Power Conversion Module Cooling Control System

Abstract

A load-linked automatic cooling path switching control system according to the present invention comprises: a multi-sensor unit (110) for measuring a plurality of state information including a load rate (P) of a power conversion module, a dielectric temperature (T_d), and a case temperature (T_c); a data processing unit (120) for collecting the plurality of state information and generating input data for control by removing noise, normalizing, or filtering; a control algorithm unit (130) for performing state transitions between cooling modes based on the input data for control and a set of state variables including (i) a current state, (ii) a previous state, and (iii) a state maintenance time, and determining a target flow rate according to a finite state machine structure including a natural convection cooling mode and a water cooling mode; and a cooling water flow rate control unit (140) for controlling a pump rotation speed, a valve opening rate, or a corresponding cooling water flow rate according to the target flow rate.

Description

Technology Field

[0001] The present invention relates to a cooling control system for a power conversion module, and more specifically, to a load-linked automatic cooling path switching control system that selectively switches between a natural convection cooling path and a forced water cooling path based on load rate, temperature, and state history data. Background Technology

[0003] As power converters become more high-output and highly integrated, heat density is rapidly increasing, making stable thermal management technology essential. Conventional technologies have generally utilized fan-based air cooling or water-circulating cooling methods, and most systems adopt a fixed cooling structure that maintains a constant cooling capacity.

[0004] However, this fixed cooling method has the problem of consuming excessive cooling energy even during low-load periods, and it degrades overall system efficiency, particularly in data center and high-efficiency power device environments. Furthermore, existing technologies fail to actively respond to cooling requirements, even though they vary significantly over time in environments with frequent load fluctuations.

[0005] Although dielectric immersion-based cooling structures have recently been proposed, control technologies for switching between natural convection and forced water cooling depending on the situation have not been specifically presented. In particular, cooling path switching technology integrating multi-sensor-based state determination, hysteresis application, and state-based control logic is not found in existing literature.

[0006] Furthermore, the simple threshold comparison method causes chatter issues that induce frequent mode switching near the threshold, leading to reduced device lifespan and control instability.

[0007] Therefore, a new control structure is required that can stably switch cooling paths while comprehensively considering load and temperature conditions.

[0008] Since this configuration corresponds to a system state-based control structure rather than a simple change in cooling method, it cannot be easily derived by a person of ordinary skill. Prior art literature

[0010] Registered Patent No. 10-2009502 Multi-cooling fan module US Registered Patent No. US8380377 Method for controlling cooling of power converter for hybrid electric vehicle US Registered Patent No. US10968813 Hybrid cooling system and method thereof The problem to be solved

[0011] The present invention aims to provide a control system that minimizes cooling energy consumption and improves system reliability by automatically switching the cooling path according to the operating state of the power conversion module in order to solve the above problem.

[0012] In addition, the purpose is to comprehensively determine the state based on multiple sensor data such as load rate, dielectric temperature, and case temperature, and to determine the cooling mode by applying state-based control logic rather than simple threshold control.

[0013] In addition, another objective is to ensure the stability of mode switching and extend the lifespan of the cooling device through a control structure that includes hysteresis and a minimum holding time.

[0014] Since such a challenge is not solved by the simple combination of individual components but requires the organic integration of state-based decision logic and cooling control structures, there is no technical motivation.

[0015] The problems solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0017] The load-linked automatic cooling path switching control system according to the present invention includes a multi-sensor unit (110), a data processing unit (120), a control algorithm unit (130), and a cooling water flow rate control unit (140).

[0018] The above multi-sensor unit (110) measures the load rate, dielectric temperature, and case temperature in real time.

[0019] The above data processing unit (120) collects and normalizes the sensor data.

[0020] The control algorithm unit (130) determines the system state based on the data and determines the cooling mode.

[0021] The above control algorithm unit (130) maintains a natural convection cooling mode when the load rate is below a lower threshold, switches to a water cooling mode when it exceeds an upper threshold, and maintains the current state by applying hysteresis between thresholds.

[0022] The above natural convection cooling mode is defined not as a simple low-load cooling state, but as an independent operation mode capable of maintaining thermal equilibrium of the power conversion module without the operation of an external forced cooling device.

[0023] The above independent operation mode is configured to enable continuous normal operation within a certain load range and is utilized as a primary operation mode for improving system efficiency.

[0024] The above control algorithm unit (130) has a state-based control structure that performs state transitions based on a set of state variables including the system's current state, previous state, and dwell time, rather than a structure in which the control output is determined immediately by a simple threshold comparison.

[0025] Specifically, the control algorithm unit (130) is configured as a finite state machine structure including a first cooling mode (natural convection mode), a second cooling mode (water cooling mode), and a mode transition state, and the transition between each state is determined by a composite condition including a load rate (P), dielectric temperature (T_d), case temperature (T_c), and previous state information. The state transition is determined by a state transition function δ(state, input, history), and the transition function is defined to receive the load rate (P), dielectric temperature (T_d), case temperature (T_c), previous state (state_prev), and state retention time (t_dwell) as inputs and output a next state (state_next). The transition function is configured to perform different state transitions depending on the previous state and retention time even under the same input conditions.

[0026] Accordingly, it is configured so that different control results are derived depending on the previous state and state maintenance time, even under the same sensor input conditions.

[0027] The above cooling water flow rate control unit (140) controls the cooling water flow rate according to the determined cooling mode.

[0028] In addition, ramp control is performed to gradually increase the flow rate when entering water cooling mode.

[0029] Additionally, the load-linked automatic cooling path switching control system according to the present invention comprises: a multi-sensor unit (110) for measuring a plurality of state information including a load rate (P) of a power conversion module, a dielectric temperature (T_d), and a case temperature (T_c); a data processing unit (120) for collecting the plurality of state information and generating input data for control by removing noise, normalizing, or filtering; a control algorithm unit (130) for performing state transitions between cooling modes based on the input data for control and a set of state variables including (i) a current state, (ii) a previous state, and (iii) a state maintenance time, and determining a target flow rate according to a finite state machine structure including a natural convection cooling mode and a water cooling mode; and a cooling water flow rate control unit (140) for controlling a pump rotation speed, a valve opening rate, or a corresponding cooling water flow rate according to the target flow rate.

[0030] Preferably, the natural convection cooling mode is characterized by being defined as an independent operation mode that maintains thermal equilibrium of the power conversion module without driving an external forced cooling device.

[0031] Preferably, the control algorithm unit (130) is characterized by determining whether to switch modes using state history information including a previous cooling mode state and a mode maintenance time.

[0032] Preferably, the state transition is characterized by being performed according to a hysteresis condition using different upper and lower threshold values.

[0033] Preferably, the control algorithm unit (130) is characterized by controlling to maintain the same mode for a preset minimum maintenance time after the mode switch.

[0034] Preferably, the cooling water flow rate is controlled based on a target flow rate defined as a function of the load rate (P), dielectric temperature (T_d), and case temperature (T_c).

[0035] Preferably, the cooling water flow rate is characterized by including ramp control that gradually increases over time to reach a target flow rate.

[0036] Preferably, the data processing unit is characterized by being linked with multiple modules through a PMBus or EtherCAT interface. Effects of the invention

[0038] According to the present invention, the cooling energy consumption of the entire system can be minimized through load-linked cooling control.

[0039] In addition, since operation is possible using only natural convection cooling in low-load sections, energy for driving fans or pumps can be saved.

[0040] By reducing the frequency of mode switching through hysteresis and state maintenance logic, mechanical fatigue of the cooling device can be reduced and its lifespan extended.

[0041] In addition, thermal shock caused by sudden temperature changes can be prevented through ramp control.

[0042] Cooling control with higher accuracy than single-sensor-based control is possible through state determination based on multiple sensors.

[0043] Integrated control is possible in a data center environment by interoperating with higher-level systems through PMBus and EtherCAT interfaces.

[0044] The effects of the present invention are not limited to those mentioned above, and other unmentioned problems will be clearly understood by those skilled in the art from the description below. Brief explanation of the drawing

[0046] FIG. 1 is a block diagram of a system configuration according to an embodiment of the present invention. FIG. 2 is a cooling mode switching flowchart according to an embodiment of the present invention. FIG. 3 is a hysteresis graph according to an embodiment of the present invention. FIG. 4 is a communication interface configuration diagram according to an embodiment of the present invention. Specific details for implementing the invention

[0047] Further objects, features, and advantages of the present invention can be more clearly understood from the following detailed description and the accompanying drawings.

[0048] Before providing a detailed description of the present invention, it should be understood that the present invention is capable of various modifications and may have various embodiments, and that the examples described below and illustrated in the drawings are not intended to limit the present invention to specific embodiments, but rather include all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention.

[0049] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0050] The terms used in this specification are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0051] Furthermore, in the description referring to the attached drawings, identical components are assigned the same reference numeral regardless of drawing symbols, and redundant descriptions thereof are omitted. In describing the present invention, if it is determined that a detailed description of related prior art could unnecessarily obscure the essence of the present invention, such detailed description is omitted.

[0053] FIG. 1 shows an overall configuration block diagram of a load-linked automatic cooling path switching control system (100) according to one embodiment of the present invention.

[0054] Referring to FIG. 1, the control system (100) is configured to include a multi-sensor unit (110), a data processing unit (120), a control algorithm unit (130), and a cooling water flow rate control unit (140).

[0055] The above-mentioned multi-sensor unit (110) includes a plurality of sensors that reflect the operating state of the power conversion module, and specifically may include a load rate sensor, a dielectric temperature sensor, a case surface temperature sensor, and a cooling water inlet / outlet temperature sensor. This sensor configuration is intended to reflect multiple states rather than a single physical quantity, and is distinguished from simple temperature-based control.

[0056] The data processing unit (120) receives data collected from the multi-sensor unit (110) in real time through PMBus 1.3+ and EtherCAT interfaces, normalizes and filters the data, and transmits it to the control algorithm unit (130).

[0057] The control algorithm unit (130) determines a cooling mode based on a plurality of sensor data transmitted from the data processing unit (120) and performs state-based control logic including threshold comparison and hysteresis application.

[0058] In addition, the control algorithm unit (130) determines whether to switch modes using state history information including the previous mode state, mode maintenance time, and past temperature change history.

[0059] Accordingly, immediate mode switching caused by input fluctuations near a simple threshold is suppressed, and stable control reflecting the system's dynamic response characteristics is possible.

[0060] The above cooling water flow rate control unit (140) controls an electric valve or a variable speed pump according to a control signal of the above control algorithm unit (130) to regulate the cooling water flow rate, and accordingly, a natural convection cooling path or a water cooling path is selectively activated.

[0062] Figure 2 is a flowchart showing the cooling mode switching control logic of the present invention.

[0063] Referring to FIG. 2, first, the system performs the step (S210) of collecting sensor data.

[0064] Next, the system performs a first judgment step (S220) based on the load rate (P) and dielectric temperature (Td), and if the load rate is below the lower threshold value (TH_low) and the dielectric temperature is below the safe temperature (Tsafe), it enters a natural convection self-cooling mode (Mode 1) (S230).

[0065] If the above conditions are not satisfied, the system performs a second judgment step (S240), and switches to a hybrid water cooling mode (Mode 2) if the load rate exceeds an upper threshold (TH_high) or the dielectric temperature exceeds a warning temperature (Twarn) (S250).

[0066] In the interval between the two conditions above, a hysteresis interval (S260) is applied, and the current cooling mode is maintained.

[0067] Subsequently, the above control logic is continuously executed through a loop repetition step (S270).

[0068] The aforementioned hysteresis interval is intended to prevent repetitive mode switching near the threshold value and is a key component that is essentially distinct from simple threshold control.

[0069] In one embodiment of the present invention, the lower threshold (TH_low) may be set in the range of about 20% to 35% relative to the rated load of the power conversion module, and the upper threshold (TH_high) may be set in the range of about 60% to 85%. Here, TH_low is the lower load threshold and TH_high is the upper load threshold.

[0070] In addition, the safety temperature (Tsafe) can be set in the range of 50°C to 70°C based on the long-term stable operating temperature of the dielectric, and the warning temperature (Twarn) can be set in the range of 75°C to 95°C as the reference temperature for thermal stress occurrence. Here, Tsafe is the dielectric safety temperature, Twarn is the dielectric warning temperature, Tcase_safe is the case safety temperature, and Tcase_warn is the case warning temperature.

[0071] The above threshold values ​​can be determined through preliminary experiments or simulations based on the thermal capacity, cooling structure, and dielectric properties of the device.

[0072] Since the initial state may not be defined when the system is first started, initialization logic may be included to determine the default state based on the initial load rate and temperature conditions.

[0073] As an example, if the initial load rate is below a lower threshold, the natural convection mode may be set as the initial state, and if it is above an upper threshold, the water cooling mode may be set as the initial state.

[0075] Figure 3 is a graph showing the hysteresis-based cooling mode switching threshold relationship applied in the present invention.

[0076] Referring to Fig. 3, the horizontal axis represents the load rate (P), and the vertical axis represents the cooling mode.

[0077] When the load rate is below the lower threshold (TH_low), the system maintains a natural convection self-cooling mode (Mode 1).

[0078] On the other hand, if the load rate exceeds the upper threshold (TH_high), the system switches to hybrid water cooling mode (Mode 2).

[0079] The interval between the above TH_low and TH_high is defined as a hysteresis interval, and stability of the mode switch is ensured by maintaining the current cooling mode during this interval.

[0080] In particular, the transition from Mode 1 to Mode 2 and the return from Mode 2 to Mode 1 are based on different threshold values, thereby forming a transition hysteresis characteristic.

[0081] In one embodiment of the present invention, each cooling mode may be configured to have a minimum dwell time after switching.

[0082] For example, by limiting the maintenance of the same mode for 10 to 120 seconds after a mode switch, frequent mode switching (chattering) near the threshold can be prevented. The maintenance time can be set by considering the thermal response time of the system and the sensor noise characteristics. That is, the faster the thermal response speed of the system, the shorter the maintenance time is set.

[0083] This dual threshold structure is clearly distinct from a simple single threshold comparison structure and is an essential component for ensuring system stability.

[0084] When switched to water cooling mode, the coolant flow rate can be controlled via ramp control that increases linearly or in steps over time.

[0085] For example, stepwise control can be applied to increase the flow rate from an initial flow rate (Q0) to a target flow rate (Q_target) in 10% increments over 5 to 30 seconds.

[0086] Alternatively, it can be controlled in the form of a linear increasing function of Equation 1 with respect to time t, where T_ramp can be set in the range of 5 to 30 seconds. The T_ramp is set to a value greater than 0 and may include exception handling logic that corrects to a minimum value if it becomes 0 due to a setting error.

[0087]

[0088] In addition, the above-mentioned cooling water flow rate (Q) is not limited to a simple increasing function over time, but can be controlled based on a target flow rate (Q_target = f(P, T_d, T_c)) that is dynamically determined according to state variables including the load rate (P), dielectric temperature (T_d), and case temperature (T_c). That is, different target flow rates are set depending on the system state even under the same time elapsed conditions, and accordingly, the precision of cooling control is improved.

[0089] As an example, the target flow rate (Q_target) can be defined in the form of a weighted sum of Equation 2.

[0090]

[0091] Here, k1, k2, and k3 are weighting coefficients set according to system characteristics. The above weighting coefficients can be set through preliminary experiments or simulations.

[0092] The above-mentioned cooling water flow rate (Q) in water cooling mode is converted into a pump rotational speed (N) or valve opening rate (V) by a controller, and said conversion can be performed using a pre-set control map or a linear / non-linear functional relationship (Q=f(N), Q=f(V)).

[0093] Therefore, in the above formula, Q0 and Q_target represent the flow rate corresponding to the initial pump rotational speed or initial valve opening rate, and the flow rate corresponding to the target rotational speed or target opening rate, respectively.

[0094] The 'section' indicated in Fig. 3 refers to the operating area where each cooling mode is maintained, and the 'mode' refers to the control state, and they are distinguished from each other.

[0096] FIG. 4 is a configuration diagram showing the structure in which the control system (100) of the present invention is linked with a higher system.

[0097] Referring to FIG. 4, the control system (100) is connected to a data center management system via a PMBus 1.3+ interface to share sensor data in real time.

[0098] In addition, synchronization control between multiple power conversion modules is performed via the EtherCAT interface.

[0099] The above control system (100) is connected to a plurality of power conversion modules (#1 to #N) and performs integrated cooling control for each module.

[0100] In particular, consistent cooling operation without time delay between multiple modules is possible through EtherCAT-based synchronization control.

[0101] This high-level system integration structure is distinct from simple local cooling control systems and provides a structure that can be expanded into an integrated thermal management system at the data center level.

[0103] The embodiments described in this specification and the accompanying drawings are merely illustrative of a part of the technical concept included in the present invention. Accordingly, since the embodiments disclosed in this specification are intended to explain, not limit, the technical concept of the present invention, it is obvious that the scope of the technical concept of the present invention is not limited by these embodiments. All variations and specific embodiments that can be easily deduced by a person skilled in the art within the scope of the technical concept included in the specification and drawings of the present invention should be interpreted as being included within the scope of the rights of the present invention. Explanation of the symbols

[0105] 100: Load-linked automatic cooling path switching control system 110: Multi-sensor unit 111: Load rate sensor 112: Dielectric temperature sensor 113: Case temperature sensor 114: Coolant inlet temperature sensor 115: Coolant outlet temperature sensor 120 : Data processing unit 130: Control Algorithm Section 140: Cooling water flow control unit 200: Data Center Management System

Claims

Claim 1 A load-linked automatic cooling path switching control system comprising: a multi-sensor unit (110) for measuring a plurality of state information including a load rate (P), dielectric temperature (T_d), and case temperature (T_c) of a power conversion module; a data processing unit (120) for collecting the plurality of state information and generating input data for control by removing noise, normalizing, or filtering; a control algorithm unit (130) for performing state transitions between cooling modes based on the input data for control and a set of state variables including (i) current state, (ii) previous state, and (iii) state maintenance time, and determining a target flow rate according to a finite state machine structure including a natural convection cooling mode and a water cooling mode; and a cooling water flow rate control unit (140) for controlling a pump rotation speed, a valve opening rate, or a corresponding cooling water flow rate according to the target flow rate. Claim 2 A load-linked automatic cooling path switching control system according to claim 1, characterized in that the natural convection cooling mode is defined as an independent operation mode that maintains thermal equilibrium of the power conversion module without driving an external forced cooling device. Claim 3 A load-linked automatic cooling path switching control system according to claim 1 or 2, wherein the control algorithm unit (130) determines whether to switch modes using state history information including a previous cooling mode state and a mode maintenance time. Claim 4 A load-linked automatic cooling path switching control system according to claim 1, wherein the state transition is performed according to a hysteresis condition using different upper and lower threshold values. Claim 5 A load-linked automatic cooling path switching control system according to claim 1, wherein the control algorithm unit (130) controls the same mode to be maintained for a preset minimum maintenance time after the mode switching. Claim 6 A load-linked automatic cooling path switching control system according to claim 1, characterized in that the cooling water flow rate is controlled based on a target flow rate defined as a function of load rate (P), dielectric temperature (T_d), and case temperature (T_c). Claim 7 A load-linked automatic cooling path switching control system according to claim 6, characterized in that the cooling water flow rate includes ramp control that gradually increases over time to reach a target flow rate. Claim 8 A load-linked automatic cooling path switching control system according to claim 1, wherein the data processing unit is linked with multiple modules via a PMBus or EtherCAT interface.

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