CN117254720A - Power control device and power control method - Google Patents
Power control device and power control method Download PDFInfo
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- CN117254720A CN117254720A CN202210655315.4A CN202210655315A CN117254720A CN 117254720 A CN117254720 A CN 117254720A CN 202210655315 A CN202210655315 A CN 202210655315A CN 117254720 A CN117254720 A CN 117254720A
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- 238000000034 method Methods 0.000 title claims abstract description 38
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- 230000009466 transformation Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 13
- 238000004378 air conditioning Methods 0.000 description 7
- 239000000314 lubricant Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/02—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the kind of motor
- H02P25/022—Synchronous motors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
- H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
- H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
- H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/02—Providing protection against overload without automatic interruption of supply
- H02P29/032—Preventing damage to the motor, e.g. setting individual current limits for different drive conditions
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/60—Controlling or determining the temperature of the motor or of the drive
- H02P29/64—Controlling or determining the temperature of the winding
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/28—Arrangements for controlling current
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
The present disclosure relates to a power control apparatus and a power control method. The power control device is used for controlling an inverter controlled by a pulse width modulation signal to provide heating power for heating the compressor to windings of a stator of a motor of the compressor. According to one embodiment of the present disclosure, the power control apparatus includes: a power determination unit that determines a power of the heating power as an actual heating power based on the power information related to the inverter; and a power closed-loop controller generating a power control signal for closed-loop controlling the actual heating power with the preset heating power as a reference based on the preset heating power and the actual heating power. The power control device and the power control method of the present disclosure have at least one of the following advantages: the control precision of the heating power of the stator heating is improved; the motor is prevented from being damaged; the dependence on motor parameters is low; the applicability is wide.
Description
Technical Field
The present disclosure relates generally to motor control, and more particularly, to an electric power control apparatus and an electric power control method for heating electric power during stator heating.
Background
Heating Ventilation and Air Conditioning (HVAC) systems such as air conditioners have compressors installed outdoors. The compressor has a motor for compressing a refrigerant by rotation, and an oil sump or the like for accommodating lubricating oil, wherein the motor has a stator having a plurality of turns serving as windings, and a rotor.
In the compressor off state, several problems may occur, including: refrigerant migration, refrigerant and lubricant mixing, compressor crankcase condensation. These problems are particularly serious in the case where the outdoor environment temperature is too low. The outdoor environment temperature is too low, the viscosity of the lubricant of the compressor increases, and too much liquid refrigerant may be mixed into the lubricant. Therefore, in case that the outdoor environment temperature is too low, after the air conditioner is powered up, the compressor is directly started to rotate the motor thereof, and the compressor may be failed to be started, damaged or damaged to various degrees. If the compressor is properly heated, the temperature of the lubricant can be increased, the viscosity of the lubricant can be reduced, and the possibility of mixing liquid refrigerant into the lubricant can be reduced, thereby improving the lubrication condition of the rotating members of the compressor.
Common ways to solve the above problems are: under the condition that the outdoor environment temperature is too low, the crankcase of the compressor is heated to be above a preset temperature under the condition that the compressor is in a shutdown state (not rotated), and then the compressor is started to rotate. This typically requires a crankcase heater. The heater is a heating device specifically designed to heat the compressor. As an alternative to heating compressors, stator heating with less equipment modification and lower cost has been proposed. In particular, stator heating refers to heating the compressor by injecting current into a heating resistor by using windings of the stator of the motor of the compressor as the heating resistor.
Disclosure of Invention
A brief summary of the disclosure is presented below to provide a basic understanding of some aspects of the disclosure. It should be understood that this summary is not an exhaustive overview of the disclosure. It is not intended to identify key or critical elements of the disclosure or to delineate the scope of the disclosure. Its purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.
According to one aspect of the present disclosure, an electrical control device is provided for controlling an inverter controlled by a pulse width modulated signal to provide heating electrical energy to heat a compressor to windings of a stator of a motor of the compressor. The power control device includes: a power determination unit that determines a power of the heating power as an actual heating power based on the power information related to the inverter; and a power closed-loop controller generating a power control signal for closed-loop controlling the actual heating power with the preset heating power as a reference based on the preset heating power and the actual heating power.
According to another aspect of the present disclosure, an electrical power control method is provided for controlling an inverter controlled by a pulse width modulated signal to provide heating electrical power to heat a compressor to windings of a stator of a motor of the compressor. The power control method includes: determining a power of the heating power as an actual heating power based on the power information related to the inverter; and generating a power control signal for closed-loop controlling the actual heating power with the preset heating power as a reference based on the preset heating power and the actual heating power.
The power control device and the power control method of the present disclosure have at least one of the following advantages: the control precision of the heating power of the stator heating is improved; the motor is prevented from being damaged; the dependence on motor parameters is low; the applicability is wide.
Drawings
The above and other objects, features and advantages of the present disclosure will be more readily appreciated by referring to the following description of the embodiments of the present disclosure with reference to the accompanying drawings. The drawings are only for the purpose of illustrating the principles of the present disclosure. The dimensions and relative positioning of the elements in the figures are not necessarily drawn to scale. Like reference numerals may denote like features. In the drawings:
FIG. 1 illustrates a block diagram of a power control device according to one embodiment of the present disclosure;
fig. 2 illustrates a circuit diagram of an example inverter, according to one embodiment of the present disclosure;
FIG. 3 illustrates a block diagram of a motor control structure according to one embodiment of the present disclosure;
FIG. 4 illustrates a block diagram of a motor control structure according to one embodiment of the present disclosure;
FIG. 5 illustrates test results of controlling heating power using a power control device according to one embodiment of the present disclosure;
FIG. 6 illustrates an exemplary formula for calculating power consumption of an inverter;
FIG. 7 illustrates an electrical angle setting of a motor according to one embodiment of the present disclosure;
FIG. 8 illustrates a block diagram of an example air conditioning system, according to one embodiment of this disclosure;
FIG. 9 illustrates an exemplary flow chart of a power control method according to one embodiment of the present disclosure; and
fig. 10 shows a block diagram of a power control device according to one embodiment of the present disclosure.
Detailed Description
Exemplary embodiments of the present disclosure will be described hereinafter with reference to the accompanying drawings. In the interest of clarity and conciseness, not all features of an actual embodiment are described in the specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions may be made to achieve the developers' specific goals, and that these decisions may vary from one implementation to another.
It should be noted here that, in order to avoid obscuring the present disclosure due to unnecessary details, only the device structures closely related to the scheme according to the present disclosure are shown in the drawings, and other details not greatly related to the present disclosure are omitted.
It is to be understood that the present disclosure is not limited to the described embodiments due to the following description with reference to the drawings. In this context, embodiments may be combined with each other, features replaced or borrowed between different embodiments, one or more features omitted in one embodiment, where possible.
The method of the present disclosure may be implemented by a circuit having a corresponding functional configuration. The circuitry includes circuitry for the processor.
Conventional stator heating techniques employ an open loop approach to control heating power, wherein a look-up table is utilized to determine the output current to achieve a desired power level. The lookup table is configured based on a nominal value (nominal value) of the motor. This causes the following problems: open loop control does not allow for proper adjustment of the variation (i.e., the motor winding resistance changes due to heating). The inventors have noted that in conventional stator heating techniques, the windings are energized to heat at a fixed current, and the temperature increases and the resistance of the windings increases. Also under heating current, the actual heating power becomes large due to the increase in resistance of the winding. This results in large fluctuation of the heating power, and the difference between the actual heating power and the preset heating power is beyond expectations. The fixed current is provided to the stator winding, and the error between the actual heating power and the preset heating power is large, for example, the error reaches 20W. Thus, heating for a long time or in the case of extreme temperature changes, resulting in higher than desired power being supplied to the stator, may occur burning out the motor. In addition, variations in the motor itself may also result in different power levels. Based on this, the inventors conceived the present disclosure relating to an electric power control apparatus and an electric power control method, in which heating power is controlled by a power closed-loop control manner, and in particular, an inverter controlled by a pulse width modulation signal is closed-loop-controlled to supply heating power for heating a compressor to windings of a stator of a motor of the compressor. The heating power may be actively calculated and the calculated heating power may be fed back to the stator heating algorithm for closed loop control, whereby the heating power provided to the stator may be made stable and much more accurate. The heating power may be calculated using various methods. During stator heating, where closed loop control is performed, different electrical angles may be configured such that the stator heating profile varies. This advantageously reduces the maximum current flowing through a single stator winding. This is also beneficial to the power plant itself in terms of reliability, since the heat can be distributed more evenly throughout the plant.
One aspect of the present disclosure provides a power control apparatus. The power control apparatus of the present disclosure is exemplarily described below with reference to fig. 1.
Fig. 1 shows a block diagram of a power control device 10 according to one embodiment of the present disclosure. As shown in fig. 1, the power control apparatus 10 includes a power determination unit 101 and a power closed-loop controller 103. The power control device 10 may control an inverter controlled by the pulse width modulation signal PWM to supply heating power Eh for heating the compressor to windings of a stator of a motor of the compressor. The compressor is, for example, an electric load of an outdoor unit for an air conditioner. The power determining unit 101 is based on the power information Inf about the inverter I The power of the heating electric energy Eh is determined as the actual heating power Pa. The power closed-loop controller 103 is configured to generate a power control signal Sp for closed-loop controlling the actual heating power Pa with the preset heating power Ps as a reference, based on the preset heating power Ps and the actual heating power Pa from the power determining unit. In one example, closed loop control here may mean: controlling Pa according to an error signal based on a difference between Pa and Ps; when the error signal indicates Pa is greater than Ps, a power control signal Sp will be generated that causes Pa to decrease appropriately; when Pa is determined to be less than Ps, a power control signal Sp will be generated that causes Pa to increase appropriately; that is, the output of the inverter is sampled, and the output is controlled based on the feedback of the output. The preset heating power Ps can be determined byThe main controller of the air conditioner is given, selected by the user within a predetermined range, or given by the power determining unit 101 according to a built-in algorithm. For example, a first preset heating power Ps1 is selected at an initial stage of the heating compressor, and a second preset heating power Ps2 is selected at an end stage of the heating compressor, wherein Ps1>Ps2. The power control apparatus 10 may be implemented by a processor executing corresponding codes. Inverter-related power information Inf I Comprising the following steps: input current, input voltage, output current, output voltage of the inverter, power consumption characteristics of the inverter, component parameters of the inverter, and the like. Power information Inf I The voltage information in the power information can be directly obtained through a current sampling circuit and a voltage sampling circuit, or can be indirectly obtained based on the generated internal control parameters for the inverter, and further, an analog-to-digital conversion circuit can be used for converting the sampling signal so as to obtain a digital signal which is easy to process. The preset heating power Ps may be stored in a memory unit accessible to both the main controller and the power control device 10, so that the main controller may modify, adjust the preset heating power Ps as needed, and the power control device 10 may read the modified preset heating power Ps to control the actual heating power Pa in a closed loop. The power control device acquires power information of the inverter and generates a power control signal based on the power information to realize closed-loop control of the heating power. This is advantageous for reducing heating power errors and for achieving a better control of the heating power.
A circuit diagram of an example inverter used in the present disclosure is shown in fig. 2. In fig. 2, the inverter Inv receives the drive control signal, i.e., the pulse width modulation signal PWM, and outputs three-phase currents Ia, ib, ic to three windings of the motor M (e.g., the permanent magnet synchronous motor PMSM). The inverter Inv comprises three arms, each arm comprising 2 switching transistors and 2 freewheeling diodes, wherein the first arm comprises switching transistors S11, S12, freewheeling diodes D11, D12; the second arm comprises switching transistors S21, S22, freewheel diodes D21, D22; the third arm includes switching transistors S31, S32, freewheel diodes D31, D32.
In one embodiment, the control structure of the motor of the present disclosureThe block diagram of (a) may be as shown in fig. 3. Fig. 3 shows a block diagram of a motor control structure 30 according to one embodiment of the present disclosure. The motor control structure 30 of the motor M includes: a power determination unit 101, a power closed-loop controller 103, a rotation controller 205, a pulse width modulation unit 207, and an inverter 209. The motor M may be a three-phase Permanent Magnet Synchronous Motor (PMSM) having an a-phase winding, a b-phase winding, and a c-phase winding, which receives an a-phase current Ia (corresponding to an a-phase voltage Va) flowing to the a-phase winding, a b-phase current Ib (corresponding to a b-phase voltage Vb) flowing to the b-phase winding, and a c-phase current Ic (corresponding to a c-phase voltage Vc) flowing to the c-phase winding from the inverter 209. The inverter 209 receives the direct current power DC and the pulse width modulation signal PWM. The direct current power DC voltage V DC (i.e., output voltage of DC power supply of inverter), current I DC To characterize. The direct current power DC may be obtained by rectifying and filtering the alternating current power AC. The inverter 209 includes, for example, three arms that supply power to the motor M, each arm including a plurality of switching elements (e.g., switching transistors). The pulse width modulation signal PWM may control the power, current, voltage and timing of the power supplied to the motor M. The pulse width modulation unit 207 supplies a pulse width modulation signal PWM to the inverter 209. The pulse width modulation signal PWM having a predetermined timing may control the on and off of the switching element. In the heating mode, the power closed loop controller 103 provides a power control signal Sp to the pulse width modulation unit 207 to control the heating power. In the rotation mode, the rotation controller 205 supplies a rotation control signal Sr to the pulse width modulation unit 207 to control the rotation of the motor. The main controller of the air conditioner controls the compressor to be in a heating mode or a rotating mode by using instructions or mode parameters. For example, after the air conditioner is turned on, the main controller may determine whether an ambient temperature Te (i.e., an outdoor ambient temperature at which the compressor is located) is greater than a temperature threshold Tth; when Te is>When Tth, the compressor is instructed to enter a rotation mode (which can correspond to a standard refrigeration mode or a standard heating mode of an air conditioner); and when Te is less than or equal to Tth, indicating the compressor to enter a heating mode. In the heating mode, the pulse width modulated signal PWM causes the current injected into the stator windings to generate joule heat to heat the compressor but the rotor of the motor does not rotate (i.e., remains stationary). As an example, a heating enable flag F may be used as an example mode parameterm designates a mode of the compressor; when Te is>At Tth, the main controller sets Fm to "false"; otherwise, the main controller sets Fm to "true"; the power controller is configured to generate a power control signal if it is determined that the heating enable flag is true. The ambient temperature Te may be a temperature of a motor inside the compressor, a temperature at an inverter, or a temperature at a control chip of the compressor (e.g., a processor chip of executable instructions corresponding to the power control apparatus 10). The heating enable flag is preset by the master controller of the air conditioner according to the detected ambient temperature of the compressor. The main controller of the air conditioner can actively send a heating enabling mark to the electric control device when the air conditioner is started; the main controller of the air conditioner may transmit the modified heating enable flag to the power control device in the case of modifying the heating enable flag during operation of the air conditioner. The rotation controller 205 may also be implemented by a processor executing corresponding codes. The pulse width modulation unit 207 may be an optional component of the power control device 10.
In the present disclosure, the power closed-loop controller performs closed-loop control of heating power using a negative feedback principle such that a deviation of preset heating power from actual heating power is within a predetermined range, and if necessary, the deviation is made as small as possible. By way of example, the closed loop control means here may be: PI (proportional integral) control, adaptive control, ADRC (active disturbance rejection control), self-learning algorithms, and the like. For example, the power closed-loop controller generates a power control signal for closed-loop controlling the actual heating power based on the preset heating power and the actual heating power using a self-learning algorithm. The PI algorithm is preferably used for power closed loop control.
The power closed loop controller of the present disclosure may be implemented by supplementing the controller of the motor of an existing compressor with control logic. Existing motor controllers control the rotation of the motor based on torque. For example, a controller of the motor generates a pulse width modulated signal that controls an inverter based on the required torque to control rotation of the motor. Similarly, considering the direct correspondence of torque to current, according to one embodiment of the present disclosure, a pulse width modulation signal for controlling an inverter may be generated based on a required current to control heating power, and thus, some control logic may be shared with torque control, wherein the required current is related to a preset heating power and an actual heating power. More specifically, the power closed loop controller may determine a required current indication associated with the required current from the power error using a PI algorithm in the present embodiment, and the pulse width modulation unit generates a pulse width modulation signal for controlling the heating power based on the required current indication. Fig. 4 illustrates a block diagram of an example motor control structure, according to one embodiment of this disclosure. The power closed loop controller 430 includes a difference calculation unit 401 and a PI controller 403. The difference calculation unit 401 calculates a difference Δp between the preset heating power Ps and the actual heating power Pa, which may be supplied by the power determination unit 101. The PI controller 403 determines the required current i_dem to be set in order to reach the preset heating power Ps for the motor of the compressor based on the difference Δp, and generates a required current indication ins_i associated with the required current i_dem. The pulse width modulation unit 470 includes a current distribution unit 405, a current controller 407, a first conversion unit 409, a pulse width modulation signal generation unit 411, and a second conversion unit 413. The current distribution unit 405 determines a d-axis required current id_dem about a d-axis (straight axis) and a q-axis required current iq_dem about a q-axis (quadrature axis) based on the required current indication ins_i, wherein the quadrature-direct axis coordinate system rotating with the magnetic field is a conventional concept in the control theory of the permanent magnet synchronous motor, and will not be described herein. The current controller 407 determines the d-axis required voltage vd_dem, the q-axis required voltage vq_dem based on the d-axis required current id_dem, the q-axis required current iq_dem, the d-axis actual current id_a, and the q-axis actual current iq_a. The first conversion unit 409 determines the α -axis required voltage vα_dem, the β -axis required voltage vβ_dem based on the motor angular speed ω, the d-axis required voltage vd_dem, and the q-axis required voltage vq_dem. The stationary α - β axis coordinate system with α -axis and β -axis is a conventional concept in the control theory of the permanent magnet synchronous motor, and will not be described here. The pulse width modulation signal generation unit 411 generates the pulse width modulation signal PWM based on the α -axis required voltage vα_dem, the β -axis required voltage vβ_dem. Inverter 209 provides power to motor M under control of pulse width modulated signal PWM, wherein a characteristic parameter of the power includes three phase currents Ia, ib, ic. The second conversion unit 413 converts the three-phase currents Ia, ib, ic into a d-axis actual current id_a and a q-axis actual current iq_a based on the electrical angle θ of the motor. In this embodiment, the indication in_i may be regarded as a power control signal, wherein the combination of the difference calculation unit and the PI controller corresponds to a power closed loop controller. It will be appreciated that in another example, the combination of the power closed loop controller 430 and the pulse width modulation unit 470 may be considered a power closed loop controller. Accordingly, the pulse width modulation signal PWM may be regarded as a power control signal.
Fig. 5 shows test results of controlling heating power using the power control device according to one embodiment of the present disclosure. In fig. 5, (a) and (b) are test results of the #1 compressor, and preset heating powers Ps are 10W and 50W, respectively; (c) (d) the test result of the #2 compressor, wherein the preset heating power Ps is respectively 10W and 50W; pa is the actual heating power, where the test ends and the power is turned off resulting in a sharp drop in Pa at the end of each curve. It can be seen that the actual heating power Pa rapidly approaches the preset heating power Ps in the 4 test result curves, and Pa is well stabilized around Ps as time passes.
In one embodiment, the power closed-loop controller generates a power control signal Sp for closed-loop controlling the actual heating power Pa based on the preset heating power Ps and the actual heating power Pa using a PI algorithm. Further, the power closed-loop controller generates a power control signal Sp for closed-loop controlling the actual heating power Pa with the preset heating power Ps as a reference based on a difference between the preset heating power Ps and the actual heating power Pa using a PI algorithm. The PI algorithm may be configured such that the absolute value of the difference between the preset heating power Ps and the actual heating power Pa is less than 10% of the preset heating power Ps. More preferably, the PI algorithm may be configured such that the difference between the preset heating power Ps and the actual heating power Pa is substantially zero. The PI algorithm may be configured such that the absolute value of the difference between the preset heating power Ps and the actual heating power Pa is less than 8W, for example, such that the difference is maintained within ±5W.
In one embodiment of the present disclosure, the pulse width modulation unit is a component of the power control device. The pulse width modulation unit is connected with the power closed-loop controller to generate a pulse width modulation signal PWM based on the power control signal Sp. The pulse width modulation unit may be implemented by a processor executing corresponding code. The pulse width modulation unit may generate the pulse width modulation signal based on the power control signal such that a rotor of the motor to which the heating power is supplied remains stationary.
In one embodiment, the pulse width modulation may be Space Vector Pulse Width Modulation (SVPWM).
In one embodiment, the pulse width modulation may be a discontinuous vector modulation mode to reduce the number of switching tubes operated to reduce losses and improve the efficiency of stator heating.
The manner of determining the actual heating power is described below.
As one example, the actual heating power of the present disclosure may be determined using subtracting inverter power consumption from the input power of the inverter: pa=p I -P L ，P I Is the input power of the inverter, which can be determined based on the input voltage and input current of the inverter, P L Is the power consumption of the inverter itself. Accordingly, the power determining unit may determine the actual heating power based on the input voltage of the inverter, the input current of the inverter, and the power consumption of the inverter.
The power consumption of the inverter mainly comes from: the power consumption of switching transistors (e.g., IGBTs, insulated gate bipolar transistors) in the inverter and the power consumption of freewheeling diodes in the inverter. Thus, in one example, P may be determined based on device parameters of the switching transistor, freewheeling diode, characterization parameters of the pulse width modulated signal PWM (switching frequency, duty cycle, etc.), characteristics of the output current/voltage L . The power consumption of the switching transistor includes steady-state power consumption per switching and switching power consumption per switching. The power consumption of the flywheel diode includes steady-state power consumption and recovery power consumption. Accordingly, the power determining unit may determine the power consumption of the inverter based on the device parameters of the switching transistor and the freewheel diode included in the inverter. The manner of determining the power consumption may be embedded in the control code of the power control device, preferably the device parameters may be set to variables, in order toThe manufacturer, maintenance personnel or user makes appropriate adjustments or selections depending on the actual situation. For reference, fig. 6 shows an exemplary formula for calculating the power consumption of the inverter, wherein the switching transistor is an IGBT, and "p.f." represents a power factor.
As one example, the actual heating power Pa may be determined by a look-up table. In one embodiment, the queried table is an inverter power consumption table that includes an inverter output current field and an inverter power consumption field to determine a respective power consumption of the inverter based on the detected inverter output current. The power consumption table may be stored in a nonvolatile memory. For example, the correspondence of the output current and the power consumption may be determined as follows: before the actual heating power is controlled in a closed loop manner, the power control device controls the on-off state of a switching device of the inverter by controlling a modulation pulse width signal, current with different values is injected into a stator winding of a motor of the compressor on line, real-time input power and real-time output power of the inverter are determined, corresponding power consumption of the inverter under the current with different values is determined based on the determined real-time input power and real-time output power, and an inverter power consumption table stored in a nonvolatile memory (such as EEPROM) is updated based on the determined corresponding power consumption. The nonvolatile memory may be a component of the power control device. Using the detected output current to look up a power consumption table to obtain P L Thereby based on P L And P I The actual heating power Pa is obtained. Accordingly, the power determining unit may determine the power consumption of the inverter by looking up a power consumption table related to the power consumption of the inverter based on the output current of the inverter. In one variation, the power consumption table may be written to a nonvolatile memory of the power control device at a manufacturing stage of the power control device, and the power consumption table is not updated by a user at a use stage. In another modification, the power consumption table is updated at intervals of a predetermined long period of time, instead of updating the power consumption table each time before the closed-loop control is started up to the actual heating power. It can be appreciated that on-line updating of the power consumption table each time before starting the closed-loop control of the actual heating power is advantageous to ensure the accuracy of the actual heating power. To improve universality of power consumption table, power is increasedFlexibility of control, the power consumption table may also include further fields, such as: duty cycle, switching frequency and/or input dc voltage V of PMW DC Etc.
As one example, the actual heating power Pa may be determined by a power consumption function. And (3) offline detecting the target inverter to determine the output current and the corresponding power consumption of the target inverter, and fitting a power consumption curve related to the current by using a least square method to obtain a fitted power consumption function. Using the detected output current and the fitted power consumption function to obtain P L Thereby based on P L And P I The actual heating power Pa is obtained. Accordingly, the power determining unit may determine the power consumption of the inverter based on the output current of the inverter and a power consumption function of the inverter. The power consumption function may include further parameters such as: input DC voltage V DC And/or ambient temperature, etc.
As one example, the actual heating power Pa may also be determined based on the output current and the output voltage of the inverter.
Alternatively, the actual heating power Pa may be determined directly using the output current and the output voltage of the inverter, for example: pa=va+vb+ib+vc Ic.
Alternatively, the actual heating power Pa may be determined indirectly using the output current and the output voltage of the inverter: actual alpha-axis current I based on alpha-beta axis coordinate system α Actual beta-axis current I β Actual alpha-axis voltage V α Actual beta-axis voltage V β The actual heating power is determined.
For example: pa=v α *I α +V β *I β Wherein:
accordingly, the power determining unit may determine the actual heating power based on the output current and the output voltage to the inverter.
In one embodiment, the actual heating power Pa may be determined based on the input power of the inverter and the driving efficiency η of the inverter: pa=η×v DC *I DC . Accordingly, the power determining unit may determine the actual heating power based on the input power of the inverter and the driving efficiency of the inverter. The driving efficiency can be determined by experiments. The driving efficiency is related to the operating condition of the inverter. The drive efficiency can thus be stored in a nonvolatile memory in relation to the operating conditions of the inverter in order to determine the actual heating power.
In the method of determining the actual heating power, it is preferable to calculate the heating power directly using the output current and the output voltage of the inverter. In this way, the device power consumption can be eliminated from consideration when determining the actual heating power, thereby being beneficial to obtaining accurate actual heating power. Accurate heating power is advantageous in that closed loop control can keep the output power and preset heating power close enough. In one example, the output voltage of the inverter may be based on the PWM duty cycle and V DC To be determined, or by direct measurement.
The power control device of the present disclosure may be further configured to select an appropriate electrical angle of the motor when the heating power is supplied such that the motor is uniformly heated, wherein the pulse width modulation unit is configured to use space vector pulse width modulation such that the current of each phase winding may be adjusted. Fig. 7 shows an electrical angle setting of a motor according to one embodiment of the present disclosure, wherein pa=50w, an arrow near the winding indicates a current direction, the electrical angle θ is set to 30 ° in fig. 7 (a), and the electrical angle θ is set to 0 ° in fig. 7 (b); both settings may be used to generate 50W of heating power. In providing the heating power, the power closed-loop controller of the electric power control device may be configured to configure the electric angles of the motor so that the heating powers of the respective windings approach each other or reduce the maximum current flowing through the single stator winding in consideration of the preset heating power, so as to cause the motor to be heated uniformly. This may reduce wear on the individual windings, increasing the life of the motor.
The present disclosure also provides an air conditioning system. The air conditioning system is described below with reference to fig. 8. Fig. 8 illustrates a block diagram of an example air conditioning system 800, according to one embodiment of this disclosure. The air conditioning system 800 includes an indoor unit 81 and an outdoor unit 82. The indoor unit 81 includes a main controller 811 that controls the operation of the outdoor unit 82. The outdoor unit 82 includes a compressor 821. The compressor 821 includes the power control device 10, the inverter 209, and the motor M. As described with respect to fig. 1, the power control device 10 controls the inverter controlled by the pulse width modulated signal to supply heating power to heat the compressor to the windings of the stator of the motor of the compressor. The power control device 10 also receives power information about the inverter. The power control device 10 may include a power determination unit, a power closed loop controller, and a pulse width modulation unit. Although the power control device, inverter, are shown as part of the compressor in fig. 8, they may be discrete. For example, the power control device and the inverter as a driving controller of the compressor can be independently produced and sold. The same type of compressor may have a variety of drive controllers available for selection.
The present disclosure also provides a power control method. The method is used for controlling an inverter controlled by a pulse width modulation signal to provide heating power for heating a compressor to windings of a stator of a motor of the compressor. The power control method includes: determining a power of the heating power as an actual heating power based on the power information related to the inverter; and generating a power control signal for closed-loop controlling the actual heating power with the preset heating power as a reference based on the preset heating power and the actual heating power. The power control method is further described below with reference to fig. 9. Fig. 9 illustrates an exemplary flowchart of a power control method 90 according to one embodiment of the present disclosure. The power control method 90 is used to control an inverter controlled by a pulse width modulated signal to provide heating power to heat a motor of the compressor to windings of a stator of the compressor. After the air conditioning system is powered up and started, a heating enable flag Fm may be set according to the ambient temperature and the power control method 90 may be invoked. In step S901, it is determined whether the heating enable flag Fm is "true". In the case where the determination is "no," the method 90 is exited; accordingly, the main controller can determine whether to immediately start the standard cooling mode or the standard heating mode based on the instruction of the user, and immediately start the rotation of the compressor as required. In case the determination result is yes, step S903 is performed to generate an initial power control signal to control the inverter to inject an initial heating current into the stator winding of the motor of the compressor. For safety reasons, the initial power control signal may be configured such that an excessive initial heating current is avoided. In step S905, the power of the heating power is determined as the actual heating power Pa based on the power information about the inverter. In step S907, a power control signal Sp (e.g., ins_i or PWM) for closed-loop controlling the actual heating power with the preset heating power as a reference is generated based on the preset heating power Ps and the actual heating power Pa to control the inverter to inject a heating current into the stator windings. In step S909, it is determined whether the heating enable flag Fm is "true". If the determination is yes, the process returns to step S905, otherwise, the method 90 ends. The preset heating power Ps may vary during execution of the method 90. The method 90 may be implemented by execution of code from a memory by a processor. Reasonable variations of method 90 are possible. For example, step S909 may be performed once every several times step S907 is performed. Step S901 may be omitted if the main controller has confirmed that the compressor needs to be heated before invoking the method 90; in addition, step S909 may be replaced by checking whether or not to continue the stator heating by interacting with the main controller. For another example, the main controller sends the preset heating power to the power control device, the power control device closed-loop controls the actual heating power based on the received preset heating power, and the power control device stops stator heating in response to receiving the preset heating power having a value of "0", i.e., exits the method 90. Preferably, a power control signal for closed-loop controlling the actual heating power with the preset heating power as a reference is generated based on a difference between the preset heating power and the actual heating power using a PI algorithm. The power control method 90 corresponds to the power control apparatus of the present disclosure, and reference may be made to the description of the power control apparatus for further details of the method 90.
One aspect of the present disclosure provides a storage medium having a program stored thereon that is executed by a processor to control an inverter controlled by a pulse width modulated signal to provide heating power to heat a compressor to windings of a stator of a motor of the compressor. The program includes the following processing: determining a power of the heating power as an actual heating power based on the power information related to the inverter; and generating a power control signal for closed-loop controlling the actual heating power with the preset heating power as a reference based on the preset heating power and the actual heating power.
The present disclosure also provides an electrical control device for controlling an inverter controlled by a pulse width modulated signal to provide heating electrical energy to heat a compressor to windings of a stator of a motor of the compressor. An exemplary description is made below with reference to fig. 10. Fig. 10 shows a block diagram of a power control device 1000 according to one embodiment of the present disclosure. The power control device 1000 includes: a memory 1001 having instructions stored thereon; and one or more processors 1003, the one or more processors 1003 being capable of communicating with the memory to execute instructions retrieved from the memory, and the instructions causing the one or more processors to: determining a power of the heating power as an actual heating power based on the power information related to the inverter; and generating a power control signal for closed-loop controlling the actual heating power with the preset heating power as a reference based on the preset heating power and the actual heating power.
The power control device and the power control method of the present disclosure have at least one of the following advantages: the control precision of the heating power of the stator heating is improved; the motor is prevented from being damaged; the dependence on motor parameters is low; the applicability is wide; the safety of the system is improved; the reliability of the system is improved; easy to implement.
As described above, in accordance with the present disclosure, principles are provided for implementing stator heating using power closed loop control. It is to be noted that effects of aspects of the present disclosure are not necessarily limited to the above-described effects, and any of the effects shown in the present specification or other effects that can be understood from the present specification may be achieved in addition to or instead of the effects described in the preceding paragraphs.
While the invention has been disclosed in the context of specific embodiments thereof, it will be appreciated that those skilled in the art may devise various modifications, including combinations and substitutions of features between embodiments, as appropriate, within the spirit and scope of the appended claims. Such modifications, improvements, or equivalents are intended to be included within the scope of this invention.
It should be emphasized that the term "comprises/comprising" when used herein is taken to specify the presence of stated features, elements, steps or components, but does not preclude the presence or addition of one or more other features, elements, steps or components.
Furthermore, the methods of the embodiments of the present invention are not limited to being performed in the temporal order described in the specification or shown in the drawings, but may be performed in other temporal orders, in parallel, or independently. Therefore, the order of execution of the methods described in the present specification does not limit the technical scope of the present invention.
Claims (17)
1. An electric power control apparatus for controlling an inverter controlled by a pulse width modulation signal to supply heating electric power for heating a compressor to windings of a stator of a motor of the compressor, comprising:
a power determining unit that determines a power of the heating electric energy as an actual heating power based on power information related to the inverter; and
a power closed loop controller that generates a power control signal based on a preset heating power and the actual heating power;
the power control signal is a control signal for controlling the actual heating power in a closed loop mode by taking the preset heating power as a reference.
2. The power control device of claim 1, wherein the power closed-loop controller is configured to generate the power control signal that closed-loop controls the actual heating power based on the preset heating power and the actual heating power using a self-learning algorithm.
3. The power control apparatus of claim 1, wherein the power closed-loop controller is configured to generate the power control signal that closed-loop controls the actual heating power based on the preset heating power based on a difference between the preset heating power and the actual heating power using a PI algorithm.
4. The power control device according to claim 1, characterized by further comprising:
and a pulse width modulation unit that generates the pulse width modulation signal based on the power control signal.
5. The power control device of claim 4, wherein the pulse width modulation unit is configured to generate the pulse width modulation signal based on the power control signal such that a rotor of the motor to which the heating electrical energy is supplied remains stationary.
6. The power control device of claim 4, wherein the power closed loop controller is configured to generate a required current indication as the power control signal based on a difference between the preset heating power and the actual heating power using a PI algorithm and the pulse width modulation unit is configured to generate the pulse width modulation signal based on the required current indication, a d-axis actual current, and a q-axis actual current;
wherein the d-axis actual current and the q-axis actual current are obtained by performing coordinate transformation on three-phase currents of the output of the inverter.
7. The power control apparatus of claim 1, wherein the compressor is an electric load for an outdoor unit of an air conditioner.
8. The power control device of claim 7, wherein the power controller is configured to generate the power control signal if it is determined that a heating enable flag is "true"; and is also provided with
The heating enable flag is set by a main controller of the air conditioner according to the detected ambient temperature of the compressor.
9. The power control apparatus according to claim 1, wherein the power determination unit is configured to: the actual heating power is determined based on an input voltage of the inverter, an input current of the inverter, and power consumption of the inverter.
10. The power control device of claim 9, wherein the power control device is configured to: before the actual heating power is closed-loop controlled, controlling the inverter to inject currents of different values into windings of a stator of a motor of the compressor, determining respective real-time input power and respective real-time output power of the inverter, determining respective power consumption of the inverter at the currents of the different values based on the respective determined real-time input power and respective real-time output power, and updating an inverter power consumption table stored in a nonvolatile memory based on the determined respective power consumption.
11. The power control apparatus according to claim 9, wherein the power determination unit is configured to: and determining the power consumption of the inverter by looking up a table based on the output current of the inverter.
12. The power control apparatus according to claim 9, wherein the power determination unit is configured to: the power consumption of the inverter is determined based on an output current of the inverter and a power consumption function of the inverter.
13. The power control apparatus according to claim 9, wherein the power determination unit is configured to: the power consumption of the inverter is determined based on device parameters of a switching transistor and a freewheeling diode included in the inverter.
14. The power control apparatus according to claim 4, wherein the power determination unit is configured to: determining the actual heating power according to the output voltage of the inverter and the output current of the inverter; and is also provided with
The output voltage of the inverter is determined according to the duty cycle of the pulse width modulated signal and the output voltage of the dc power supply of the inverter or by direct measurement.
15. The power control device according to claim 4, wherein the pulse width modulation unit is configured to generate the pulse width modulation signal in consideration of an electrical angle of the motor, and the pulse width modulation unit configures the electrical angle of the motor so that the motor is heated uniformly.
16. The power control apparatus according to claim 1, wherein the power determination unit is configured to: the actual heating power is determined based on an input power of the inverter and a driving efficiency of the inverter.
17. An electric power control method for controlling an inverter controlled by a pulse width modulation signal to supply heating electric power for heating a compressor to windings of a stator of a motor of the compressor, comprising:
determining a power of the heating power as an actual heating power based on power information about the inverter; and
generating a power control signal based on a preset heating power and the actual heating power;
the power control signal is a control signal for controlling the actual heating power in a closed loop mode by taking the preset heating power as a reference.
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| CN202210655315.4A CN117254720A (en) | 2022-06-10 | 2022-06-10 | Power control device and power control method |
| PCT/CN2023/099311 WO2023237086A1 (en) | 2022-06-10 | 2023-06-09 | Electric control apparatus and electric control method |
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| CN202210655315.4A CN117254720A (en) | 2022-06-10 | 2022-06-10 | Power control device and power control method |
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| CN109217776B (en) * | 2018-09-27 | 2020-10-20 | 深圳市英威腾电气股份有限公司 | Heating method and device of motor and frequency converter |
| CN112133987A (en) * | 2019-06-25 | 2020-12-25 | 北京新能源汽车股份有限公司 | Heating control method and device for power battery |
| CN112297771B (en) * | 2019-07-31 | 2022-05-20 | 北京新能源汽车股份有限公司 | Permanent magnet synchronous motor heat management control method and device and automobile |
| CN112550062B (en) * | 2019-09-25 | 2022-03-18 | 比亚迪股份有限公司 | Cooperative control method and device for energy conversion device, storage medium and vehicle |
| CN110995099B (en) * | 2019-12-25 | 2021-04-27 | 浙江吉智新能源汽车科技有限公司 | Motor heating control method, controller and system based on look-up table and closed-loop control |
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