WO2014176947A1 - Heat pump water heater and control method therefor - Google Patents

Heat pump water heater and control method therefor Download PDF

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Publication number
WO2014176947A1
WO2014176947A1 PCT/CN2014/072637 CN2014072637W WO2014176947A1 WO 2014176947 A1 WO2014176947 A1 WO 2014176947A1 CN 2014072637 W CN2014072637 W CN 2014072637W WO 2014176947 A1 WO2014176947 A1 WO 2014176947A1
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WO
WIPO (PCT)
Prior art keywords
winding
compressor
connected
heat pump
plurality
Prior art date
Application number
PCT/CN2014/072637
Other languages
French (fr)
Chinese (zh)
Inventor
寇颖举
李绍斌
曹浩
史帆
柳飞
袁明征
Original Assignee
珠海格力电器股份有限公司
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Publication date
Priority to CN201310157091.5A priority Critical patent/CN104121702B/en
Priority to CN201310157091.5 priority
Application filed by 珠海格力电器股份有限公司 filed Critical 珠海格力电器股份有限公司
Publication of WO2014176947A1 publication Critical patent/WO2014176947A1/en

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT GENERATING MEANS, IN GENERAL
    • F24H9/00Details
    • F24H9/20Arrangement or mounting of control or safety devices or methods
    • F24H9/2007Arrangement or mounting of control or safety devices or methods for water heaters
    • F24H9/2014Arrangement or mounting of control or safety devices or methods for water heaters for heaters using electrical energy supply
    • F24H9/2021Storage heaters
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT GENERATING MEANS, IN GENERAL
    • F24H4/00Fluid heaters using heat pumps
    • F24H4/02Liquid heaters
    • F24H4/04Storage heaters

Abstract

Disclosed is a heat pump water heater, comprising: a water tank; a detection unit used for detecting the temperature of water in the water tank to acquire the detected water temperature; a compressor, a motor coil of which has a multi-level winding, where a resistance value of the n-th level of the winding of the multi-level winding is less than that of the (n-1)-th level of the winding of the multi-level winding; a control unit which is connected to both the detection unit and the compressor, and is used for finding a winding corresponding to the detected water temperature to acquire a p-th level of the winding, and controlling the compressor to operate using the p-th level of the winding. Also disclosed is a control method for the above-mentioned heat pump water heater.

Description

 Heat pump water heater and control method thereof

TECHNICAL FIELD The present invention relates to the field of water heaters, and in particular to a heat pump water heater and a control method thereof. BACKGROUND OF THE INVENTION The overall unit performance of a heat pump water heater is reduced as the temperature of the hot water increases, that is, the higher the water temperature, the lower the performance of the heat pump water heater. Especially for the heat pump water heater products with fixed-frequency compressors, because the motor turns of fixed-frequency compressors are fixed, the windings are fixed, the speed is also fixed, and the compressor frequency or speed cannot be adjusted according to the operating conditions of the system under different water temperature conditions. In the high water temperature stage, the performance of the heat pump water heater will be significantly reduced, resulting in a decrease in the overall performance of the heat pump water heater during the entire heating water process. In view of the problem that the performance of the heat pump water heater in the related art decreases with the increase of the water temperature, an effective solution has not been proposed yet. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a heat pump water heater and a control method thereof to solve the problem that the performance of the heat pump water heater decreases with the increase of water temperature in the prior art. In order to achieve the above object, according to an aspect of the invention, a heat pump water heater is provided, comprising: a water tank; a detecting unit for detecting a water temperature in the water tank to obtain a detected water temperature; and a motor coil of the compressor and the compressor Stage winding, wherein the resistance of the nth winding of the multi-stage winding is smaller than the resistance of the n-1th winding of the multi-stage winding, n is a natural number of 2 or more; and the control unit, and the detecting unit and the compressor are both Connected to find a winding corresponding to the detected water temperature, obtain a p-th winding, and control the compressor to operate using the p-th winding, wherein p is a natural number, l ≤ p ≤ n, The heat pump water heater stores a correspondence between different water temperature intervals and winding stages, and the higher the average water temperature in the water temperature interval, the larger the corresponding number of winding stages. Further, the motor coil has a static contact and a plurality of movable contacts, and the static contact is connected with the movable contact of the plurality of movable contacts to form an nth winding, the static contact and the plurality of dynamic contacts The moving contacts in the point are connected to form an n-1th winding, wherein the control unit is used to control the static contact to be connected with one of the plurality of moving contacts, and the control unit controls the static contact When connected to the moving contact j P of the plurality of moving contacts, the compressor operates with the p-th winding. Further, the control unit includes: a plurality of first switches, wherein a first switch is connected between each of the static contact and the plurality of movable contacts; and the controller, the detecting unit and the plurality of The control ends of the first switch are connected to each other for controlling the on and off states of the plurality of first switches, wherein the controller controls the first switch between the static contact and the movable contact jp to be closed, the static contact is moving The contacts jp are connected. Further, the heat pump water heater further includes: a capacitor unit, wherein each of the plurality of windings has a capacitor unit connected in parallel, and the capacitance of the nth capacitor unit is greater than the capacitance of the n-1th capacitor unit, the nth capacitor The unit is a capacitor unit connected in parallel on the nth winding, and the n-1th capacitor unit is a capacitor unit connected in parallel on the n-1th winding. Further, the capacitor unit includes: n capacitors, wherein n capacitors are sequentially connected in series; and a plurality of second switches, wherein at least n-1 of the n capacitors are connected in parallel with a second switch, the controller and the controller The control ends of the plurality of second switches are all connected to control the switching states of the plurality of second switches. Further, the capacitor unit includes: n capacitors, wherein any two of the n capacitors are connected in parallel; and a plurality of third switches, wherein at least n-1 of the n capacitors are connected in series The three switches are connected to the control ends of the plurality of third switches for controlling the switching states of the plurality of third switches. In order to achieve the above object, according to another aspect of the present invention, there is provided a control method of a heat pump water heater including a water tank and a compressor, wherein a motor coil of the compressor has a multi-stage winding, and a multi-stage winding The resistance of the n-stage winding is smaller than the resistance of the n-1th winding of the multi-stage winding, and n is a natural number of 2 or more. The control method includes: Step S11: detecting the water temperature in the water tank to obtain the detected water temperature; Step S12: Finding a winding corresponding to the detected water temperature to obtain a p-th winding, wherein p is a natural number, l≤p≤n, and a correspondence between different water temperature intervals and winding stages is stored in the heat pump water heater, and And the higher the average water temperature in the water temperature interval, the corresponding number of the winding stages is greater; and step S13: controlling the compressor to operate using the p-th stage winding, and returning to step S11. Further, finding a winding corresponding to the detected water temperature, obtaining the p-th winding comprises: finding a preset temperature range in which the detected water temperature is located; and obtaining a winding corresponding to the found preset temperature range to obtain a p-th winding. Further, the motor coil has a static contact and a plurality of movable contacts, and controlling the compressor to operate with the p-th winding includes: controlling the static contact to be connected with the movable contact j P of the plurality of movable contacts. Further, a first switch is connected between each of the static contact and the plurality of movable contacts, and the control static contact is connected with the movable contact j P of the plurality of movable contacts, including: The first switch between the stationary contact and the movable contact j P is closed. Further, a capacitor unit is connected in parallel to each of the windings of the multi-stage winding, wherein the capacitance value of the n-th capacitor unit is greater than the capacitance value of the n-1th capacitor unit, and the n-th capacitor unit is paralleled on the n-th winding The capacitor unit, the n-1th capacitor unit is a capacitor unit connected in parallel on the n-1th winding, and the control method further includes: controlling the compressor to use the pth capacitor unit while controlling the compressor to operate the pth winding In operation, the p-th capacitor unit is a capacitor unit connected in parallel on the p-th stage winding. The invention adopts a heat pump water heater comprising the following structure: a water tank; a detecting unit for detecting the water temperature in the water tank to obtain a detected water temperature; and a compressor, the motor coil of the compressor has a multi-stage winding, wherein the n-th winding of the multi-stage winding The resistance of the stage winding is less than the resistance of the n-1th winding in the multi-stage winding, n is a natural number of 2 or more; and the control unit is connected to the detection unit and the compressor for searching and detecting the water temperature The winding, the p-stage winding is obtained, and the compressor is controlled to operate with the p-th winding, wherein p is a natural number, l≤p≤n, and the correspondence between different water temperature intervals and winding stages is stored in the heat pump water heater. And, the higher the average water temperature in the water temperature range, the larger the number of winding stages. By setting the motor coil of the compressor to a multi-stage winding, and the resistance of the high-level winding is lower than the resistance of the lower-level winding, when the winding resistance of the compressor is large, the compressor passes through The current is small, the compressor is equivalent to a small motor, and conversely, the current passing through is large, the compressor is equivalent to a large motor, the resistance point of the optimal working point of the small motor is small, and the resistance of the optimal working point of the large motor is corresponding. The moment is large. In the work of heat pump water heaters, the higher the water temperature, the higher the resistance torque of the heat pump water heater. If the windings used by the compressor are unchanged, the operating state of the compressor deviates from its optimal operating point at high water temperature, resulting in efficiency. Decrease, by pre-storing the correspondence between the water temperature and the winding, determining the winding size to be used by the compressor according to the detected water temperature, and then controlling the compressor to operate according to the found winding, achieving the control pressure at a relatively low temperature. The compressor is operated with a large resistance winding, so that the compressor operates as a small motor, and the compressor is controlled to operate with a smaller resistance winding at a relatively high temperature to upgrade the compressor to a large motor, thereby realizing The compressor is controlled to follow the change of water temperature to maintain the optimal working point, thereby improving the operating efficiency of the compressor, and solving the problem that the performance of the heat pump water heater decreases with the increase of water temperature in the prior art, thereby achieving the improvement of the heat pump. The overall performance of the water heater. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in FIG. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: FIG. 1 is a schematic diagram of a motor coil of a heat pump water heater having two stages of windings according to an embodiment of the present invention; FIG. 2 is a control circuit diagram of winding series control of the motor coil shown in FIG. In the prior art, the compressor uses the first-stage winding operation alone and the "efficiency-torque curve" when operating the second-stage winding alone; 4 is a schematic diagram of "efficiency-torque curve" of a compressor of a heat pump water heater according to an embodiment of the present invention; FIG. 5 is a schematic diagram of a motor coil having a three-stage winding of a heat pump water heater according to an embodiment of the present invention; FIG. 7 is a first preferred control circuit diagram for controlling the number of winding stages of the motor coil shown in FIG. 5; FIG. 8 is a view of the first preferred control circuit for controlling the number of windings of the motor coil shown in FIG. A second preferred control circuit diagram for the winding stage control of the illustrated motor coil; and FIG. 9 is a flow chart of a method of controlling a heat pump water heater in accordance with an embodiment of the present invention. The specific lung type needs to be described that the features in the embodiments and the embodiments in the present application can be combined with each other without conflict. The invention will be described in detail below with reference to the drawings in conjunction with the embodiments. The embodiment of the present invention provides a heat pump water heater. The heat pump water heater provided by the embodiment of the present invention is specifically described as follows: The heat pump water heater provided by the embodiment of the present invention mainly includes a water tank, a detecting unit, a compressor, and a control unit, wherein The detecting unit is used for detecting the temperature of the water in the water tank, and may be a thermocouple or a thermal resistance type temperature sensor or a temperature sensing temperature pack. The motor coil of the compressor has multiple windings, the resistance of the nth winding of the multi-stage winding is smaller than the resistance of the n-1th winding of the multi-stage winding, n is a natural number of 2 or more, SP, the winding of the high level The resistance is less than the resistance of the lower level winding. The control unit is connected to the detection signal output end of the detecting unit and the electric control end of the compressor, and is configured to find a winding corresponding to the detected water temperature detected by the detecting unit, obtain a p-stage winding, and control the compressor to adopt The p-stage winding operates, wherein p is any natural number of 1 or more and n or less, and the correspondence between different water temperature intervals and the number of winding stages is stored in the heat pump water heater, and the average water temperature in the water temperature interval is higher, The larger the number of stages of the corresponding winding, that is, if the detected water temperature is high, the found p-stage winding is a high-level (p-value) winding, and the control compressor uses a winding with a small resistance. Operation, if the detected water temperature is low, the p-stage winding found is a low-level (lower p-value) winding, and the control compressor is operated with a winding with a large resistance. The heat pump water heater of the embodiment of the invention sets the motor coil of the compressor into a multi-stage winding, and the resistance of the high-level winding is lower than the resistance of the low-level winding, when the winding resistance of the compressor is large The current passing through the compressor is small, the compressor is equivalent to a small motor, and conversely, the current passing through is large, the compressor is equivalent to a large motor, and the optimal operating point of the small motor corresponds to a small resistance torque. The optimum working point corresponds to a large resistance torque. In In the heat pump water heater work, the higher the water temperature, the higher the resistance torque of the heat pump water heater. If the winding used by the compressor does not change, the operating state of the compressor deviates from its optimal operating point at high water temperature, resulting in reduced efficiency. By pre-storing the correspondence between the water temperature and the winding, determining the winding size to be used by the compressor according to the detected water temperature, and then controlling the compressor to operate according to the found winding, achieving control compression at a relatively low temperature. The machine is operated with a large resistance winding, so that the compressor operates as a small motor, and the compressor is controlled to operate with a smaller resistance winding at a relatively high temperature to upgrade the compressor to a large motor, thereby realizing The compressor is controlled to maintain the optimal operating point following the change of the water temperature, thereby improving the operating efficiency of the compressor, and solving the problem that the performance of the heat pump water heater decreases with the increase of the water temperature in the prior art, thereby achieving the improvement of the heat pump water heater. The overall performance effect. Specifically, FIG. 1 is a schematic diagram of a motor coil having two stages of windings, taking the motor coil having two stages of windings shown in FIG. 1 as an example to further illustrate the heat pump water heater provided by the embodiment of the present invention. As shown in Figure 1, the motor coil with two stages of windings has a stationary contact j. And two moving contacts _, ) 2, static contact j. When connected to the moving contact, the first winding of the motor coil is formed, and the stationary contact j is formed. When connected to the movable contact j 2 , the second winding of the motor coil is formed. For the case of the two-stage winding, in the heating process of the heat pump water heater, the control unit generally controls the compressor to first adopt the first-stage winding. Operation, when the water temperature rises to a preset temperature value, the compressor is controlled to operate with the second-stage winding. If the water temperature drops again, the compressor is controlled to be operated by the second-stage winding. The primary winding operates, wherein the control unit is connected to the movable contact by controlling the static contact jo to achieve the purpose of controlling the compressor to operate with the first stage winding, by controlling the static contact jo and the movable contact j 2 Connected to achieve the purpose of controlling the compressor to operate with the second stage winding. Further, the control unit can control the connection relationship between the stationary contact jo and the movable contact _, j 2 through the electrical control circuit diagram shown in FIG. 2, as shown in FIG. 2, the control unit includes a controller ( Not shown in the figure) and a plurality of first switches KF11, KF12... KFln, for a motor coil having two windings, the number of first switches is two, and one first switch KF11 is connected to static Between the contact j Q and the movable contact ^, the other first switch KF12 is connected between the stationary contact jo and the movable contact j 2 , and the control ends of the first switch KF11 and the first switch KF12 are connected to the controller Connected, the controller is also connected to the detection signal output end of the detecting unit. When the water temperature detected by the detecting unit does not reach the preset temperature, the controller controls the first between the static contact jo and the movable contact _ή A switch KF11 is closed, and the first switch KF12 between the control static contact jo and the movable contact j 2 is opened, so that the compressor operates with the first-stage winding, and the water temperature detected by the detecting unit reaches a preset temperature. In this case, the controller controls the stationary contact j. The first switch KF11 between the movable contact and the movable contact is opened, and the first switch KF12 between the fixed contact jo and the movable contact j 2 is closed to operate the compressor with the second stage winding. Figure 3 shows the "efficiency" between the compressor efficiency and the optimum operating point when the compressor is operated with the first stage winding and the compressor is operated separately with the second stage winding. Torque curve "schematic diagram, Figure 4 shows the compressor efficiency and most when the control compressor is operated with the first stage winding and the second stage winding in sequence. The "efficiency-torque curve" between the resistance points corresponding to the good working point, the curve L1 in Fig. 3 shows the efficiency curve of the compressor using the first-stage winding alone. It can be seen that the compressor in the first half The efficiency is high, and the efficiency of the second half compressor is low. The curve L2 in Fig. 3 shows the efficiency curve of the compressor using the second-stage winding alone. It can be seen that the efficiency of the compressor in the first half is lower, and the efficiency of the compressor in the second half is relatively higher. The second half of the curve L1. Figure 4 is a graph showing the efficiency of the motor with double windings. It can be seen that the curve L3 uses the first stage winding in the first half and the second stage winding in the second half, so that the efficiency is higher than that of the single winding in the whole process. s efficiency. FIG. 5 is a schematic diagram of a motor coil having three stages of windings, taking the motor coil having the tertiary winding shown in FIG. 5 as an example to further illustrate the heat pump water heater provided by the embodiment of the present invention. As shown in FIG. 5, the motor coil having the three-stage winding has one static contact jo and three movable contacts _ j 2 j 3 , and when the stationary contact jo and the movable contact are connected, the motor coil is formed. The primary winding, when the stationary contact jo is connected to the movable contact j 2 , forms a second-stage winding of the motor coil, and a stationary contact j. When connected to the movable contact j 3 , the third-stage winding of the motor coil is formed. For the case of the three-stage winding, two preset temperature points Tqi and Tq 2 and three temperature intervals are generally set in the heat pump water heater [ Ί η Tqi ) [Tq Tq 2 ) and [Tq 2 T where Tq 2 >Tqi is the temperature of the cold water initially injected in the tank, the maximum temperature that can be achieved by heating the heat pump water heater, temperature range [T min Τ 3⁄41 Corresponding to the first-stage winding, the temperature interval [Τ Tq 2 ) corresponds to the second-stage winding, and the temperature interval [Tq 2 Τ^] corresponds to the third-stage winding. When the detected water temperature belongs to any of the temperature intervals [ Ί η Τ 3⁄41 ) At the temperature, the control compressor is operated with the first-stage winding. When the detected water temperature belongs to any temperature in the temperature interval [T qi Tq 2 ), the control compressor is operated with the second-stage winding, and when the detected water temperature belongs to the temperature interval [At any temperature in Tq T^, the control compressor is operated with a third-stage winding. During the continuous heating of the heat pump water heater, the water temperature in the water tank gradually rises, then the control unit generally controls the compressor to first operate with the first stage winding, when the water temperature rises to T qi (hereinafter referred to as the first preset temperature) When the control compressor is operated with the second-stage winding, and the water temperature continues to rise to Tq 2 (hereinafter referred to as the second preset temperature), the compressor is controlled to operate with the third-stage winding, that is, with the water temperature The rise of the compressor gradually controls the compressor to operate with a winding having a small resistance value. The control unit is connected to the movable contact by controlling the static contact jo to achieve the purpose of controlling the compressor to operate with the first stage winding. By controlling the static contact jo to be connected with the movable contact j 2 , the purpose of controlling the compressor to operate using the second-stage winding is achieved, and the control contact compression is achieved by controlling the static contact jo to be connected with the movable contact j 3 . The machine uses the third stage winding for the purpose of operation. Further, the control unit can control the connection relationship between the stationary contact jo and the movable contact _ j 2 j 3 through the electrical control circuit diagram shown in FIG. 6, as shown in FIG. 6, the control unit includes a controller (not shown) and a plurality of first switches KF11 KF12... KFln, for a motor coil having three windings, the number of first switches is three, and the first first switch KF11 is connected Between the stationary contact j Q and the movable contact ^, the second first switch KF12 is connected between the stationary contact jo and the movable contact j 2 , and the third first switch KF13 is connected to the stationary contact Jo and the movable contact j 3 , and the control ends of the three first switch KF11, the first switch KF12 and the first switch KF13 are connected to the controller, and the controller is also connected with the detection signal output end of the detecting unit Connecting, in the case that the water temperature detected by the detecting unit does not reach the first preset temperature, the controller controls the first switch KF11 between the static contact jo and the moving contact _ to close, control the static contact jo and the movable contact The first switch KF12 between j 2 is disconnected, the first switch KF13 between the control static contact jo and the movable contact j 3 is disconnected, so that the compressor operates with the first stage winding, and the detection unit detects When the water temperature reaches the first preset temperature but has not reached the second preset temperature, the controller controls the first switch KF11 between the static contact jo and the movable contact ^ to be disconnected, and the static contact jo and the movement are controlled. The first switch KF12 between the contacts j 2 is closed, and the first switch KF13 between the static contact jo and the movable contact j 3 is controlled to be disconnected, so that the compressor operates with the second-stage winding, and is detected by the detecting unit. When the water temperature reaches the second preset temperature, the controller controls the static contact jo and the movement A first switching point between ^ KF11 off control stationary contact and movable contact jo j 2 between the first switch OFF KF12, jo control stationary contact and movable contact of the first switch between the 3 j KF13 is closed so that the compressor operates with a third stage winding. Preferably, the heat pump water heater provided by the embodiment of the present invention further includes a capacitor unit, the number of the capacitor units is the same as the number of stages of the multi-stage winding, and one capacitor unit is connected in parallel to each of the first-stage windings, and the capacitance value of the n-th capacitor unit is greater than The capacitance value of the n-1th capacitor unit, the nth capacitor unit is a capacitor unit connected in parallel on the nth stage winding, the n-1th capacitor unit is a capacitor unit connected in parallel on the n-1th stage winding, SP, a high level winding The capacitance value of the capacitor unit connected in parallel is greater than the capacitance value of the capacitor unit connected in parallel on the lower level winding. The following is an example of a motor coil having a three-stage winding: FIG. 7 is a medium pressure of a heat pump water heater according to a preferred embodiment of the present invention. A first electrical control circuit diagram for controlling the compressor. In the preferred embodiment, the motor coil of the compressor has three stages of windings. As shown in FIG. 7, the capacitor unit includes three capacitors Cl, C2, and C3. And two second switches KF21, KF22, capacitor C1, capacitor C2 and capacitor C3 are connected in series, and the second switch KF21 and the second switch KF22 are respectively connected in parallel with the capacitor C1, the capacitor C2 and the electric Any two capacitors in the capacitor C3 (the second switch KF21 is connected in parallel to the capacitor C2, the second switch KF22 is connected in parallel to the capacitor C3), and the control terminals of the second switch KF21 and the second switch KF22 are further Both are connected to the controller. When the controller controls the second switch KF21 and the second switch KF22 to be disconnected, the capacitor C1, the capacitor C2 and the capacitor C3 form a first capacitor unit connected in parallel on the first stage winding, and the capacitor C1, the capacitor C2 and the capacitor C3 are connected in series. The capacitance value of the first capacitor unit is small. When the controller controls one of the second switch KF21 and the second switch KF22 to be closed and the other second switch is turned off, the capacitor C1, the capacitor C2 and the capacitor C3 constitutes a second capacitor unit connected in parallel on the second-stage winding, and the capacitance value of the second capacitor unit composed of a capacitor C1 and a capacitor C2 (or capacitor C3) connected in series is centered, when the controller controls the second switch KF21 and the second When the switch KF22 is closed, the capacitor C1, the capacitor C2 and the capacitor C3 form a third capacitor unit connected in parallel to the third-stage winding. The capacitance value of the third capacitor unit composed only of the capacitor CI is the largest, that is, when the water temperature does not reach the first preset temperature, the controller controls the second switch KF21 and the second switch KF22 to be disconnected, and simultaneously controls the static touch. The point j Q is connected to the movable contact ^ so that the compressor operates with the first capacitor of a smaller capacitance value while operating the first stage winding with a larger resistance value. When the water temperature reaches the first preset temperature but has not reached the second preset temperature, the controller controls one of the second switch KF21 and the second switch KF22 to be closed, and the other second switch is turned off, and simultaneously controlled The stationary contact jo is coupled to the movable contact j 2 such that the compressor operates with the second capacitor unit of the intermediate capacitance value while the second stage winding of the intermediate resistance is used. When the water temperature reaches a second preset temperature, the controller controls the second switch KF21 and KF22 second switch are closed, while controlling the movable contact and the stationary contacts jo j 3 are connected, so that a smaller compressor While the third-stage winding of the resistance is running, the third capacitor unit of a larger capacitance value is operated. The number of the second switches may also be the same as the number of capacitors, that is, each of the capacitors is connected in parallel with a second switch, and when the controller controls each of the second switches, and the second switches of FIG. 7 The control principle is the same, only need to ensure that at least one second switch is closed. In conjunction with the electrical control diagram shown in FIG. 7, the second switch connected in parallel on the capacitor C1 is always controlled to be closed. The capacitance values of the capacitor C1, the capacitor C2 and the capacitor C3 can be set according to the actual hardware design of the heat pump water heater and the operating conditions at the time of operation. Figure 8 is a second electrical control circuit diagram for controlling a compressor in a heat pump water heater in accordance with a preferred embodiment of the present invention. In the preferred embodiment, the motor coil of the compressor has three stages of windings as an example, as shown in Figure 8. As shown, the capacitor unit includes three capacitors Cl, C2, C3 and two third switches KF31, KF32, and any two of the capacitors C1, C2 and C3 are connected in parallel, and the third switch KF31 and the third switch KF32 respectively In series with any two of the capacitor C1, the capacitor C2 and the capacitor C3 (the third switch KF31 is shown in series with the capacitor C2, the third switch KF32 is connected in series with the capacitor C3), the third switch KF31 and the third switch The control terminals of the KF32 are also connected to the controller. When the controller controls the third switch KF31 and the third switch KF32 to be disconnected, the capacitor C1, the capacitor C2 and the capacitor C3 form a first capacitor unit connected in parallel on the first stage winding, and the first capacitor consisting only of the capacitor C1 The capacitance value of the unit is small. When the controller controls one of the third switch KF31 and the third switch KF32 to be closed and the other third switch is turned off, the capacitor C1, the capacitor C2 and the capacitor C3 are connected in parallel to be in the second The second capacitor unit on the winding of the stage, the capacitance value of the second capacitor unit composed of the capacitor C1 and the capacitor C2 (or the capacitor C3) being connected in parallel is centered, when the controller controls the third switch KF31 and the third switch KF32 to be closed, The capacitor C1, the capacitor C2 and the capacitor C3 form a third capacitor unit connected in parallel on the third-stage winding, and the capacitance value of the third capacitor unit composed of the capacitor C1, the capacitor C2 and the capacitor C3 in parallel is larger, that is, when the water temperature is not When the first preset temperature is reached, the controller controls the third switch KF31 and the third switch KF32 to be disconnected, and simultaneously controls the static contact jo and the moving contact _ to be connected, so that the compressor adopts a larger resistance value. First stage winding At the same time as the line, the smaller capacitance value is used. A capacitor unit operates. When the water temperature reaches the first preset temperature but has not reached the second preset temperature, the controller controls one of the third switch KF31 and the third switch KF32 to be closed, and the other third switch is turned off, and simultaneously controlled Static contact j. It is connected to the movable contact j 2 so that the compressor operates with the second capacitor unit of the intermediate capacitance value while the second stage winding of the intermediate resistance is used. When the water temperature reaches a second preset temperature, the controller controls the third switch KF31 and KF32 third switch are closed, while controlling the movable contact and the stationary contacts jo j 3 are connected, so that a smaller compressor While the third-stage winding of the resistance is running, the third capacitor unit of a larger capacitance value is operated. The number of the third switches may also be the same as the number of capacitors, that is, each capacitor is directly connected in series with a third switch, and the controller controls each of the third switches, and each of the third in FIG. The control principle of the switch is the same, only need to ensure that at least one third switch is closed. In combination with the electrical control diagram shown in Fig. 8, the third switch connected in series with the capacitor C1 is always controlled to be closed. The capacitance value of the capacitor C1, the capacitor C2 and the capacitor C3 can be set according to the actual hardware design of the heat pump water heater and the working condition of the operation. In this embodiment, the capacitance value of the capacitor C1 can be 25uF, the capacitor C2 and the capacitor C3. The capacitance value can be taken as 10uF. Since the winding resistance values used in the compressor operation are different, capacitors with different capacitance values are required to match, that is, the size of the motor matches the size of the capacitor, and the larger the motor, the required matching The larger the capacitance, the smaller the opposite. If the motor is switched from a small motor to a large motor, and there is no matching capacitor access circuit, the unit may not operate normally. The performance is as follows: If the unit is in the startup state, it may not start normally. If the unit is in normal operation, In operation, it may cause abnormal conditions such as poor operation and unstable current. In the heat pump water heater of the preferred embodiment of the present invention, by providing a capacitor unit corresponding to the winding level, the capacitor unit can function to buffer a large current during startup and stabilize the circuit during operation in electrical control of the heat pump water heater. The effect of improving the operational stability of the heat pump water heater is achieved. The first switch, the second switch and the third switch may each be a relay switch, and the switch contact of the relay switch as the first switch is connected between the static contact and the movable contact, and the switch of the relay switch as the second switch The contact is connected to the capacitor of FIG. 7. The switch contact of the relay switch as the third switch is connected to the capacitor of FIG. 8. The controller is connected to the control coil of the relay switch, and is controlled by controlling whether or not current flows in the control coil. The relay switch is turned on and off. It should be noted that, in the heat pump water heater provided by the embodiment of the present invention, the motor coil of the compressor may be four or more stages. For the motor coil having four or more windings, the composition of the motor coil and FIG. 1 and FIG. 5 The motor coil having the two-stage winding and the third-stage winding shown in the difference is different in that the number of moving contacts is increased to four or more. The electrical control schematic of the compressor differs from the electrical control schematic shown in Figures 2 and 6 to 8. The point is that the number of the first switch, the second switch, and the capacitor are correspondingly increased according to actual needs. I will not go into details here. The embodiment of the present invention further provides a control method of a heat pump water heater, which is mainly used for controlling a heat pump water heater provided by the above content of the embodiment of the present invention, that is, the heat pump water heater includes a water tank and a compressor, wherein, the compression The motor coil of the machine has a multi-stage winding, and the resistance of the nth winding of the multi-stage winding is smaller than the resistance of the n-1th winding of the multi-stage winding, and n is a natural number of 2 or more. 9 is a flow chart of a method for controlling a heat pump water heater according to an embodiment of the present invention. As shown in FIG. 9, the control method of the embodiment includes the following steps S11 to S13: Step S11: detecting the water temperature in the water tank, and obtaining the detected water temperature. The temperature of the water in the water tank is detected by a thermocouple or a thermal resistance type temperature sensor to obtain the detected water temperature. The temperature of the water in the water tank can also be detected by the temperature sensing temperature package to obtain the detected water temperature. Step S12: Find the winding corresponding to the detected water temperature, and obtain the p-th winding p is a natural number, l≤p≤n, and store the corresponding relationship between different water temperature intervals and the number of winding stages in the heat pump water heater, wherein one water temperature interval The water temperature in the range corresponds to a winding of the same level. The water temperature in different intervals corresponds to different grades of windings. As shown in Table 1, the windings corresponding to the detected water temperature are mainly used to find the preset where the detected water temperature is located. The temperature range is then taken to obtain the winding corresponding to the preset temperature range found, as the p-th winding. Table 1

Figure imgf000011_0001

The preset temperature preset temperatures T, Tq 2 ... Tq^ in each temperature interval in Table 1 can be preset in the following manner:

(1) detecting the outdoor ambient temperature of the heat pump water heater Te;

(2) The ambient temperature Te is subtracted from 8 to 10 ° C to obtain the difference temperature; (3) calculating the saturation pressure corresponding to the difference temperature to obtain the evaporation pressure Pe;

(4) The optimum switching pressure ratio determined by the compressor γ determines the condensation pressure corresponding to the evaporation pressure Pe Pc, Pc=Pe»Y;

(5) Calculate the saturation temperature corresponding to the condensing pressure Pc to obtain the condensing temperature Tc; (6) Subtract the condensing temperature Tc by 8~10 °C to obtain the switching water temperature Tq';

(7) Compare the switching water temperature Tq' with the temperature interval [Tq min , Tq ] set in advance according to the specific operating conditions of the heat pump water heater (refrigerant type, tank capacity, etc.): If Tq'e [Tq min , Tqmax] , 贝 lj Tq 尸Tq';

Figure imgf000012_0001
If Tq'>T qmax , then Tq^Tq^x;

(8) Subtract T qi from 5 to 10 ° C to obtain Tq 2 ; subtract Tq 2 from 5 to 10 ° C to obtain Tq 3 , and so on, to obtain Tq 4 , Tq 5 ... Tq n _i o Step S13: Control the compressor to operate with the p-th winding, and return to step S11. The motor coil with multi-stage windings is mainly formed by setting different taps on the motor coils and connecting different taps to form different levels. Winding, combined with the specific structure of the motor coil provided by the above content of the embodiment of the invention (the motor coil has a static contact and a plurality of moving contacts, and a first switch is connected between the static contact and each movable contact) To illustrate the control of the compressor, by controlling the first switch between the stationary contact and the movable contact jp of the plurality of movable contacts to control the connection between the stationary contact and the movable contact jp, thereby realizing The control compressor is operated by a p-stage winding, wherein the movable contact j p is a movable contact that can be connected to the stationary contact to form a p-th stage winding. Until the water temperature in the water tank reaches the target temperature, or receives a stop command, the compressor is stopped. When the winding resistance of the compressor is large, the current passing through the compressor is small, the compressor is equivalent to a small motor, and conversely, the current passing through is large, and the compressor is equivalent to a large motor, and the small motor is optimal. The resistance torque corresponding to the working point is small, and the resistance torque corresponding to the optimal working point of the large motor is large. In the work of heat pump water heaters, the higher the water temperature, the higher the resistance torque of the heat pump water heater. If the windings used by the compressor are unchanged, the operating state of the compressor deviates from its optimal operating point at high water temperature, resulting in efficiency. Decrease, by pre-storing the correspondence between the water temperature and the winding, determining the winding size to be used by the compressor according to the detected water temperature, and then controlling the compressor to operate according to the found winding, achieving the control pressure at a relatively low temperature. The compressor is operated with a larger resistance winding to operate the compressor as a small motor, and the compressor is operated at a relatively high temperature with a smaller resistance winding to upgrade the compressor to a larger The motor, in turn, controls the compressor to follow the change of the water temperature and maintains the optimal working point, thereby improving the operating efficiency of the compressor, and solving the problem that the performance of the heat pump water heater decreases with the increase of the water temperature in the prior art, and further The effect of improving the overall performance of the heat pump water heater is achieved. Preferably, each of the multi-stage windings has a capacitor unit connected in parallel with each other, wherein the capacitance of the nth capacitor unit is greater than the capacitance of the n-1th capacitor unit, and the nth capacitor unit is connected in parallel with the nth winding. The capacitor unit, the n-1th capacitor unit is a capacitor unit connected in parallel on the n-1th winding. The composition and implementation of the capacitor unit can be realized by the capacitors in FIG. 7 and FIG. 8 above, and details are not described herein. The control method of the embodiment of the present invention further includes: controlling the compressor to operate using the p-th capacitor unit while controlling the compressor to operate using the p-stage winding, wherein the p-th capacitor unit is parallel to the p-th stage winding Capacitor unit. Since the winding resistance values used in the compressor operation are different, capacitors with different capacitance values are required to match, that is, the size of the motor matches the size of the capacitor, and the larger the motor, the required matching The larger the capacitance, the smaller the opposite. If the motor is switched from a small motor to a large motor, and there is no matching capacitor access circuit, the unit may not operate normally. The performance is as follows: If the unit is in the startup state, it may not start normally. If the unit is in normal operation, In operation, it may cause abnormal conditions such as poor operation and unstable current. In the control method of the preferred embodiment of the present invention, by controlling the compressor to operate simultaneously with the matched windings and the capacitor unit, the capacitor unit can buffer a large current during startup in the electrical control of the heat pump water heater during operation. The function of the stabilizing circuit achieves the effect of improving the operational stability of the heat pump water heater. From the above description, it can be seen that the present invention achieves an effect of improving the overall performance of the heat pump water heater. It should be noted that the steps shown in the flowchart of the accompanying drawings may be performed in a computer system such as a set of computer executable instructions, and, although the logical order is shown in the flowchart, in some cases, The steps shown or described may be performed in an order different than that herein. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

 Claims
A heat pump water heater, comprising:
 Water tank
 a detecting unit, configured to detect a water temperature in the water tank, and obtain a detected water temperature;
 a compressor, the motor coil of the compressor has a plurality of windings, wherein a resistance of the nth winding of the multi-stage winding is smaller than a resistance of the n-1th winding of the multi-stage winding, n a natural number of 2 or more;
 a control unit, connected to the detecting unit and the compressor, for finding a winding corresponding to the detected water temperature, obtaining a p-th winding, and controlling the compressor to adopt the p-th winding Operation, wherein, p is a natural number, l≤p≤n, a correspondence relationship between different water temperature intervals and winding stages is stored in the heat pump water heater, and the average water temperature in the water temperature interval is higher, corresponding The number of winding stages is larger.
2. The heat pump water heater according to claim 1, wherein the motor coil has a static contact and a plurality of movable contacts, and the static contact and the movable contact of the plurality of movable contacts Point n is connected to form the nth stage winding, and the static contact is connected to the moving contact of the plurality of moving contacts to form the n-1th stage winding, wherein a control unit is configured to control the static contact to be connected to one of the plurality of movable contacts, the control unit controls the static contact and the movable contact of the plurality of movable contacts When j P is connected, the compressor operates with the p-th stage winding.
3. The heat pump water heater according to claim 2, wherein the control unit comprises:
 a plurality of first switches, wherein one of the first switches is connected between the static contacts and each of the plurality of movable contacts;
a controller, connected to the detecting unit and the control ends of the plurality of the first switches, for controlling an on-off state of the plurality of the first switches, wherein the controller controls the static contacts The stationary contact is coupled to the movable contact j P when the first switch between the movable contact j P is closed.
4. The heat pump water heater according to claim 3, wherein the heat pump water heater further comprises: a capacitor unit, wherein each of the plurality of windings has one of the capacitor units connected in parallel, and The capacitance value of the n capacitor unit is greater than the capacitance value of the n-1th capacitor unit, the nth capacitor unit The capacitor unit connected in parallel on the nth winding, the n-1th capacitor unit is a capacitor unit connected in parallel on the n-1th winding. The heat pump water heater according to claim 4, wherein the capacitor unit comprises:
 n capacitors, wherein the n capacitors are connected in series; and
 a plurality of second switches, wherein at least n-1 of the n capacitors are connected in parallel with one of the second switches,
 The controller is connected to the control ends of the plurality of the second switches for controlling the switching states of the plurality of the second switches. The heat pump water heater according to claim 4, wherein the capacitor unit comprises:
 n capacitors, wherein any two of the n capacitors are connected in parallel with each other; and a plurality of third switches, wherein at least n-1 of the n capacitors are connected in series with one of the third Switch,
 The controller is connected to the control ends of the plurality of the third switches for controlling the switching states of the plurality of the third switches. A control method of a heat pump water heater, characterized in that the heat pump water heater comprises a water tank and a compressor, wherein a motor coil of the compressor has a multi-stage winding, and a resistance of an n-th winding of the multi-stage winding The value is smaller than the resistance of the n-1th winding of the multi-stage winding, and n is a natural number of 2 or more, and the control method includes:
 Step S11: detecting a water temperature in the water tank to obtain a detected water temperature;
 Step S12: Find a winding corresponding to the detected water temperature to obtain a p-th winding, wherein p is a natural number, l≤p≤n, and a correspondence between different water temperature intervals and winding stages is stored in the heat pump water heater. Relationship, and, the higher the average water temperature in the water temperature interval, the larger the number of the winding stages; and
 Step S13: Controlling the compressor to operate using the p-th stage winding, and returning to step S11. The control method according to claim 7, wherein the finding a winding corresponding to the detected water temperature to obtain the p-th winding comprises:
 Finding a preset temperature range in which the detected water temperature is located;
A winding corresponding to the found preset temperature range is obtained to obtain the p-th stage winding.
The control method according to claim 7, wherein the motor coil has a static contact and a plurality of movable contacts, and controlling the compressor to operate using the p-th winding comprises: controlling The stationary contact is coupled to the movable contact j P of the plurality of movable contacts.
The control method according to claim 9, wherein a first switch is connected between each of the static contact and each of the plurality of movable contacts, and the static touch is controlled Connecting the point to the movable contact jp of the plurality of movable contacts includes: controlling the first switch closing between the stationary contact and the movable contact jp.
The control method according to any one of claims 7 to 10, wherein a capacitor unit is connected in parallel to each of the windings of the multi-stage winding, wherein a capacitance value of the n-th capacitor unit is greater than N-1 capacitance value of the capacitor unit, the nth capacitor unit is a capacitor unit connected in parallel on the nth stage winding, and the n-1th capacitor unit is a capacitor unit connected in parallel on the n-1th stage winding The control method further includes:
 Controlling the compressor to operate using a p-th capacitor unit while controlling the compressor to operate using the p-th stage winding, wherein the p-th capacitor unit is a capacitor connected in parallel on the p-th stage winding unit.
PCT/CN2014/072637 2013-04-28 2014-02-27 Heat pump water heater and control method therefor WO2014176947A1 (en)

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