similar elements or elements having the same or similar functions.

[0063] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, since the disclosed embodiments of the present application can be arranged in different directions, so these orientation-indicating terms are only illustrative and should not be regarded as limiting, such as "upper", "lower" do not necessarily be limited to the direction opposite or consistent with the direction of gravity. In addition, the features defined as "first", "second" can explicitly or implicitly include one or more of the features.

[0064] Referring to Figures 1-3An extractor hood comprises a fume collecting cover 1 and a fan system 2, which can be arranged independently in a fan frame 3 or in the fume collecting cover 1. The fume collecting cover 1 is formed with an air inlet 11 on the front side of the fume collecting cover 1, and the extractor hood further comprises a fume baffle 4 capable of opening and closing the air inlet 11 and a movement mechanism 7 for driving the fume baffle 4 to move. The above-mentioned structure can be a side suction type extractor hood. The specific movement mode of the fume baffle 4 and the driving mode of the movement mechanism 7 are not limited, and any structure capable of opening and closing the air inlet 11 by the fume baffle 4 can be used.

[0065] The fan system 2 comprises a volute 21, an impeller 22 arranged in the volute 21, and a motor 23 for driving the impeller 22 to rotate. The motor 23 is a permanent magnet synchronous motor, which is a three-phase motor. Referring to Figure 4 The circuit schematic diagram of the motor 23 comprises three phases U, V and W, and each phase has two bridge arms. The driving chip 512 (to be described below) sends a driving signal to control each phase. The above-mentioned circuit schematic diagram, including the arrangement mode of the three-phase bridge arms and the driving mode of the driving chip 512, is prior art and will not be described here.

[0066] The resistance identification (offline identification) method of such a motor 23 is to calculate the resistance value according to Ohm's law, which comprises the following steps:

[0067] 1) Before the motor 23 starts, the six bridge arms are closed;

[0068] 2) The lower bridge arm V2 of the V phase is disconnected, and the upper bridge arm U1 of the U phase is turned on in PWM mode;

[0069] 2.1) continuously detect the V phase current, and when the current meets the range (A1, A2), wait for it to be stable;

[0070] 2.2) after being stable, measure the current I1 and the bus voltage U1, and determine the duty ratio Duty u1 and the dead time ratio Duty D1 of the upper bridge arm V1 of the V phase at this time;

[0071] 2.3) after obtaining the data in steps 2.1) and 2.2), change the duty ratio to continue to increase the V phase current, and when the current meets the range (A3, A4), wait for it to be stable;

[0072] 2.4) after being stable, measure the current I2 and the bus voltage U2, and determine the duty ratio Duty u2 and the dead time ratio Duty D2 of the upper bridge arm V1 of the V phase at this time;

[0073] 2.5) the V phase resistance is R1=(U2×(DutyD1 Duty D2 )-U1×(Duty u1 Duty u2 )) / (2×(I2-I1));

[0074] 2.6) Close all bridge arms, after the motor internal current is released, exchange the bridge arms, the lower bridge arm W2 of the W phase is disconnected, the upper bridge arm V1 of the V phase is turned on in the PWM mode, and the resistance R2 of the W phase is obtained in the same way as the V phase. Then continue to exchange the bridge arms, the lower bridge arm U2 of the U phase is disconnected, and the upper bridge arm W1 of the W phase is turned on in the PWM mode, and the resistance R3 of the U phase is obtained in the same way as the V phase.

[0075] 2.7) Calculate (R1+R2+R3) / 3, which is the identified resistance value.

[0076] The above A1, A2, A3 and A4 are respectively preset current thresholds, wherein A1 and A2 can be set according to the current estimated value calculated according to the given voltage and the resistance value of the motor, A1 and A2 can be ±10% of the value respectively; A3>A1, A4>A2, preferably A3=2A1, A4=2A2. Optionally, the value range of A1, A2, A3 and A4 is 0.5-2A.

[0077] In addition, the measured current after stabilization is Figure 4 Iabc (the values obtained by two measurements are respectively I1 and I2), and the voltage is Figure 4 Vdc (the values obtained by two measurements are respectively U1 and U2).

[0078] The above identification method solves the problem of inaccurate offline resistance identification precision by measuring the current difference value through two PWM pulse injections, and realizes the effect within 5% deviation of resistance identification.

[0079] The range hood further comprises an electric appliance box 5 comprising a power board 51 for controlling the fan system 2, the smoke baffle 4 or other electric control components not shown.

[0080] Referring to Figure 5 , another form of a range hood is shown, which is usually a top suction type range hood, which is different from Figure 1 and Figure 2 in that the smoke inlet 11 is arranged at the bottom of the smoke collecting hood 1, and the smoke baffle 4 is no longer arranged.

[0081] Of course, in the present application, the range hood can also be in other forms, such as low suction type, ceiling type, etc. The above examples are only to distinguish the range hood with the movable smoke baffle 4 which can be opened and closed, and the range hood with the smoke inlet 11 in the form of always open (without the smoke baffle 4 or the smoke baffle 4 is fixed).

[0082] Referring to Figure 6 , regardless of the form of the range hood, the power board 51 includes a main control chip 511 and a drive chip 512. Among them, the main control chip 511 is mainly used for external load control, which can communicate with the touch / display chip 6 of the display (not shown) provided on the smoke hood 1, the smoke baffle 4 or the fan frame 3, the movement mechanism 7 of the smoke baffle 4 or the lighting device (not shown). The touch keys can be provided on the display, and the working state of the range hood can be displayed and switched. The drive chip 512 is used for the operation control of the motor 23 of the fan system 2, which can communicate with the main control chip 511 in both directions. The main control chip 511 sends a power control signal to the drive chip 512, and the drive chip 512 can send the monitored data (such as the resistance parameter mentioned above) to the main control chip 511.

[0083] Referring to Figure 8 , the output pin of the main control chip 511 outputs a high-low level control signal, which is marked as IN1 here, and the high level is 15V, and 3.3V is the power signal for driving the above-mentioned drive chip 512, which is marked as OUT1 here. The 18V level (marked as IN2 here) input from the external power supply is stepped down to 3.3V by the first switching power supply chip U3 and the second switching power supply chip U4 to supply power to the drive chip 512. The path between IN2 and OUT1 is controlled by the transistor Q1 shown in the figure. The base of the transistor Q1 is connected to the output end of the optocoupler PC1 (which is connected between the transistor Q1 and IN1), the emitter of the transistor Q1 is connected to IN2, and the collector of the transistor Q1 is connected to the first switching power supply chip U3. Once IN1 controls the output high level, the 18V level from the external power supply is stepped down to 3.3V by the first switching power supply chip U3 and the second switching power supply chip U4 to supply power to the drive chip 512; once IN1 controls the output low level, after isolation by the optocoupler PC1, the transistor Q1 is cut off, the path between IN2 and the first switching power supply chip U3 is disconnected, and the 18V power supply is no longer reduced to 3.3V power supply. Therefore, the drive chip 512 has no external power supply and stops working. Thus, the main control chip 511 controls the power supply of the drive chip 512.

[0084] Specifically, when applied to the whole range hood, the above-mentioned main control chip 511 controls the output pin to control the drive chip 512, referring to Figure 7 , including the following steps:

[0085] 1) Once the range hood is normally powered (connected to the mains 220V), the main control chip 511 controls the output pin IN1, outputs high level, normally supplies 15V power;

[0086] 2) Detect whether the range hood needs to execute the fan system 2 operation instruction, if yes, IN1 continuously supplies 15V power, if not, the main control chip 511 starts timing, and after the accumulated time reaches the preset power supply time t (the time is pre-set, which can be set according to the needs, such as 10s can be selected), the 15V power supply is cut off, and the main control chip 511 outputs low level; When the power is cut off, the main control chip 511 and the drive chip 512 are in low power consumption mode (the same as the way of entering low power consumption of the conventional chip with low power consumption mode), which is beneficial to the motor 23 without delay start.

[0087] Therefore, referring to Figure 9 , the air volume compensation method of the range hood of the application comprises the following steps:

[0088] S1, obtain the parameter value of the current motor 23, which is resistance R or inductance; Specifically, it comprises the following steps:

[0089] 1) Initial power-on of the range hood:

[0090] 1.1) The main control chip 511 obtains the information of the smoke baffle movement mechanism 7 (whether there is a smoke baffle, movement time), which can be completed by sending to the main control chip 511 after the display board is powered on;

[0091] 1.2) The main control chip 511 controls the drive chip 512 to maintain power supply within the preset power supply time t;

[0092] 1.3) After power-on, the drive chip 512 sends the built-in motor initial parameter value, such as R int (resistance), L int (inductance), Ke int (back electromotive force coefficient) to the main control chip 511;

[0093] 1.4) The main control chip 511 writes the received motor initial parameter value and smoke baffle information into the storage module of the power board 51, such as EEPROM (not shown), to prevent the range hood from being cleared after power failure;

[0094] 1.5) After successful writing, the main control chip 511 detects whether there is a gear instruction for running the fan system 2, if not, the power supply of the drive chip 512 is cut off, and the power-off mode can be referred to Figure 7 and the corresponding description above and Figure 7 ;

[0095] 2) Determine the motor parameter identification logic according to the type of the smoke baffle:

[0096] 2.1) The entire machine has a smoke baffle:

[0097] 2.1.1) Motion mechanism 7 performs one complete action of opening-closing or closing-opening, with an action time of t. flap , such as t flap >T cutoff Proceed to step 2.1.2); such as t flap <T cutoff If so, proceed according to the logic for a range hood without a baffle plate, and enter step 2.2); T cutoff The minimum time value for the preset motion mechanism 7 to drive the smoke baffle 4 to complete the opening and closing action, optional, T cutoff For example, 10 seconds;

[0098] 2.1.2) After receiving the stop command from motor 23, the main control chip 511, within the stop time t... stop When the time exceeds t-Δt, the main control chip 511 sends an offline identification command to the motor 23, and the drive chip 512 executes the offline identification program (in this embodiment, resistance identification is used as an example for explanation, and the same applies to inductance); Δt is a preset stop time difference, such as 3s; then proceed to step 2.3);

[0099] 2.2) The entire machine lacks a smoke baffle:

[0100] 2.2.1) The main control chip 511 records the cumulative running time t of motor 23. run , such as t run ≤T runtime Proceed to step 2.2.2), such as t run >T runtime Then proceed to step 2.2.3); T runtime The minimum cumulative running time of the motor when the preset motor parameters deviate, such as 30 minutes;

[0101] 2.2.2) The main control chip 511 does not send offline identification commands, and sets R = R new上 Proceed to step S2; where R new上 R is the resistance value of motor 23 after the last update, and R is the current resistance parameter value of motor 23;

[0102] 2.2.3) When the cumulative running time t run >T runtime Then, when the main control chip 511 receives a stop command from motor 23 midway, if the stop time t stop >t-Δt, the main control chip 511 sends an offline identification command to the driver chip 512, and then proceeds to step 2.3); if the downtime t stop≤ t - Δt, the master chip 511 does not send offline identification instruction, and R = R new上 Then, go to step S2;

[0103] 2.3) The master chip 511 updates R:

[0104] After the master chip 511 issues the offline identification instruction, the latest R new is received, and then stored in the storage module, R new上 = R new After that, the downtime t stop of the current motor 23 is detected. stop If t new上 > t, the power supply of the driving chip 512 is cut off; R stop is the updated motor resistance parameter value used at the previous time of motor parameter update.

[0105] 2.4) The master chip 511 detects the downtime t stop of the current motor 23. max If t int > t stop , R = R max is stored in the storage module; if t new ≤ t max , R = R max is stored in the storage module; t runtime is the upper limit value of the cooling time for the motor parameters to return to the initial value, and t int > T new , such as 40 minutes; R new is the initial motor parameter described in step 1.3) above, which can be 7Ω.

[0106] In steps 2.1.2) and 2.2.3) above, when the master chip 511 issues the offline identification instruction, the specific steps include:

[0107] 1) The driving chip 512 receives the offline identification flag from the master chip 511;

[0108] 2) Offline resistance identification is performed according to the motor resistance offline identification method described above, and R new = (R1+R2+R3) / 3 is calculated.

[0109] 3) The driving chip 512 sends R new to the master chip 511 through the serial port.

[0110] S2, before the motor 23 starts, the current parameter (resistance R) of the motor 23 obtained in step S1 is used to replace the default initial parameter of the motor, and the updated parameter can also be stored in the storage module EEPROM (not shown) of the power board 51, and the parameter reading and replacement are completed by the master control chip 511;

[0111] S3, the master control chip 511 substitutes the current parameter (resistance R) of the motor 23 into the wind volume calculation (the change of resistance will cause the change of rotating speed, and there is a certain relationship between the rotating speed and the wind volume, which is known in the art), and performs online wind volume calculation. According to the calculation result, the driving voltage or driving current of the driving chip 512 is controlled, so as to control the rotating speed of the motor 23, and realize the compensation and correction of the wind volume. This way of controlling the rotating speed according to the calculated wind volume is the prior art, which can be referred to in the background art or the prior Chinese patent with application number 201910571732.9 of the applicant. PI self-tuning can also be used to realize accurate control of the wind volume, and the control accuracy is higher.

Claims

1. A method for air volume compensation of a range hood, the range hood comprising: a fan system (2) comprising a motor (23) ; and a power board (51) comprising a main control chip (511) and a driving chip (512) for driving the motor (23) ; the method comprising the following steps: S1, obtaining a current parameter value of the motor (23) ; 1) initial power-on of the range hood: the main control chip (511) obtains information about whether the range hood is provided with a smoke baffle (4) and an initial parameter value of the motor (23) ; 2) determining motor parameter value identification logic according to the type of the smoke baffle: 2.1) the range hood is provided with a smoke baffle: the main control chip (511) sends an instruction for offline identification of the parameter value of the motor (23), the driving chip (512) executes an offline identification program, and then step 2.3) is entered; 2.2) the range hood is not provided with a smoke baffle: the main control chip (511) determines whether to perform offline identification of the parameter value of the motor (23) according to the cumulative running time and downtime of the motor (23), if yes, the driving chip (512) is caused to execute an offline identification program, and then step 2.3) is entered, if no, the current parameter value of the motor (23) is caused to be the last updated parameter value of the motor (23), and then step S2 is entered; 2.3) after the main control chip (511) sends the offline identification instruction, after receiving the latest parameter value of the motor (23) sent by the driving chip (512), the latest parameter value of the motor (23) is stored, and the last updated parameter value of the motor (23) is caused to be the latest parameter value of the motor (23) ; S2, before the motor (23) is started, the main control chip (511) replaces the initial parameter value of the motor (23) with the current parameter value of the motor (23) obtained in step S1; S3, the main control chip (511) substitutes the current parameter value of the motor (23) into air volume calculation, performs online air volume calculation, controls the rotating speed of the motor (23) through the driving chip (512) according to the calculation result, and realizes compensation and correction of the air volume. In step 2.2), the following steps are implemented: 2.2.2) the main control chip (511) does not send an offline identification instruction to the driving chip (512), and the current parameter value of the motor (23) is caused to be the last updated parameter value of the motor (23) ; In the initial power-on of the range hood in step S1, the following steps are included: 1.1) the main control chip (511) obtains information about a movement mechanism (7) of the smoke baffle (4) ; 1.2) the main control chip (511) controls the driving chip (512) to maintain power supply for a preset power supply time t; 1.3) after power-on, the driving chip (512) sends the built-in initial parameter value of the motor to the main control chip (511) ; 1.4) the main control chip (511) stores the received initial parameter value of the motor (23) and the information about the smoke baffle (4). ​ ​ ​ ​ ​ ​ ​ ​ 2.4) detecting the current downtime t stop if t stop > t max , the current parameter value of the motor (23) is the initial parameter value of the motor (23); if t stop ≤ t max , the current parameter value of the motor (23) is the latest parameter value of the motor (23); wherein t max is a preset upper limit value of the cooling time for the parameter value to return to the initial value; ​ ​ 2. The method of air volume compensation for a range hood according to claim 1, wherein: ​ 2.2.1) the master chip (511) records the cumulative running time t of the motor (23) run If t run ≤ T runtime , go to step 2.2.2), if t run > T runtime , go to step 2.2.3); T runtime is the preset lower limit value of the cumulative running time of the motor whose parameter value deviates, and t max > T runtime ; ​ 2.2.3) When the master chip (511) receives the stop command of the motor (23), detect the stop time t of the motor (23) stop If t stop > t-Δt, the master chip (511) sends an offline identification instruction to the drive chip (512), and then enters step 2.3); if t stop ≤ t-Δt, the master chip (511) does not send an offline identification instruction to the drive chip (512), and makes the current parameter value of the motor (23) the last updated motor (23) parameter value, and then enters step S2; wherein t is a preset power supply time, and Δt is a preset stop time difference value.

3. The method of air volume compensation for a range hood according to claim 1, wherein: ​ ​ ​ ​ ​ 1.5) The main control chip (511) detects whether there is a fan system (2) operating gear instruction, if not, the power supply of the drive chip (512) is turned off, and the drive chip (512) is in low power consumption mode.

4. The method of air volume compensation for a range hood according to claim 3, wherein: In step S1, 2.1) when the whole machine has a smoke baffle: Comprising the following steps: 2.1.1) The motion mechanism (7) of the smoke baffle (4) performs one complete action, and the action time is t. flap If t flap >T cutoff Proceed to step 2.1.2); if t flap <T cutoff Then proceed to step 2.2); T cutoff The minimum time value for the preset motion mechanism (7) to drive the smoke baffle (4) to complete one complete action; 2.1.2) After the master chip (511) receives the stop command of the motor (23), it detects the stop time t of the motor (23) stop When t stop When t-Δt is exceeded, the master chip (511) sends an offline identification instruction to the motor (23), and then enters step 2.3); Δt is a preset stop time difference value.

5. The method of air volume compensation for a range hood according to claim 2 or 4, wherein: In step 2.1.2) or 2.2.3), when the main control chip (511) issues an offline identification instruction, the identified is the resistance value, comprising the following steps: 1) The drive chip (512) receives the offline identification flag from the main control chip (511); 2) The driving chip (512) performs offline resistance identification, and a calculated identified resistance value R is obtained new ; 3) The driving chip (512) sends R new to the master chip (511).

6. The method of air volume compensation for a range hood according to claim 5, wherein: In step 2.3), when the master chip (511) issues the offline identification instruction, the master chip (511) receives the latest R new after that, R new上 = R new and stores it, and then detects the downtime t stop of the motor (23), if t stop >t, the power of the drive chip (512) is cut off, and the drive chip (512) is in a low-power mode; in step 2.4), the master chip (511) detects the downtime of the motor (23), if t stop >t max , R = R int ; if t stop ≤ t max , R = R new ; wherein R new上 is the updated motor resistance parameter value used at the previous time before the motor parameter value is updated, R int is the initial motor resistance parameter value, and R is the current resistance parameter value of the motor (23).

7. The method of air volume compensation for a range hood according to claim 5, wherein: The motor (23) is a motor with U, V, W three phases, and each phase includes upper and lower bridge arms, and the offline resistance identification method comprises the following steps: 1) The motor (23) is closed before starting, and six bridge arms are closed; 2) The lower bridge arm (V2) of the V phase is disconnected, and the upper bridge arm (U1) of the U phase is turned on in PWM mode; 2.1) continuously detect the V phase current, when the current meets the range (A1, A2), wait for the V phase current to stabilize; 2.2) Measure the current II and the bus voltage U1 after stabilization and determine the duty cycle Duty of the upper bridge arm (V1) of phase V at this time u1 and the dead time duty cycle Duty D1 ; 2.3) After each data acquisition in steps 2.1) and 2.2), change the duty cycle to continue to increase the V phase current, when the current meets the range (A3, A4), wait for the V phase current to stabilize; 2.4) Measure the current I2 and the bus voltage U2 after stabilization and determine the duty cycle Duty of the upper bridge arm (V1) of phase V at this time u2 and the dead time duty cycle Duty D2 ; 2.5) V-phase resistance is R1 = (U2 x (Duty D1 - Duty D2 ) / (2 x (I2 - I1)); and u1 - Duty u2 ) / (2 x (I2 - I1)); and 2.6) Close all bridge arms, and after the internal current of the motor is released, exchange the bridge arms, so that the lower bridge arm (W2) of the W phase is disconnected, and the upper bridge arm (V1) of the V phase is turned on in PWM mode, in the same way as V, test to obtain the resistance R2 of the W phase; Then continue to exchange the bridge arms, so that the lower bridge arm (U2) of the U phase is disconnected, and the upper bridge arm (W1) of the W phase is turned on in PWM mode, in the same way as V, test to obtain the resistance R3 of the U phase; 2.7) Calculate (R1+R2+R3) / 3, and the obtained value is the identified resistance value; A1, A2, A3, A4 are respectively preset current thresholds, A3>A1, A4>A2.

8. The method of air volume compensation for a range hood according to claim 3 or 6, wherein: The main control chip (511) has an output pin (IN1), and the drive chip (512) has a power signal input end (OUT1). The external power input end (IN2) is stepped down by the first switching power chip (U3) and the second switching power chip (U4) to supply power to the drive chip (512). The path between the output pin (IN1) of the main control chip (511) and the power signal input end (OUT1) of the drive chip (512) is controlled by a triode (Q1). The base of the triode (Q1) and the output pin (IN1) of the main control chip (511) are connected by an optical coupler (PC1). The emitter of the triode (Q1) is connected to the external power input end (IN2), and the collector of the triode (Q1) is connected to the first switching power chip (U3).

Images