Method for controlling a circulation pump

Abstract

The present disclosure relates to a method for controlling a circulating pump (7) installed in a system (1) for heating or cooling, where the system (1) is equipped with one or more temperature control valves (9), where the method comprises:-operating the pump at an operating point, where the current operating point is defined as the intersection of an adaptable pump characteristic curve and a variable system characteristic curve (33a-c), where the current operating point is defined as the intersection of the adaptable pump characteristic curve and the variable system characteristic curve (33a-c); the system characteristic curve (33a-c) varies with the common opening (OD) of the one or more temperature control valves (9), in which the pump characteristic curve is adapted by setting the speed of the pump (7), in which the speed of the pump (7) is controlled in such a way that the operating point follows an adjustable control curve; and-automatically adjusting the control curve when the system characteristic curve (33a-c) changes in order to maintain the common opening (OD) of the one or more temperature control valves (9) within a desired range between a minimum common opening (ODmin) and a maximum common opening (ODmax), characterized in that the automatically adjusting control curve comprises determining a system variable (kv) susceptible to a change in the system characteristic curve, and using the system variable (kv) as an input to provide a feed-forward signal (27) to automatically adjust the control curve in the feed-forward control (29).

Description

Technical Field

[0001] The present disclosure relates to a method for controlling a circulation pump installed in a system for heating or cooling, wherein the system is equipped with one or more temperature control valves. For example, the system may be a common domestic heating system with a radiator equipped with a temperature control valve, such as a thermostatic radiator valve (TRV). Alternatively or additionally, the temperature control valve of the system may be a "smart valve" that is remotely temperature controlled by a smart valve application. Background Art

[0002] The circulation pump is usually installed at the piping system as a separate circulation pump assembly, which includes a pump, an electric motor for driving the pump, and an electronic device housing with electronic devices for controlling the speed of the motor. The circulation pump can be operated in different optional control modes (e.g., a constant pressure control mode or a proportional pressure control mode). Each control mode can include a certain number of selectable pump control curves. If the pump operates following a specific pump control curve, the operating point of the pump will be consistent with the pump control curve as much as possible.

[0003] When the piping system includes a thermostatic valve, the valve is gradually closed when the demand for thermal energy decreases, and is gradually opened when the demand for thermal energy increases, in order to achieve the target temperature. Usually, the circulator pump, as a separate pump component, does not have any direct information about the degree to which the valve is open or closed. If the pump follows its set pump control curve, it may run at an unnecessarily high speed when the valve is closed, or at a speed that is too low when the valve is open. A too high speed of the pump wastes energy saving potential and causes undesirable flow noise. A too low speed of the pump has a negative impact on user comfort, because the cooling or heating system does not reach its target temperature, at least not within the desired time.

[0004] It is known in the prior art to automatically adapt a pump control curve in a closed-loop control based on the pipeline resistance value as a feedback value. For example, EP0726396B1 or EP1323986B1 describe such automatic adaptation of a pump control curve in a closed-loop control.

[0005] It has been shown that the known methods of automatic adaptation of the pump control curve successfully reduce the energy consumption and the flow noise when the valve is closed. However, when the valve is open during periods of high thermal energy demand, the known methods of automatic adaptation of the pump control curve also appear to be too slow. The user thus experiences a lack of comfort because the cooling or heating system does not reach its target temperature, at least not within the expected time.

[0006] The object of the present disclosure is therefore to provide a method for controlling a circulation pump which, on the one hand, adapts the pump control curve sufficiently quickly both when the proportional control valves in the system are closed and when they are opened. On the other hand, when the proportional control valves are closed, the energy consumption and the flow noise are still to be reduced as much as possible. Summary of the invention

[0007] According to a first aspect of the present disclosure, there is provided a method for controlling a circulation pump installed in a system for heating or cooling, wherein the system is equipped with one or more temperature control valves. The method comprises:

[0008] - operating the pump at an operating point, wherein the current operating point is defined as the intersection of an adaptable pump characteristic curve and a variable system characteristic curve, wherein the system characteristic curve varies as a function of the common opening of one or more thermostatic valves, wherein the pump characteristic curve is adapted by setting a speed of the pump, wherein the speed of the pump is controlled in such a way that the operating point follows the adjustable pump control curve; and

[0009] - automatically adjust the pump control curve when the system characteristic curve changes to keep the common opening of one or more thermostatic valves within a desired range between a minimum common opening and a maximum common opening,

[0010] It is characterized in that

[0011] Automatically adjusting the pump control curve includes determining a system variable susceptible to changes in the system characteristic curve, and using the system variable as an input to provide a feed-forward signal to automatically adjust the pump control curve in a feed-forward control.

[0012] The term "common opening" of one or more thermostatic valves (i.e. thermostatic valves in the form of proportional control valves) is to be understood as an absolute or relative measure of the degree of opening or closing of all these thermostatic valves through which the circulating pump pumps the heated or cooled liquid, for example ranging from 0% to 100%. If there is only one valve in the system, the "common opening" can simply be the opening of the valve. If there are two or more valves in the system, the weighted or unweighted average of the openings of the valves can be considered as the "common opening". The independent pump component has no information about the common opening, but it "feels" a pipeline resistance that is proportional to the common opening of the valves. The pump experiences the lowest pipeline resistance when all valves of the system are open to the maximum extent. The pump experiences the highest pipeline resistance when all valves except one are closed and the open valve is almost closed. It can be assumed that the pipeline resistance is constant as long as the common opening of the valves does not change.

[0013] The system characteristic curve varies with the pipe resistance, i.e. it varies with the common opening of the valve. If the system characteristic curve changes, the pump characteristic curve is adapted by changing the pump speed to keep the operating point on the pump control curve. If the pump control curve (e.g. a proportional pressure control curve in the form of a linear line in a head-flow-diagram) is fixed, the following undesirable situations occur: the pump does not run at full speed when the valve is fully open due to high thermal energy demand, and the pump runs too fast when the valve is close to closing or fully closed due to low thermal energy demand or no thermal energy demand. In other words, it is most desirable to keep the common opening of the valve within the desired range between the minimum common opening and the maximum common opening. Within this desired range, the thermostatic valve can react to the rise and fall of the thermal energy demand. Therefore, the pump control curve is not fixed, but adjustable to keep the common opening of the valve within the desired range as much as possible.

[0014] The inventive concept now consists in accelerating the adjustment of the pump control curve by determining system variables susceptible to changes in the system characteristic curve and using the system variables as input to provide a feedforward signal to automatically adjust the pump control curve in a feedforward control.

[0015] For example, a system variable may be a flow factor, also expressed as a kv value. The kv value is defined, for example, in the following document: "Fluidic characteristic quantities of control valves and their determination", VDI, VDE, September 2007, 2173, retrieved on April 17, 2020. The kv value represents the amount of fluid in m that passes through the system at a given common opening. 3 / h water flow, where the pressure drop across the valve is 1 bar. It should be noted that the full definition indicates that the flow medium must have a pressure of 1000 kg / m 3 The specific gravity and 10 -6 m 2 / s kinematic viscosity, such as water. The kv value is generally defined as Where q is m 3 is the flow rate in / h, Dp is the pressure drop across the valve in bar, and SG is the specific gravity of the flowing medium (for water, SG=1).

[0016] The pump can determine or estimate system variables based on its current operating point and performance indicators such as the head and / or flow it provides, its current pumping speed, power consumption, and / or the current currently drawn by the pump drive motor. The determined or estimated system variables are then used as inputs to provide feedforward signals to automatically adjust the pump control curve in feedforward control.

[0017] Optionally, the method may further include: continuously or periodically monitoring a head value h indicating the head currently provided by the circulation pump and a flow value q indicating the flow currently provided by the circulation pump, wherein the head value h and the flow value q are used to determine system variables, such as a kv value. In order to avoid the need for a pressure sensor and / or a flow sensor, it is beneficial to derive the head value and the flow value from electrical performance indicators of the pump motor (e.g., motor speed and power consumption).

[0018] Optionally, the step of automatically adjusting the pump control curve may further include:

[0019] - record the maximum and minimum values ​​of system variables that have been determined over a past period of time; and

[0020] - Determining a common opening value indicative of a common opening of one or more thermostatic valves as a function of the distance of the system variable from a recorded maximum value and / or a recorded minimum value.

[0021] The maximum kv value and the minimum kv value may be used to estimate the kv value for the highest common opening of the valves and the lowest common opening of the valves, respectively, over time.

[0022] Optionally, automatically adjusting the pump control curve may also include using a stored adaptable mapping between the system variable and the feedforward signal to be applied to the feedforward control. This is useful to take into account deviations from the target opening indicated by the PI controller. The mapping used for the feedforward may be adapted to keep the deviation from the target opening to a minimum.

[0023] Optionally, in addition to the system variables, the deviation of the determined common opening value from a predetermined reference common opening can be used as a further input to provide a feedforward signal, and wherein said deviation is used to update the stored adaptable map. It should be noted that under normal operation, this further input is much smaller than the contribution of the system variables to the feedforward control. The contribution of the deviation of the opening from the target opening is a rather small correction to the feedforward control, for example in the range of + / -5%.

[0024] Alternatively, the stored adaptable mapping may include a list of relative values ​​defining which control curve to apply at a predetermined system variable point within a total range of applicable control curves, wherein the relative values ​​are interpolated between the predetermined system variable points. For example, the applicable pump control curve may be within a range between a lowest proportional pressure curve PP1 and a highest proportional pressure curve PP3. The stored adaptable mapping may include a list of relative values ​​expressed in terms of percentages ranging from 0% for the lowest proportional pressure curve PP1 to 100% for the highest proportional pressure curve PP3.

[0025] Optionally, if the updated mapping has non-negative gradients throughout, the stored adaptable mapping may be updated for only one or two relative values ​​at those predetermined system variable points closest to the currently determined system variable, and wherein if the updated mapping does not have non-negative gradients throughout,

[0026] - in addition to updating the stored adaptable mapping for one or two relative values ​​at those predetermined system variable points closest to the currently determined system variable, updating the stored adaptable mapping for relative values ​​at all higher predetermined system variable points by shifting those relative values ​​upward by an amount required to avoid the updated mapping having a negative gradient, and / or

[0027] In addition to updating the stored adaptable mapping for one or two relative values ​​at those predetermined system variable points that are closest to the currently determined system variable, the stored adaptable mapping is also updated for the relative values ​​at all lower predetermined system variable points by shifting those relative values ​​downward by an amount required to avoid the updated mapping having a negative gradient.

[0028] The mapping between the system variable and the feedforward signal to be applied for feedforward control must not have a negative gradient, because when the valve is open, i.e. the kv value rises, the pump must not decrease the pump control curve. Similarly, when the valve is closed, the pump control curve must not increase.

[0029] Alternatively, the adjustable pump control curve may be a proportional pressure curve. This is particularly beneficial if the valve is installed at a heating radiator.

[0030] Optionally, the system may comprise one or more thermal energy consumers, and the one or more temperature-controlled valves may be automatically actuated valves and / or thermostatically actuated valves installed at said thermal energy consumers.Preferably, the thermal energy consumers are radiators of the heating system.

[0031] Optionally, if the determined system variable is less than a previously determined system variable, the feedforward signal may be low pass filtered by a predetermined time constant before it is used to automatically adjust the pump control curve in the feedforward control. This is particularly beneficial for avoiding undesirable rapid oscillations between control curves. Such oscillations have been shown to occur in homes with low kv value variations, where small changes in valve opening may result in larger changes in the pump head that the valve is trying to compensate for. Preferably, to avoid such oscillations, a first order filter with a time constant of, for example, 1200 seconds may be applied if the kv value is falling. However, rising kv values ​​may be used unfiltered as input to the feedforward control.

[0032] Optionally, the pump control curve can be infinitely adjustable within the total range of the applicable pump characteristic curve.

[0033] Optionally, the method may further comprise operating the pump in a first boost mode and / or a second boost mode, wherein:

[0034] As long as the determined common opening value indicative of the common opening of the one or more thermostatic valves is within a predetermined low lift region adjacent to a minimum common opening or within a predetermined high lift region adjacent to a maximum common opening, a gain factor is applied in the first lift mode to more strongly adjust the pump control curve, and wherein,

[0035] The pump operates at maximum speed in the second boost mode if the following conditions are met:

[0036] - the system variable is within a predetermined speed-up region adjacent to a recorded maximum value of the system variable,

[0037] - The maximum pump control curve is currently applied and the predetermined period of maximum boost time has not yet elapsed.

[0038] The first boost mode can be referred to as PI controller boost. When the kv value and / or the opening is close to the maximum or minimum value, i.e. in the boost region, the first boost mode is preferably applied as the first stage boost. If the first boost mode cannot successfully get the system out of the high boost region within a given period of time, the second boost mode is activated to run the pump at maximum speed for a specific maximum boost time.

[0039] According to another aspect of the present disclosure, there is provided a computer program having instructions, which, when executed by a computer, cause the computer to perform the previously described method.

[0040] According to another aspect of the present disclosure, a circulation pump for installation in a system for heating or cooling is provided, wherein the circulation pump comprises control electronics configured to execute the previously described method or to perform the above-described procedure.

[0041] Optionally, the circulation pump can be automatically programmed at the manufacturing site of the circulation pump to perform the previously described method or perform the previously described procedure. Thus, the fully assembled circulation pump can leave the manufacturing site in a fully programmed state to be shipped to the customer, so that the customer does not need to program the circulation pump.

[0042] The method disclosed herein can be implemented in the form of compiled or uncompiled software code, which is stored on a computer-readable medium with instructions for executing the method. Preferably, the software is installed on the control electronics in the circulating pump according to the present invention. Alternatively or additionally, the method can be performed by software in a cloud-based system and / or a building management system (BMS). BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Embodiments of the present disclosure will now be described by way of example with reference to the following drawings, in which:

[0044] Figure 1 An example of a system for heating or cooling as described herein is schematically shown;

[0045] Figure 2 An example of a circulation pump described herein is shown;

[0046] Figure 3 Schematically illustrates an example of how to automatically adjust a pump control curve according to the present disclosure;

[0047] Figure 4 An example of how to determine a common opening degree according to the present disclosure is schematically shown;

[0048] Figure 5 shows a determined kv value for recording the time of the maximum kv value and the minimum kv value according to the present disclosure;

[0049] Figure 6 schematically illustrates an example of how to control the valve position according to the present disclosure;

[0050] Figure 7 shows a head-flow diagram with indicated lift area for valve position control according to the present disclosure;

[0051] Figure 8a An example of an initial mapping between a kv value and a feedforward signal according to the present disclosure is shown;

[0052] Figure 8b An example of a control curve in a head-flow diagram after the control curve has been adapted to the heating system is shown;

[0053] Fig. 9 schematically illustrates an example of how to update the mapping between the kv value and the feedforward signal according to the present disclosure; and

[0054] Fig.10 Examples of mappings before updating, after updating, and with restrictions to avoid negative gradients are shown. DETAILED DESCRIPTION

[0055] Figure 1A system 1 for heating or cooling, which is usually installed in a home, is shown. For simplicity, the system 1 is referred to as a heating system hereinafter, but it can also be a cooling system without departing from the spirit of the present disclosure. The system 1 includes a thermal energy source 3, such as a gas boiler, a heat exchanger, a heating coil or a heat storage device. The thermal energy source 3 is connected to a pipe system 4 filled with a fluid (such as water), which is used to transfer thermal energy to one or more thermal energy consumers 5, such as a radiator, floor heating or a heat exchanger. At least one circulation pump 7 is installed in the system 1 to circulate the fluid, thereby transferring thermal energy from the thermal energy source 3 to one or more heat consumers 5.

[0056] The system 1 is also equipped with one or more temperature control valves 9, such as thermostatic radiator valves (TRVs), smart valves or other kinds of temperature control valves. Each temperature control valve 9 can be installed near one of the heat consumers 5 to control the fluid flow through the respective heat energy consumer 5. The heat energy consumers 5 are installed in parallel in the system 1, so that each of the heat energy consumers 5 has a fluid inlet connected to a feed line of the system 1 and a fluid outlet connected to a return line of the system 1. Preferably, the associated temperature control valve 9 is installed at the fluid inlet of the heat energy consumer 5.

[0057] Typically, there is no direct control connection between the circulation pump 7 and the thermostatic valve 9. The thermostatic valve 9 is controlled by a closed-loop control using a thermostat, wherein a temperature sensor is used to determine the current temperature and a target temperature can be set for the thermostat. For example, in the case of a heating system, when the measured temperature is below the target temperature, the valve 9 opens in order to increase the flow of the heating fluid through the corresponding thermal energy consumer 5. Similarly, when the measured temperature is above the target temperature, the valve 9 closes in order to reduce the flow of the heating fluid through the thermal energy consumer 5.

[0058] In principle, it is known that it is useful to adjust the speed of the circulation pump 7 according to the common opening of the thermostatic valve 9. Since the circulation pump 7 is an independent device and does not directly know the opening of the thermostatic valve 9, in principle, when the common opening of the valve 9 is low, the circulation pump 7 runs too fast, or when the common opening of the valve 9 is high, the circulation pump 7 runs too slow. This will lead to an undesirable situation in which the circulation pump 7 consumes unnecessary power and generates unnecessary flow noise when the valve 9 is close to closing. In addition, when the valve 9 is opened to the maximum extent during times of high thermal energy demand, the circulation pump 7 may not be able to provide sufficient flow. Therefore, there may be a lack of comfort during times of high thermal energy demand because it takes too long to reach the target temperature. It has been shown that the known "automatic adaptation" algorithm cannot react quickly enough to provide the required thermal energy flow in the case of high thermal energy demand.

[0059] Figure 2 Shown is the installation Figure 1The circulation pump 7 in the heating or cooling system 1 shown. Figure 2 The hardware of the circulation pump 7 shown may be the same as the circulation pumps known in the prior art. However, the difference lies in the way it is programmed and thus controlled to operate. The circulation pump 7 comprises a pump housing 11 having a suction inlet 13 and a pressure outlet 14. The suction inlet 13 and the pressure outlet 14 comprise coaxially aligned flanges pointing in opposite directions, so as to be mounted on a pump such as a pump housing 11. Figure 1 1 . The circulation pump 7 is a wet-running circulation pump having an integrated permanent magnet synchronous motor (PMSM) in a motor housing 15.

[0060] Furthermore, the circulation pump 7 comprises control electronics (not visible) within the motor housing 15 in order to control the speed of the circulation pump 7. The cover 17 of the motor housing 15 comprises a front face 19 with human-machine interface elements such as a display, LED indicators, one or more buttons or switches. The user can manually set the circulation pump 7 to follow a fixed control curve or operate in an "auto-adaptive" control mode to automatically adapt to the applied control curve. For example, in the case of a heating system 1 having a radiator as heat energy consumer 5, the circulation pump 7 can be set to one of three fixed proportional pressure curves PP1, PP2 and PP3. For example, Figure 8b Examples of three fixed control curves are shown as linear lines in a head (h)-flow (q) diagram.

[0061] The circulation pump 7 may also include a wireless interface or connector, through which the control electronics in the circulation pump 7 may be programmed, reprogrammed or updated. Thus, the circulation pump 7 may be programmed during manufacture and assembly and / or when it has been installed in the cooling or heating system 1.

[0062] Figure 3 Shows how to Figure 2The circulation pump 7 is programmed for control. As already mentioned above, it is known in the prior art (for example, from EP0726396B1 or EP1323986B1) to automatically adapt the pump control curve in a closed-loop control based on the pipe resistance value as a feedback value. Therefore, it is known that the circulation pump 7 reacts to changes in the opening of the valve 9 and sets the pump control curve accordingly. Since this has been shown to be too slow to provide sufficient comfort in the case of high thermal energy demand, the idea of ​​the present invention is to use system variables (for example, pipe resistance or kv value) as input to provide a feedforward signal to automatically adjust the control curve in the feedforward control. In other words, the circulation pump 7 is more actively used to indirectly control the valve position. It should be noted that there is no direct control communication between the circulation pump 7 and the valve 9. However, the circulation pump 7 knows that the valve 9 is open when the valve 9 does not obtain enough thermal energy flow, and the valve 9 is closed when the valve 9 obtains too much thermal energy flow.

[0063] therefore, Figure 3 The control schematic diagram shown in FIG. 2 includes valve position control 21 and opening estimation 23. The goal of valve position control 21 is to automatically adjust the control curve when the pipeline resistance changes so as to keep the common opening OD of valve 9 at the minimum common opening OD. min With the maximum common opening OD max Here, the common opening OD is kept as close as possible to a predetermined fixed reference or target opening OD. ref , such as OD ref =0.55, where OD min =0, and OD max = 1. The center range of common opening is desirable because it leaves upward and downward control room to adjust the valve position to the current thermal energy demand.

[0064] The valve position control 21 uses two variables, namely, the current system variable in the form of a kv value and an estimate of the current common opening OD. ) as input. The opening estimation 23 provides the kv value and the estimated common opening value Both are used as outputs to provide these values ​​as inputs to the valve position control 21. The opening estimation 23 converts the head value and flow value As input, the circulation pump 7 continuously or periodically monitors a head value indicating the head h currently provided by the circulation pump 7 In the same manner, the circulation pump 7 continuously or periodically monitors a flow value indicating the flow q currently provided by the circulation pump 7. However, it should be noted that neither the head h nor the flow q is necessarily measured by a pressure sensor and / or a flow sensor. Instead, electronic device performance variables of the circulation pump 7 (e.g., current motor speed, current consumed electrical power or drawn electric motor current) can be used to estimate the current head value. and current flow value Reference Figure 4 and Figure 5 The opening estimation is explained in more detail in 23. Figure 6 The details of the valve position control 21 are explained in more detail. The output of the valve position control 21 is a reference value h indicating which proportional pressure curve the circulation pump 7 is to apply. ref Reference value h ref is the sum of the output from the PI controller 25 and the adaptive feedforward signal 27 .

[0065] Figure 4 The opening estimation 23 is shown in more detail. The opening estimation 23 starts with the head value based on the monitoring and monitored flow values Calculate the kv value. The kv value (also denoted as flow factor) is used as a system variable to express the water flow in cubic meters per hour through the system 1 at a given common opening OD of the valve 9, with a pressure drop of 1 bar across the valve 9. Therefore, the kv value is calculated as The kv value is also limited to be above a predetermined minimum value, such as 3.5m 3 / h. If the head value If the value is below the lower limit, for example 0.5 mH2O, the kv value can be set to kv = OD ref (kv high -kv low )+kv low . Figure 5 Describes how to apply the filter to the calculated kv value in order to determine the current maximum kv value kv high And the current minimum kv value kv low A timer is implemented to ensure that the system 1 is stable since the start of the control algorithm. Estimated opening value It is only evaluated if a predetermined minimum duration (e.g. 10 minutes) has elapsed since the control algorithm was started.

[0066] If the start delay has passed, it is checked whether the kv value exhibits a spike, for example after start after a night set back. As long as the kv value shows a high gradient indicating a kv spike, the opening estimate is suppressed 23. If there is no kv spike, the calculated kv value is filtered to determine the minimum kv value kv representing the lowest kv value and the highest kv value within the specific time. low And the maximum kv value kv highUse a peak detection filter with a forgetting factor to calculate the minimum kv value kv low And the maximum kv value kv high This is achieved by low-pass filtering the kv values, where the time constant used for filtering is based on kv (kv low and kv high ) changes. high , the time constant of the change gives a signal that changes quickly toward higher values ​​and slowly toward lower values. low , the time constant of the change gives a signal that changes quickly toward lower values ​​and slowly toward higher values. Figure 5 The opening is estimated according to the following formula

[0067] k υ，Δ =max(k υhigh -k υlow , k υBandMin )

[0068]

[0069] It should be noted that k vBandMin Used to protect the algorithm from division by zero and can be set to, for example, 0.03. v，dynband，min can be used to stop re-estimation, i.e., k v，dynband，min Can be set to 0.05. In the case of very small changes in kv value, the estimated opening value is set to the reference value OD ref This is done to ensure that the value kv low and kv high has been initialized, and there is sufficient signal-to-noise ratio in the KV signal to perform meaningful control.

[0070] Figure 6 The valve position control 21 is shown in more detail. When the valve position control 21 is activated, it receives the calculated kv value and the estimated opening value As an input variable, the kv value is used to calculate the output Out of the adaptive feedforward control 29 ff As the feedforward signal 27. The adaptive feedforward control 29 includes using the kv value and the feedforward signal 27Out ff An adaptable mapping of storage between . Figure 8a An example of such an adaptable map is shown, which is initially stored in the control electronics of the circulation pump 7. The feedforward signal 27Out ff can be computed as a linear interpolation between the stored mapping points, such as

[0071]

[0072] Among them, ff kv，0 is the point just below the current kv value, and ff href，0 is the corresponding relative proportional pressure curve. kv，1 is the point just above the current kv value, and ff href，1 is the corresponding relative proportional pressure curve. If the kv value is outside the mapped range, the relative proportional pressure curve values ​​of the first and last points in the mapping are used.

[0073] The PI controller 25 refers to the common opening OD ref Common opening with estimate The difference between is taken as the input error to be minimized. The PI controller 25 may include controller parameters such as gain, time constant and controller limit parameters that may be predetermined for normal operation. However, when the system 1 is in a state such as Figure 7 In the boost region shown, the controller parameters may be set to specific values. In particular, in the case where the system 1 is in the boost region, when the boost control is activated in the PI controller 25, the controller gain and the controller limit parameters may be multiplied by a certain factor. Boosting the PI controller 25 by applying the gain factor is a first boost mode according to an embodiment of the present disclosure. In the case where the thermal energy demand is particularly high, the circulation pump may be operated in a second boost mode, in which the kv value is within the range of kv. max If the maximum pump control curve is applied and the predetermined period of maximum boost time has not elapsed, the circulation pump 7 is set to maximum speed.

[0074] The output 28Out of the PI controller 25 PI (i.e., the estimated common opening Common opening OD with the predetermined reference ref The deviation of the valve position control 21 is used to update the stored adaptive map of the feedforward control 29. In addition, the output h of the valve position control 21 is ref is the feedforward signal 27Out ff and the output 28Out of the PI controller 25 PI However, it should be noted that the output 28Out of the PI controller 25 PI The output h to the valve position control 21 in normal operation (ie outside any lifting mode) is ref Provides a feedforward signal of 27Out ff A much smaller contribution, e.g. + / -5%, of the feedforward signal 27Out ff The range is from 0% to 100% and is based on the kv value used as input to the feedforward control 29.

[0075] Figure 7 A head (h)-flow (q) diagram is shown with a pump characteristic curve 31 for maximum pump speed and three displayed system characteristic curves 33a-c. The system characteristic curve 33a represents the system characteristic curve when the valve 9 has a minimum opening (OD=0) and the kv value is at its minimum value kv min The system characteristic curve 33b shows that the common opening OD of the valve 9 is at the reference value OD ref (For example, OD ref =0.55). The goal of the valve position control 21 is to make the common opening of the valve 9 at the reference value OD ref Or at the reference value OD ref The circulation pump 7 is operated in a manner close to the system characteristic curve 33c. The system characteristic curve 33c indicates that the common opening OD is at the maximum value (OD=1) and the kv value is at its maximum value kv max The boost region of the first boost mode to which the PI controller 25 is applied is a band close to the limit system characteristic curves 33a and 33c.

[0076] Figure 8a shows zero and 2.5m 3 The kv value between / h and the initial mapping 26 of the relative proportional pressure curve to be applied expressed as a percentage. A relative proportional pressure curve value of 100% can represent the highest proportional pressure curve PP3. A relative proportional pressure curve value of 0% can represent the lowest proportional pressure curve PP1. The feedforward signal Out as the output 27 of the feedforward control 29 ff yes Figure 8a Then, we will interpolate between the mapping points in Figure 8a The mapping is stored in the control electronics of the circulating pump 7 .

[0077] Figure 8b An example of a control curve in a head (h)-flow (q) diagram is shown after it has been adapted to the heating system 1. 3 / h or 0.1m 3 / h flow rate follows the minimum proportional pressure curve PP1. 3 / h and 0.2m 3 / h, the proportional pressure curve gradually increases to target the flow rate at 0.2m 3 / h and 0.9m 3 For flow rates between 0.9 m / h and 1.5 m / h, the proportional pressure curve PP3 is used. 3 / h, the circulating pump 7 reaches its maximum value in the example shown and for temperatures above 0.9 m 3 The flow rate value of / h follows its maximum pump characteristic curve 31. When the pump reaches its maximum speed limit, the head increases with the flow rate to above 0.9m 3 / h and decreases.

[0078] Fig. 9 shows how to use the output 28Out of the PI controller 25 PI To make the feedforward control 29 used Figure 8a The output 28Out of the PI controller 25 is adapted. PI Used to determine the feedforward signal 27Out ff If the current feedforward signal 27Out ff For the current heat demand, the output 28Out of the PI controller 25 is perfect. PI If the output of the PI controller 25 is positive, the feedforward signal 27Out needs to be increased. ff Similarly, the negative output 28Out of the PI controller 25 PI Indicates to reduce the feedforward signal 27Out ff The stored mapping is adapted by changing the mapping point closest to the current kv value. Over time, the mapping adapts to give the appropriate relative proportional pressure curve value h required for a particular kv value. ref .

[0079] Only when the change in kv value is above the noise level (i.e., k v，Δ ≥k v，dynband，min ) and no kv peak is currently detected, the adaptation of the feedforward control 29 is performed. The output 28Out of the PI controller 25 is adjusted based on the PI controller limiting parameters PI The limitation of prevents an overly aggressive adaptation when the PI controller 25 operates in the first boost mode. The non-zero output 28Out of the PI controller 25 PI Indicates the deviation of the current kv value from the interpolation map and triggers the output 28Out of the PI controller 25 PI Correction of the two closest mapping points in proportion so that the interpolation between these two corrected mapping points is based on the current kv value. If the current kv value is outside the mapping range of kv values, only the lowest or highest mapping point is adapted accordingly. The adapted mapping points are limited to relative proportional pressure curve values ​​between 0% and 100%.

[0080] To avoid negative gradients in the mapping, mapping points at all kv values ​​above the adapted higher nearest mapping point are shifted upward by the minimum amount required to avoid the updated mapping having negative gradients. Similarly, in the case of adapting the lower nearest mapping point downward, all mapping points with kv values ​​below the downwardly adapted lower nearest mapping point are shifted downward by the amount required to avoid the updated mapping having negative gradients. Finally, the updated mapping is stored for subsequent iterations of the feedforward control 29.

[0081] Fig.10 Shown are examples of how a mapping may look before updating (on the left), after updating (in the middle), and after adapting the mapping to avoid negative gradients (on the right). Fig.10 The stored mapping before the update is shown on the left. However, the positive output 28Out of the PI controller P Indicates that the mapping near the current kv value should be increased. Therefore, the adjacent mapping points are shifted upward accordingly. The shift is weighted according to the distance of the current kv value to the mapping point. In the case shown, the closest higher neighboring mapping point is shifted upward more than the closest lower neighboring mapping point. Since this will result in a negative gradient in the mapping between the closest higher neighboring mapping point and the next closest higher mapping point, all mapping points with a kv value higher than the closest higher neighboring mapping point are shifted upward by the minimum amount A required to avoid the negative gradient.

[0082] In the foregoing description, where reference is made to integers or elements that have known, obvious or foreseeable equivalents, then these equivalents are incorporated herein as if individually set forth. Reference should be made to the claims for determining the true scope of the disclosure, which should be interpreted to encompass any such equivalents. The reader will also understand that integers or features of the disclosure that are described as optional, preferred, advantageous, convenient, etc. are optional and do not limit the scope of the independent claims.

[0083] The above embodiments are to be understood as illustrative examples of the present disclosure. It should be understood that any feature described with respect to any one embodiment may be used alone or in combination with other features described, and may also be used in combination with one or more features of any other embodiment, or in combination with any combination of any other embodiment. Although at least one exemplary embodiment has been shown and described, it should be understood that other modifications, substitutions, and alternatives are obvious to those of ordinary skill in the art and may be changed without departing from the scope of the subject matter described herein, and this application is intended to cover any adaptation or variation of the specific embodiments discussed herein.

[0084] In addition, "comprising" does not exclude other elements or steps, and "one" or "an" does not exclude the plural. In addition, the characteristics or steps described with reference to one of the above exemplary embodiments may also be used in combination with other characteristics or steps of the other exemplary embodiments described above. The method steps may be applied in any order or in parallel, or may constitute a part or a more detailed version of another method step. It should be understood that all such modifications should be embodied within the scope of the patent authorized herein, because these modifications reasonably and appropriately fall within the scope of the contribution to the art. Such modifications, substitutions and replacements can be made without departing from the spirit and scope of the present disclosure, and the spirit and scope of the present disclosure should be determined by the appended claims and their legal equivalents.

[0085] List of reference numerals:

[0086] 1 Cooling or heating system

[0087] 3 Thermal energy

[0088] 4 Pipeline system

[0089] 5 Heat energy consumers

[0090] 7 Circulation pump

[0091] 9 Temperature control valve

[0092] 11 Pump housing

[0093] 13 Suction inlet

[0094] 14 Pressure outlet

[0095] 15 Motor housing

[0096] 17 Motor housing cover

[0097] 19 Front of motor housing cover

[0098] R Rotor axis

[0099] 21 Valve position control

[0100] 23 Opening estimation

[0101] 25 PI controller

[0102] 27 Feedforward control output Out ff

[0103] 28 PI controller output Out PI

[0104] 29 Adaptive Feedforward Control

[0105] 31 Pump characteristic curve at maximum speed

[0106] 33a-c System characteristic curve

[0107] PP1 Proportional Pressure Curve

[0108] PP2 Proportional Pressure Curve

[0109] PP3 Proportional Pressure Curve

[0110] A is the amount of shift required to avoid negative gradients

Claims

1. A method for controlling a circulation pump (7) installed in a system (1) for heating or cooling, wherein: The system (1) is equipped with one or more temperature control valves (9), wherein the method comprises: - operating the pump at an operating point, wherein the current operating point is defined as the intersection of an adaptable pump characteristic curve and a variable system characteristic curve (33a-c), wherein the system characteristic curve (33a-c) varies as a function of the common opening degree (OD) of the one or more thermostatic valves (9), wherein the pump characteristic curve is adapted by setting the speed of the pump (7), wherein the speed of the pump (7) is controlled in such a way that the operating point follows the adjustable control curve; and - automatically adjusting the control curve when the system characteristic curve (33a-c) changes to keep the common opening (OD) of the one or more temperature control valves (9) at a minimum common opening (OD) min ) and the maximum common opening (O Dmax ) is within the expected range, Features Automatically adjusting the control curve includes determining a system variable (kv) susceptible to changes in the system characteristic curve, and using the system variable (kv) as an input to provide a feedforward signal (27) to automatically adjust the control curve in a feedforward control (29).

2. The method according to claim 1, further comprising: Continuously or periodically monitoring a head value indicating the head (h) currently provided by the circulation pump (7) and a flow value indicating the flow rate (q) currently provided by the circulation pump (7) Among them, the lift value and the flow value Used to determine the system variable (kv).

3. The method according to claim 1 or 2, wherein: Automatically adjusting the control curve further includes: - Record the maximum value (kv) of the system variable (kv) that has been determined in the past period of time high ) and minimum value (kv low );as well as -According to the system variable (kv) and the maximum value recorded (kv high ) and / or the minimum value recorded (kv low ), determining a common opening value indicating a common opening (OD) of the one or more temperature control valves (9) 4. A method according to any one of the preceding claims, wherein: Automatically adjusting the control curve further comprises using a stored adaptable mapping between the system variable (kv) and the feedforward signal (27) to be applied to the feedforward control (29).

5. The method according to claim 4, wherein: The common opening value determined Common opening with predetermined reference (OD ref ) is used as a further input to provide the feedforward signal (27), and wherein the deviation is used to update the stored adaptable mapping.

6. The method according to claim 4 or 5, wherein: The stored adaptable mapping includes a list of relative values ​​that define which control curve to apply at predetermined system variable points within a total range of applicable control curves, wherein the relative values ​​are interpolated between the predetermined system variable points.

7. The method according to claim 6, wherein: If the updated mapping has a non-negative gradient throughout, then updating the stored adaptable mapping only for one or two relative values ​​at the predetermined system variable point closest to the currently determined system (1) variable (kv), and wherein, if the updated mapping does not have a non-negative gradient throughout, then - in addition to updating the stored adaptable map for one or two relative values ​​at predetermined system variable points closest to the currently determined system (1) variable (kv), updating the stored adaptable map for relative values ​​at all higher predetermined system variable points by shifting the relative values ​​upward by an amount required to avoid that the updated map has a negative gradient, and / or - In addition to updating the stored adaptable map for one or two relative values ​​at predetermined system variable points closest to the currently determined system (1) variable (kv), the stored adaptable map is also updated for relative values ​​at all lower predetermined system variable points by shifting the relative values ​​downward by an amount required to avoid that the updated map has a negative gradient.

8. A method according to any one of the preceding claims, wherein: The adjustable control curves are proportional pressure curves (PP1, PP2, PP3).

9. A method according to any one of the preceding claims, wherein: The system (1) comprises one or more thermal energy consumers (5), and the one or more temperature-controlled valves (9) are automatically actuated valves and / or thermostatically actuated valves installed at the thermal energy consumers (5).

10. A method according to any one of the preceding claims, wherein the feedforward signal (27) is low-pass filtered with a predetermined time constant before being used for automatically adjusting the control curve in the feedforward control (29) if the determined system variable (kv) is less than a previously determined system variable (kv).

11. A method according to any one of the preceding claims, wherein: The control curve is infinitely adjustable within the entire range of the applicable pump characteristic curve.

12. The method according to any one of the preceding claims, further comprising: The pump is operated in a first lifting mode and / or a second lifting mode, wherein: As long as the common opening value (OD) of the one or more temperature control valves (9) is determined, At the minimum common opening (OD min ) or in a predetermined low lift area adjacent to the maximum common opening (O Dmax ), applying a gain factor in the first boost mode to more strongly adjust the control curve in a predetermined high boost region adjacent to , and Wherein, the pump operates at maximum speed in the second lifting mode if the following conditions are met: - the system variable (kv) is at the maximum value (kv) recorded with the system variable (kv) high ) is within a predetermined speed increase area adjacent to - the maximum control curve currently applied, and -The scheduled period of maximum boost time has not yet elapsed.

13. A computer program comprising instructions which, when executed by a computer, cause the computer to perform a method according to any one of the preceding claims.

14. A circulation pump (7) for installation in a system (1) for heating or cooling, wherein: The circulation pump (7) comprises control electronics configured to carry out a method according to any one of claims 1 to 12 or to carry out a program according to claim 13.

15. The circulation pump (7) according to claim 14, wherein: The circulation pump (7) is automatically programmed at the manufacturing site of the circulation pump (7) to carry out the method according to any one of claims 1 to 12 or to carry out the program according to claim 13.

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