Motor controllers for electric blower motors

Abstract

The present disclosure relates to a motor controller for an electric motor, comprising a drive circuit that regulates the power supplied to the stator of the electric motor to rotate the rotor. The motor controller comprises a communication interface for receiving coefficients. The motor controller comprises a processor coupled to the drive circuit. The processor receives an airflow rate demand, calculates a speed, and calculates a torque set point based on at least the sum of a first and a second term. The first term is defined as a first coefficient multiplied by an airflow rate demand raised to a power greater than 1, and the second term is defined as a second coefficient multiplied by a power greater than 1 of the speed. The processor controls the drive circuit based on the torque set point to supply power to the electric motor. The present disclosure also relates to a method for operating the electric motor and a constant airflow system comprising the electric motor.

Description

Technical Field

[0001] The field of the present disclosure relates generally to a motor controller for an electric blower motor, and more particularly to a motor controller capable of achieving near constant airflow generation. Background Art

[0002] At least some motors are torque calibrated at manufacture to ensure that the torque output at the drive shaft of the motor matches the commanded torque. At least some motors, particularly those driving blowers, such as forward curved blowers, are further calibrated to produce approximately constant airflow during operation in either a torque control mode or a speed control mode. This calibration or characterization quantifies the airflow output at a given speed and the torque output when driving the blower. The actual airflow output will vary depending on the blower configuration, ducting, or other airflow limiting factors into which the airflow is introduced.

[0003] Constant airflow heating, ventilation and air conditioning (HVAC) systems improve thermal comfort and energy savings. Constant airflow systems can also be used in certain refrigeration systems. In a constant airflow system, a motor controller for an electric blower motor receives an airflow rate requirement, for example, a value in cubic feet per minute (CFM), and then determines a suitable motor torque or motor speed (in RPM), for example, by a polynomial or constant airflow algorithm, to approximately produce the required airflow. In a torque-controlled embodiment, for example, the motor torque is adjusted based on the monitored motor speed to produce an approximate airflow. The estimation of the actual airflow generated for a given motor torque and motor speed is subject to various variables due to differences in blower design and application. For low airflow rate requirements, i.e., low volume airflow, the estimation of the actual airflow is particularly prone to error. It is desirable to have a motor controller that can improve the accuracy of the actual airflow estimation, especially under low airflow rate requirements. Summary of the invention

[0004] On the one hand, a motor controller for an electric motor includes a drive circuit, a communication interface, and a processor. The electric motor is configured to drive a blower to generate airflow. The drive circuit is configured to adjust the power supplied to the stator of the electric motor to rotate the rotor of the electric motor and generate airflow. The communication interface is configured to receive a plurality of coefficient values ​​including at least a first coefficient value and a second coefficient value. The processor is coupled to the drive circuit and configured to receive an airflow rate demand value and calculate the speed of the electric motor. The processor is configured to calculate a torque set point for the electric motor based on at least a sum of a first term and a second term, the first term being defined as a power greater than 1 multiplied by a first coefficient value, and the second term being defined as a power greater than 1 multiplied by a second coefficient value of the speed. The processor is configured to control the drive circuit based on the torque set point to supply power to the electric motor and operate the blower to generate airflow.

[0005] On the other hand, a method of operating an electric motor configured to drive a blower to generate airflow. The method includes receiving an airflow rate demand value from a system controller. The method includes receiving a plurality of coefficient values ​​including at least a first coefficient value and a second coefficient value. The method includes receiving the speed of the electric motor. The method includes calculating a torque set point for the electric motor based on at least the sum of a first term and a second term, the first term being defined as the airflow rate demand value multiplied by the first coefficient value to a power greater than 1, and the second term being defined as the speed multiplied by the second coefficient value to a power greater than 1. The method controls a drive circuit for the electric motor based on the torque set point to supply power to the electric motor and operate the blower to generate airflow.

[0006] On the other hand, a constant airflow system is provided. The constant airflow system includes a blower motor, a sensor and a motor controller. The motor is coupled to the blower and configured to drive the blower to generate airflow. The motor includes a stator and a rotor coupled to the blower. The sensor is coupled to the motor and configured to measure the speed of the motor. The motor controller is coupled to the sensor and the drive circuit. The motor controller includes a drive circuit configured to adjust the power supplied to the stator to rotate the rotor and the blower to generate airflow. The motor controller includes a processor configured to receive an airflow rate demand value and a plurality of coefficient values ​​including at least a first coefficient value and a second coefficient value. The processor is configured to calculate a torque set point of the motor according to the sum of at least a first term and a second term, the first term being defined as a power greater than 1 multiplied by the first coefficient value of the airflow rate demand value, and the second term being defined as a power greater than 1 multiplied by the second coefficient value of the speed. The processor is configured to control the drive circuit to supply power to the stator to operate the blower to generate airflow based on the torque set point. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a block diagram of an exemplary constant airflow system;

[0008] Figure 2 yes Figure 1 The logic block diagram of the constant airflow system shown;

[0009] Figure 3 is a schematic diagram of an exemplary constant air flow control loop for a torque controlled electric motor;

[0010] Figure 4 is a schematic diagram of an exemplary constant air flow control loop for a speed controlled electric motor;

[0011] Figure 5 is a flow chart of an exemplary method of operating a motor configured to drive a blower, the blower being Figure 1 A blower for the constant airflow system shown; and

[0012] Figure 6 is a graphical representation of an exemplary surface corresponding to a constant flow algorithm fit to the characterization data. DETAILED DESCRIPTION

[0013] Embodiments of the motor controller and method for operating an electric blower motor for a constant airflow system described herein provide an improved characterization (also referred to as "characterization" or "characteristic") of an electric blower motor based on motor torque, motor speed, and airflow. In a torque-controlled embodiment, for example, the characterization embodied in the motor controller and method described herein produces three or more torque-speed-airflow data points that define a surface that characterizes the operating profile of the constant airflow system. The surface is then approximated by a polynomial, airflow algorithm, or formula that defines the motor torque (T) as a function of the motor speed (N) and the airflow rate requirement (Q). Similarly, in a speed-controlled embodiment, for example, the characterization embodied in the motor controller and method described herein again produces multiple torque-speed-airflow data points that define a surface that characterizes the operating profile of the constant airflow system. The surface is then approximated by a polynomial, airflow algorithm, or formula that defines the motor torque (T) as a function of the motor speed (N) and the airflow rate requirement (Q). In an alternative speed-controlled embodiment, the above formula for motor torque (T) can be used to compare the calculated torque with the torque value in the speed-torque pair for the desired motor speed (N). The torque error value generated by the comparison can then be used to drive the motor speed (N) to a target value or a destination value. In another alternative embodiment, the motor power can be defined as a function of the motor speed (N), the motor torque (T), and the airflow rate requirement (Q). In either embodiment, the characterization described herein produces values ​​for each coefficient of each algebraic term of the polynomial. The polynomial is sometimes referred to as a constant airflow algorithm. However, it should generally be understood that due to multiple error sources and the variability of the environment and physical characteristics of the constant airflow system and the duct into which the airflow is introduced, the actual airflow generated by the constant airflow system using the constant airflow algorithm is only an approximation of the desired airflow.

[0014] Typically, a constant airflow algorithm with more terms produces a more accurate fit to the data collected during the characterization, and is therefore able to produce a more accurate estimate of the actual airflow. The fit of a given constant airflow algorithm can be further improved by enabling non-integer (e.g., real) values ​​for one or more coefficients or exponents. Therefore, the motor and motor controller must have sufficient processors, memory, communication interfaces, and software to program, store, call, and execute such a constant airflow algorithm. In addition, a greater number of terms and non-integer coefficients in a constant airflow algorithm are typically associated with a greater computational load when deriving the necessary coefficients. Typically, another result of using more terms to more accurately fit the data collected during the characterization is that any differences in the data, such as undersampling or abnormal data points (outlier data points), can be captured in the resulting surface, thereby providing an undesirable profile or possible extreme point for the resulting surface, which, in turn, produces inaccurate airflow during operation, particularly at the extreme values ​​of the operating profile of the motor and blower. In contrast, due to fewer terms and a coarser fit to the data, regression analysis tends to "filter" or "smooth" out the differences and outlier data points in the data, resulting in a surface with a gentler profile and more accurate airflow at the extremes of the running profile.

[0015] In the torque controlled embodiments of the motor controller and methods described herein, the motor torque may be defined by the following nine-term airflow algorithm, i.e., the constant airflow algorithm:

[0016] T(N,Q)=a0+a1Q+a2N+a3Q 2 +a4QN+a5N 2 +a6Q 3 +

[0017] 7Q 2 QN 2 Formula 1

[0018] Where a0, a1, a2, a3, a4, a5, a6, a7, and a8 are coefficient values ​​determined during characterization.

[0019] Alternatively, in torque controlled embodiments of the motor controllers and methods described herein, the motor torque may be defined by the following alternative six-term, seven-coefficient airflow algorithm, i.e., a constant airflow algorithm:

[0020] T(N,Q)=a0+a1Q+a2N+a3N a6 +a4Q 1.95 +a5QN Formula 2

[0021] At least some known motors and motor controllers lack a communication interface or software for transmitting, storing, and executing a constant airflow algorithm having more than five terms. In addition, at least some known motors and motor controllers lack software or firmware for performing certain non-integer mathematical operations, such as non-integer exponents. Therefore, such motor controllers will need to be improved with new communication interfaces or software to implement, for example, the nine-term or seven-term constant airflow algorithms shown above in Equations 1 and 2. Alternatively, in other torque-controlled embodiments of the motor controllers and methods described herein, the motor torque may be defined by the following alternative five-term airflow algorithm, i.e., the constant airflow algorithm:

[0022] T(N,Q)=a0+a1N+a2N k +a3Q j +a4QN Formula 3

[0023] Wherein, k and j are constant values ​​determined before performing, for example, regression analysis to determine coefficients a0, a1, a2, a3, a4, a5, a6, a7, and a8. For example, in some embodiments, k=1.6 and j=1.95.

[0024] Alternatively, in speed controlled embodiments of the motor controllers and methods described herein, the motor speed may be defined by the following airflow algorithm, i.e., a constant airflow algorithm:

[0025]

[0026] Where j and k are constant values ​​determined before performing, for example, a regression analysis to determine coefficients a0, a1, a2, a3, a4, and a5. For example, in some embodiments, k=0.5 and j=0.5.

[0027] Prior to the operation of the motor controller described herein, the motor controller receives the value of the coefficient (A) generated by the regression analysis of the characterization data for the motor and the blower. The coefficient (A) corresponds to a programmable variable within the selected constant airflow algorithm that is stored in a memory on the motor controller and can be executed by the processor during operation. In some embodiments, certain other constants for the constant airflow algorithm or alternative constant airflow algorithms can be defined and stored in a non-volatile memory such as an EEPROM. In some embodiments, the value of the coefficient (A) can be received from an external system controller or other device via a wired or wireless communication channel. In another alternative embodiment, the value of the coefficient (A) can be programmed into the motor controller by a technician or installer when installing the motor controller.

[0028] During operation, the motor controller typically receives an airflow rate demand (Q) from an external system controller and one of the motor torque (T) and motor speed (N) measured at the motor. The other of the motor torque (T) and motor speed (N) is calculated. For example, in a torque-controlled embodiment, the system controller sends the airflow rate demand (Q) to the motor controller, and the motor controller calculates the motor torque (T) to be ordered to the electric blower motor based on the measured motor speed (N). In an alternative embodiment, the system controller transmits a discrete selection or index of a specific airflow rate demand (Q) from a plurality of values ​​in a table stored in a memory. The motor speed (N) can be determined based on the current signal supplied to the stator winding, or can be directly measured by a sensor. Then, the torque control loop / loop is recursively executed or iterated until the motor torque (T) converges to the target torque. The torque control loop can be executed, for example, every 100 milliseconds. In an alternative embodiment, the torque control loop cycle can be extended or shortened according to, for example, a specific motor, blower, or duct configuration.

[0029] Likewise, in a speed controlled embodiment, the system controller transmits the airflow rate demand (Q) to the motor controller, and the motor controller calculates the motor speed (N) to be commanded to the electric blower motor based on the measured motor torque (T). As described above with respect to the motor speed (N), the motor torque (T) can be determined based on the current signal supplied to the stator windings, or can be measured directly by a sensor. The speed control loop then iterates until the motor speed (N) converges to the target speed.

[0030] Figure 1 is a block diagram of a constant airflow system 100. System 100 includes duct 102, blower 104, electric motor (also referred to herein as "motor") 106, motor controller 108, and system controller 110. In other embodiments, system 100 may include additional, fewer, or alternative components, including those described elsewhere herein.

[0031] Blower 104 is configured to generate airflow 112 that is directed through duct 102. In at least some embodiments, blower 104 is a forward curved centrifugal blower. In other embodiments, blower 104 is a different type of blower. Duct 102 is configured to direct airflow to circulate and distribute within a building, vehicle or other structure. Duct 102 has airflow restrictions that affect the airflow shown from blower 104. Airflow restrictions are based on various parameters that can affect the airflow within system 100, such as, but not limited to, the internal dimensions of duct 102, open or closed dampers, contaminants (e.g., dust) within duct 102, the geometry of duct 102, etc.

[0032] The motor 106 is configured to drive the blower 104 to generate an airflow 112 entering the duct 102. In at least some embodiments, the motor 106 is an induction motor configured to convert electricity into mechanical power. In an alternative embodiment, the motor 106 is a permanent magnet motor. In one example, the motor 106 is connected to a wheel (not shown) of the blower 104 and is configured to rotate the wheel. In this exemplary embodiment, the motor 106 is configured to operate with multiple torque output levels (i.e., torque controlled) to increase or decrease the corresponding motor speed. Increasing or decreasing the motor speed of the motor 106 causes the motor 106 to drive the blower 104 to generate the corresponding airflow. The airflow 112 generated by the blower 104 depends at least in part on the motor speed of the motor 106 and the airflow restriction of the duct 102. In some embodiments, the motor 106 is integrated with the blower 104.

[0033] Alternatively, the motor 106 is configured to operate at multiple speed output levels (i.e., speed controlled) to increase or decrease the corresponding motor torque. As in the torque controlled embodiment, increasing or decreasing the torque of the motor 106 causes the motor 106 to drive the blower 104 to generate the corresponding airflow.

[0034] The motor controller 108 is communicatively coupled to the motor 106 to operate the motor 106. More specifically, the motor controller 108 supplies power of a specific current and frequency to the stator windings of the motor 106 to operate the motor 106. By adjusting the current and frequency, the motor controller 108 controls the torque (or alternatively the speed in a speed-controlled embodiment) of the motor 106, thereby facilitating the control of the speed of the motor 106. In other embodiments, the motor controller 108 may be communicatively coupled to a second controller (not shown) associated with the motor 106. In such an embodiment, the motor controller 108 may be configured to transmit a control signal to the second controller to instruct the second controller to operate the motor 106. In such an embodiment, the motor controller 108 may be separate from or remote from the motor 106. For example, the motor controller 108 may be located within the HVAC assembly along with the blower 104 and the motor 106. In another embodiment, for example, the motor controller 108 may be located with the thermostat system or system controller 110.

[0035] The motor controller 108 includes a processor 114, a memory 116 communicatively coupled to the processor 114, and a sensor system 118. The processor 114 is configured to execute instructions stored in the memory 116 to cause the motor controller 108 to function as described herein. For example, the memory 116 is configured to store a constant airflow algorithm to be executed by the processor 114. The memory 116 is also configured to store a plurality of coefficient values ​​for use in the constant airflow algorithm. In addition, the memory 116 is configured to store data to facilitate calibration of the motor 106. In some embodiments, the motor controller 108 may include a plurality of processors 114 and / or memories 116. In other embodiments, the memory 116 may be integral with the processor 114. In one example, the memory 116 includes a plurality of data storage devices to store instructions and data as described herein.

[0036] The sensor system 118 includes one or more sensors configured to detect the motor 106. In some embodiments, the sensor system 118 is omitted and the motor torque and speed are determined based on the current signal supplied to the stator winding of the motor 106. In one embodiment, the sensor system 118 is configured to detect the frequency output of the motor 106 by the motor controller 108. The sensor system 118 can monitor other data associated with the motor 106, such as but not limited to motor speed, torque, power, etc. In some embodiments, the sensor system 118 is configured to monitor the airflow output of the blower 104. For example, the sensor system 118 may include an air pressure sensor configured to monitor the air pressure within the duct 102. In some embodiments, the sensor system 118 monitors the motor 106 by the motor controller 108. In such embodiments, the sensor system 118 can be integrated with the processor 114. In other embodiments, at least some sensors of the sensor system 118 can be mounted on the motor 106 and transmit sensor data back to the motor controller 108.

[0037] In one embodiment, motor controller 108 is configured to calibrate electric motor 106 for multiple airflow output levels to determine corresponding torque and speed pairs. The resulting airflow-torque-speed data points define a surface that further defines an operating profile of constant airflow system 100.

[0038] The motor controller 108 includes a drive circuit 120. The drive circuit 120 supplies power to the stator windings of the motor 106 based on control signals received from the processor 114. The drive circuit 120 may include, for example, various power electronics for conditioning the line frequency alternating current (AC) power to be supplied to the stator windings of the motor 106 with a desired current (i.e., phase and amplitude) and frequency. Such power electronics may include, for example, but not limited to, one or more rectifier stages, power factor correction (PFC) circuits, filters, transient protection circuits, EMF protection circuits, inverters, or power semiconductors.

[0039] The motor controller 108 includes a communication interface 122. The communication interface 122 may include one or more wired or wireless hardware interfaces, such as a universal serial bus (USB), RS232 or other serial bus, CAN bus, Ethernet, near field communication (NFC), WiFi, Bluetooth, or any other suitable digital or analog interface, for establishing one or more communication channels between the system controller 110 and the motor controller 108. For example, in some embodiments, one or more parameters, such as a maximum airflow rate (expressed in cubic feet per minute), an airflow rate requirement, or one or more coefficient values, may be transmitted to the motor controller 108 via the communication interface 122 using a pulse width modulated signal. The communication interface 122 also includes a software or firmware interface for receiving one or more motor control parameters and writing them to, for example, the memory 116. In some embodiments, the communication interface 122 includes, for example, a software application programming interface (API) for providing one or more coefficient values ​​for the constant airflow algorithm. In such an embodiment, the received coefficient values ​​are provided to the processor 114, processed, and stored in the memory 116 together with the constant airflow algorithm for subsequent execution by the processor 114 during operation of the motor 106.

[0040] In some embodiments, the memory 116 is configured to store two or more constant airflow algorithms. Alternatively, the memory 116 may be configured to store a single constant airflow algorithm and one or more sets of constants to be used by the algorithm. For example, in one embodiment, the memory 116 is configured to store Figure 2The seven-term constant airflow algorithm shown. When the motor 106 and the motor controller 108 are configured to receive seven or more coefficients, the processor 114 is configured to receive the coefficients via the communication interface 122 and provide these coefficients for use by the constant airflow algorithm. Alternatively, where the communication interface 122 includes a hardware or software interface limited to communication for five terms of the constant airflow algorithm, the processor 114 is configured to retrieve a set of constants to be used for five of the seven coefficients that can be transmitted through the communication interface 122. For example, a2 or a3 can be programmed or hard-coded in the memory 116 as a constant value, such as 1, or a6 can be programmed in the memory 116 as a constant value, such as 1. In such a limited motor controller 108, a constant airflow algorithm with more than five terms can be used.

[0041] Figure 2 is a logic block diagram of a constant airflow system 100, which includes a motor 106 and a motor controller 108 (in Figure 1 1 ). The processor 114 transmits control signals to the drive circuit 120 to control the current and frequency of the power supplied to the motor 106. The processor 114 executes, for example, a constant airflow algorithm 200, such as the algorithm described above in Equation 1, Equation 2, or Equation 3, to calculate one of a torque set point and a speed set point for controlling the drive circuit 120 and the motor 106. Execution of the algorithm is typically performed periodically, for example at 10 Hz, to update the torque set point or the speed set point. During operation, the processor 114 receives an airflow rate demand value Q, 202 used in the constant airflow algorithm 200. In some embodiments, the processor 114 may receive an airflow rate demand value Q, 202 directly from a system controller such as the system controller 110 (in Figure 1 1, 202. Alternatively, the system controller 110 may supply the airflow rate demand value Q, 202 using a discrete input representing an index into a table of airflow rate demand values ​​stored in a memory from which the processor 114 receives the airflow rate demand value Q, 202. Alternatively, the system controller 110 may supply a pulse width modulated (PWM) signal that varies proportionally between two airflow rate demand values. In yet another alternative embodiment, the system controller 110 may supply a digital command including the airflow rate demand value Q, 202.

[0042] Processor 114 also receives coefficient values ​​A, 204 used in constant airflow algorithm 200. Coefficient values ​​A, 204 may be obtained, for example, from system controller 110, a memory such as memory 116 (in Figure 1) or another external device. In some embodiments, the processor 114 receives the coefficient values ​​A, 204 when the constant airflow system 100 is manufactured, installed, or powered on, for example, and the processor 114 operates with those same values ​​from that point on unless it is reset, reprogrammed, or recalibrated by a technician or other user. In other embodiments, the processor 114 may receive periodic updates of the coefficient values ​​A, 204 from a remote device, and the constant airflow algorithm 200 adopts the latest values ​​for a given iteration.

[0043] In some embodiments, the constant airflow algorithm 200 is selected from a plurality of algorithms stored in the memory 116. The memory 116 may include, for example, a read-only memory, such as an EEPROM. The constant airflow algorithm 200 is retrieved / obtained from the memory 116 based on a user selection or a selection by the system controller 110. Then, for example, the system controller 110 then transmits the corresponding coefficient value A, 204, the corresponding memory address for the space in the memory 116 containing the appropriate coefficient value, or an identifier or "pointer" to such a memory address to the processor 114. The processor 114 then obtains access to the corresponding space in the memory 116 and reads the coefficient value A, 204.

[0044] The processor 114 receives at least one of a measured speed N, 206 and a measured torque 208 of the motor 106. It is used in the constant airflow algorithm 200. For example, the measured speed N, 206 can be derived from a current signal supplied to the stator winding of the motor 106. For example, such a current signal can be measured by a current sensor, and the measured speed N, 206 is derived from the measurement result. Alternatively, the processor 114 can receive a frequency measurement from a frequency sensor on the motor 106, the output of which can be converted to the measured speed N, 206. Alternatively, the motor speed can be measured by any other suitable method, such as by further analyzing the current signal supplied to the stator winding of the motor 106. For example, the measured torque T, 208 can be derived from the current signal supplied to the stator winding of the motor 106. For example, such a current signal can be measured by a current sensor and the torque T, 208 can be derived from the measurement result, such as by inferring that the torque output is equal to the command torque obtained by means of a closed-loop control system. Alternatively, the processor 114 can receive a torque measurement from a torque sensor on the motor 106 or alternatively by any other suitable method.

[0045] During operation, the processor 114 uses the several inputs described above, including the airflow rate demand value Q, 202 and at least one of the measured speed N, 206 and the measured torque T, 208, to execute the constant airflow algorithm 200. While executing the constant airflow algorithm 200, the processor 114 calculates one of a torque set point and a speed set point for controlling the drive circuit 120. The drive circuit 120 then supplies the required current and frequency of AC power to the motor 106 to rotate the blower 104 (at Figure 1 ).

[0046] Figure 3 is used to control a torque controlled motor such as a constant air flow system 100 (in Figure 1 and Figure 2 1 . The control loop 300 may be implemented, for example, in the motor controller 108 or the processor 114, and illustrates controlling the motor 106 by executing the constant airflow algorithm 200 to calculate a torque set point 302. The constant airflow algorithm 200 receives an airflow rate demand Q, 202 and a measured speed N, 206, and calculates the torque set point 302 based on a polynomial such as shown in Equation 1, Equation 2, or Equation 3.

[0047] Figure 4 is a schematic diagram of one embodiment of a constant airflow control loop 400 for controlling a speed-controlled motor, such as the constant airflow system 100 (in Figure 1 and Figure 2 4. The control loop 400 may be implemented, for example, in the motor controller 108 or the processor 114, and illustrates controlling the motor 106 by executing the constant airflow algorithm 200 to calculate a speed set point 402. The constant airflow algorithm 200 receives an airflow rate demand Q, 202 and a measured torque T, 208, and calculates the speed set point 402 based on a polynomial similar to that shown in Equation 1, Equation 2, or Equation 3.

[0048] Figure 5 is a flow chart of one embodiment of a method 500 of operating an electric motor configured to drive a blower, such as a constant airflow system 100 (in Figure 1 106 and the blower 104. Figure 1 and Figure 5 , the method 500 may be implemented in a motor controller such as the motor controller 108 (in Figure 1 and Figure 2106). The motor controller 108 receives 510 an airflow rate demand value from the system controller 110. The airflow rate demand value can be transmitted as a value in a digital format, for example, or alternatively as a continuous pulse width modulated signal representing the required airflow rate demand. The motor controller 108 also receives 520 multiple coefficient values ​​from, for example, the system controller 110. The multiple coefficient values ​​include at least a first coefficient value and a second coefficient value. At least one of the motor speed and the motor torque is calculated 530 based on one or more measured motor parameters such as the current supplied to the stator winding of the motor 106. More specifically, the motor controller 108 can analyze the current signal supplied to the stator winding to calculate the motor speed, the motor torque, or both. In an alternative embodiment, at least one of the motor speed and the motor torque is measured by, for example, the sensor system 118 and received by the motor controller 108. The motor controller 108, and more specifically the processor 114, calculates 540 the torque set point 302 or the speed set point 402 (in 1, 2, or 3, respectively) for the motor 106 by executing an airflow algorithm (e.g., the constant airflow algorithm of Equation 1, Equation 2, or Equation 3). Figure 3 and Figure 4 More generally, the processor 114 calculates 540 the torque setpoint 302 or the speed setpoint 402 based on the sum of at least a first term and a second term. The first term is defined as a first coefficient value multiplied by a desired airflow rate value to a power greater than 1 (e.g., a3Q X,X＞1 The second term is defined as the second coefficient value multiplied by at least one of the measured torque and the measured speed to a power greater than 1 (e.g., a4N Y,Y＞1 or a4T Y,Y＞1 ).

[0049] The torque set point or speed set point is then provided to the drive circuit 120 to control 550 the drive circuit 120. The drive circuit 120 then supplies a current and frequency of power corresponding to the set point to the motor 106 to operate the blower 104 to generate the airflow 112.

[0050] Figure 6600 is an illustration of an exemplary surface 600 associated with the nine-term constant airflow algorithm described above in Equation 1, wherein the characteristic data 602 is generally concentrated at high speeds and high volume airflows. The illustration is shown on three axes (the three axes converge at the origin 604): torque (T), speed (N), and airflow rate demand (Q). Surface 600 includes regions 606 and 608, where, for the nine-term constant airflow algorithm, the calculated torque (T) is zero or negative. Therefore, the characteristic description data 602 must be supplemented to avoid these areas on the surface 600, or the operating profile (or "operating profile" or "operating curve") must be reduced to exclude certain extreme values ​​of torque (T), speed (N), and airflow rate demand (Q). Alternatively, a constant airflow algorithm with fewer terms can produce a coarser fit to the data and avoid producing a surface with regions similar to regions 606 and 608.

[0051] The methods and systems described herein may be implemented using computer programming or engineering techniques, including computer software, firmware, hardware, or any combination or subset thereof, wherein the technical effects may include at least one of the following: (a) improving motor performance at low airflow output levels; (b) improving the accuracy of inferences of actual airflow; (c) improving surface fit to characterization data for a given motor and blower; (d) maintaining backward compatibility with existing hardware and software interfaces for motors and motor controllers; (e) improving thermal comfort and energy savings for operating constant airflow systems; and (f) improving the ability of motors and blowers to match the performance of previously installed motors and blowers to further support backward compatibility.

[0052] In the preceding description and the following claims, a number of terms are cited which have the following meanings.

[0053] As used herein, an element or step recited in the singular and preceded by the word "a" or "an" should be understood not to exclude a plurality of elements or steps, unless such exclusion is clearly stated. In addition, references to "exemplary embodiments" or "one embodiment" in the present disclosure should not be interpreted as excluding the existence of additional embodiments that also incorporate the described features.

[0054] "Optional" or "optionally" means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event occurs and instances where it does not.

[0055] Approximations as used herein in the specification and claims may be applicable to any quantitative representation of a modification that permits change without causing a change in the basic function to which it relates. Therefore, the value modified by one or more terms such as "about", "approximately" and "roughly" is not limited to the specified exact value. In at least some examples, approximations may correspond to the precision of the instrument used to measure the value. Here, and in the specification and claims, range limitations may be combined or interchanged. Unless the context or language indicates otherwise, these ranges are identified and include all subranges contained therein.

[0056] Some embodiments include the use of one or more electronic processing or computing devices. As used herein, the terms "processor" and "computer" and related terms (e.g., "processing device," "computing device," and "controller") are not limited to those integrated circuits referred to as computers in the art, but broadly refer to processors, processing devices, controllers, general-purpose central processing units (CPUs), graphics processing units (GPUs), microcontrollers, microcomputers, programmable logic controllers (PLCs), reduced instruction set computers (RISC) processors, field programmable gate arrays (FPGAs), digital signal processing (DSP) devices, application-specific integrated circuits (ASICs), and other programmable circuits or processing devices capable of performing the functions described herein, and these terms are used interchangeably herein. The above embodiments are merely examples, and therefore are not intended to limit the definitions or meanings of the terms processor, processing device, and related terms in any way.

[0057] In the embodiments described herein, the memory may include, but is not limited to, non-transitory computer-readable media, such as flash memory, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and non-volatile RAM (NVRAM). As used herein, the term "non-transitory computer-readable medium" is intended to represent any tangible computer-readable medium, including but not limited to non-transitory computer storage devices, including but not limited to volatile and non-volatile media, removable and non-removable media, such as firmware, physical and virtual storage, CD-ROM, DVD, and any other digital source, such as a network or the Internet, and digital means that have not yet been developed, with the only exception of ephemeral propagation signals. Alternatively, a floppy disk, compact disk read-only memory (CD-ROM), magneto-optical disk (MOD), digital versatile disk (DVD), or any other computer-based device implemented in any method or technology for short-term and long-term storage of information such as computer-readable instructions, data structures, program modules and submodules, or other data may also be used. Therefore, the methods described herein may be encoded as executable instructions, such as "software" and "firmware" embodied in non-transitory computer-readable media. In addition, as used herein, the terms "software" and "firmware" are interchangeable and include any computer program stored in a memory for execution by a personal computer, workstation, client, and server. Such instructions, when executed by a processor, cause the processor to perform at least a portion of the methods described herein.

[0058] Moreover, in the embodiments described herein, the additional input channels may be, but are not limited to, computer peripherals associated with an operator interface such as a mouse and keyboard. Alternatively, other computer peripherals may be used, which may include, for example, but are not limited to, a scanner. Furthermore, in this exemplary embodiment, the additional output channels may include, but are not limited to, an operator interface monitor.

[0059] The systems and methods described herein are not limited to the specific embodiments described herein, but rather, components of the systems and / or steps of the methods may be utilized independently and separately from other components and / or steps described herein.

[0060] Although the specific features of various embodiments of the present invention may be shown in some drawings and not in other drawings, this is only for convenience. According to the principles of the present invention, any feature of the drawings may be combined with any feature of any other drawings to discuss and / or claim rights.

[0061] This written description uses examples, including the best mode, to provide details about the disclosure, and also enables any person skilled in the art to implement the disclosure, including making and using any device or system and performing any combined method. The scope of the disclosure that can be patented is defined by the claims, and may include other examples that occur to those skilled in the art. If such other examples do not have structural elements that are different from the literal language of the claims, or they include equivalent structural elements that are not substantially different from the literal language of the claims, such other examples are considered to be included in the scope of protection of the claims.

Claims

1. A motor controller configured to drive an electric motor of a blower to generate airflow, the motor controller comprising: a drive circuit configured to regulate power supplied to a stator of the motor to cause a rotor of the motor to rotate and generate airflow; and a communication interface configured to receive a plurality of coefficient values ​​including at least a first coefficient value and a second coefficient value; a processor coupled to the driver circuit and configured to: Receive air flow rate demand value Q; Calculating the speed N of the motor; calculating a torque set point T of the motor based on at least a sum of a first term defined as a first coefficient value multiplied by a power greater than 1 of an airflow rate demand value Q and a second term defined as a second coefficient value multiplied by a power greater than 1 of a speed N; and The drive circuit is controlled based on the torque set point T to supply power to the motor and operate the blower to generate airflow. 2 . The motor controller of claim 1 , further comprising a memory configured to store the plurality of coefficient values, and wherein the processor is further configured to retrieve the plurality of coefficient values ​​from the memory.

3. The motor controller according to claim 1, wherein: The communication interface is also configured to receive the plurality of coefficient values ​​from a system controller.

4. The motor controller according to claim 1, wherein: The torque set point T is calculated from the speed N and the airflow rate demand value Q according to the airflow algorithm defined as follows: <h2 style=";text-align:left;direction:ltr">T(N, Q) = a0 + a1N + a2N<h2 style=";text-align:left;direction:ltr"> k <h2 style=";text-align:left;direction:ltr"> +a3Q<h2 style=";text-align:left;direction:ltr"> j <h2 style=";text-align:left;direction:ltr"> +a4QN, Wherein j and k are predetermined constant values, and the plurality of coefficient values ​​include a0, a1, a2, a3 and a4.

5. The motor controller according to claim 4, wherein: The torque set point T is calculated from the speed N and the airflow rate demand value Q according to the airflow algorithm defined as follows: <h2 style=";text-align:left;direction:ltr">T(N, Q) = a0 + a1N + a2N<h2 style=";text-align:left;direction:ltr"> k <h2 style=";text-align:left;direction:ltr"> +a3Q<h2 style=";text-align:left;direction:ltr"> 1.95 <h2 style=";text-align:left;direction:ltr"> +a4QN, Wherein k is a predetermined constant value, and the plurality of coefficient values ​​include a0, a1, a2, a3, and a4.

6. The motor controller according to claim 4, wherein: The torque set point T is calculated from the speed N and the airflow rate demand value Q according to the airflow algorithm defined as follows: T(N,Q)=a0+a1Q+a2N+a3N a6 +a4Q j +a5QN, Wherein j is a predetermined constant value, and the plurality of coefficient values ​​include a0, a1, a2, a3, a4, a5 and a6.

7. A method of operating a motor configured to drive a blower to generate airflow, the method comprising: receiving an airflow rate demand value Q from a system controller; receiving a plurality of coefficient values ​​including at least a first coefficient value and a second coefficient value; Calculating the speed N of the motor; calculating a torque set point T for the electric motor based on at least a sum of a first term defined as a first coefficient value multiplied by a power greater than 1 for the airflow rate demand value Q and a second term defined as a second coefficient value multiplied by a power greater than 1 for the speed N; and The drive circuit of the motor is controlled based on the torque set point T to supply power to the motor and operate the blower to generate airflow.

8. The method according to claim 7, further comprising: receiving a spatial address in a memory; as well as An airflow algorithm selected from a plurality of airflow algorithms is retrieved from the space in the memory.

9. The method according to claim 7, wherein: Calculating the torque set point T includes calculating the torque set point T based on the speed N and the airflow rate demand value Q according to an airflow algorithm defined as follows: <h2 style=";text-align:left;direction:ltr">T(N, Q) = a0 + a1N + a2N<h2 style=";text-align:left;direction:ltr"> k <h2 style=";text-align:left;direction:ltr"> +a3Q<h2 style=";text-align:left;direction:ltr"> j <h2 style=";text-align:left;direction:ltr"> +a4QN, Wherein j and k are predetermined constant values, and the plurality of coefficient values ​​include a0, a1, a2, a3 and a4.

10. The method according to claim 7, wherein: Calculating the torque set point T includes calculating the torque set point T based on the speed N and the airflow rate demand value Q according to an airflow algorithm defined as follows: T(N,Q)=a0+a1Q+a2N+a3N a6 +a4Q j +a5QN, Wherein j is a predetermined constant value, and the plurality of coefficient values ​​include a0, a1, a2, a3, a4, a5 and a6.

11. The method according to claim 10, further comprising: receiving a spatial address in a memory; as well as At least two constant values ​​are retrieved from the space in the memory to replace at least two of a0, a1, a2, a3, a4, a5 and a6 in the airflow algorithm, respectively.

12. The method according to claim 7, wherein: Receiving the plurality of coefficient values ​​includes receiving at least one non-integer exponent value.

13. The method according to claim 7, wherein: Receiving the speed N comprises: detecting a frequency at which the motor is energized; and The frequency is converted into the speed N of the motor.

14. A constant airflow system comprising: Blower; an electric motor coupled to the blower and configured to drive the blower to generate airflow, the electric motor comprising a stator and a rotor coupled to the blower; a current sensor coupled to the motor and configured to measure a stator current, from which a speed N of the motor is derived; and a motor controller coupled to the current sensor, the motor controller comprising a drive circuit configured to regulate power supplied to the stator to rotate the rotor and the blower to generate airflow, and a processor configured to: receiving an airflow rate demand value Q and a plurality of coefficient values ​​including at least a first coefficient value and a second coefficient value, calculating the torque set point T of the motor based on at least the sum of a first term and a second term, wherein the first term is defined as the airflow rate demand value Q raised to a power greater than 1 multiplied by a first coefficient value, and the second term is defined as the speed N raised to a power greater than 1 multiplied by a second coefficient value, The drive circuit is controlled based on the torque set point T to supply power to the stator, thereby operating the blower to generate airflow.

15. The constant airflow system of claim 14, wherein: The blower includes a forward curved blower.

16. The constant airflow system of claim 14, further comprising a system controller configured to transmit the airflow rate demand value Q to the motor controller.

17. The constant airflow system of claim 16, wherein: The motor controller further includes a communication interface configured to establish a communication channel with the system controller and receive the plurality of coefficient values ​​through the communication channel.

18. The constant airflow system of claim 14, wherein: The motor controller also includes a memory in which a plurality of airflow rate demand values ​​Q are stored, and wherein the processor is further configured to retrieve the airflow rate demand value Q from the memory based on a memory address corresponding to a selection of at least one of a user and a system controller.

19. The constant airflow system of claim 14, wherein: The processor is further configured to calculate the torque set point T from the speed N and the airflow rate demand value Q according to an airflow algorithm defined as follows: <h2 style=";text-align:left;direction:ltr">T(N, Q) = a0 + a1N + a2N<h2 style=";text-align:left;direction:ltr"> k <h2 style=";text-align:left;direction:ltr"> +a3Q<h2 style=";text-align:left;direction:ltr"> j <h2 style=";text-align:left;direction:ltr"> +a4QN, Wherein j and k are predetermined constant values, and the plurality of coefficient values ​​include a0, a1, a2, a3 and a4.

20. The constant airflow system of claim 14, wherein: The processor is further configured to calculate the torque set point T from the speed N and the airflow rate demand value Q according to an airflow algorithm defined as follows: T(N,Q)=a0+a1Q+a2N+a3N a6 +a4Q j +a5QN, Wherein j is a predetermined constant value, and the plurality of coefficient values ​​include a0, a1, a2, a3, a4, a5 and a6.

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