JP2022138411A - Flow rate estimation device, vehicle and flow rate estimation method - Google Patents

Abstract

A flow rate estimating device, a vehicle, and a flow rate estimating method capable of accurately estimating the flow rate of a refrigerant are provided.
A flow rate estimating device includes a heat generating part that generates heat in accordance with an output power amount, a cooling part that configures a flow path in which a coolant for cooling the heat generating part flows through a portion corresponding to an arrangement location of the heat generating part, A first temperature detection unit that detects a first temperature upstream of the cooling unit relative to the heat generating unit in the flow direction of the coolant, and a second temperature detecting unit that detects a second temperature downstream of the cooling unit relative to the heat generating unit in the flow direction. A detection unit and an estimation unit that estimates the flow rate of the coolant in the cooling unit based on the temperature difference between the second temperature and the first temperature.
[Selection drawing] Fig. 1

Description

The present disclosure relates to a flow rate estimation device, a vehicle, and a flow rate estimation method.

In a charger (power conversion device) mounted on a vehicle, it is necessary to maintain a high power density, so a heating element (heat generating portion) that generates heat when energized tends to overheat. In the power conversion device, a flow path (cooling section) through which a coolant for cooling the heat generating section flows is provided in order to prevent the elements from being destroyed due to overheating of the heat generating section. Since the amount of heat generated by the heat generating section changes according to the output power amount of the heat generating section, it is necessary to accurately manage the flow rate of the coolant in the cooling section.

In order to measure the flow rate of the refrigerant in the flow path, for example, it is common to install a flow meter inside the flow path. is desirable.

A method of estimating the flow rate of the refrigerant includes a method of detecting the temperature of the refrigerant by providing a temperature detection unit. For example, Patent Literature 1 discloses a configuration that detects the temperature of the coolant by providing a temperature sensor near the outlet of the coolant in the flow path, and controls the flow rate of the coolant based on the detected temperature. .

JP 2020-145793 A

However, when estimating the flow rate of the refrigerant using the detection result of one temperature detection unit provided in the flow path (cooling section), it is only possible to distinguish whether the refrigerant is flowing or not, and the estimation accuracy of the flow rate of the refrigerant is limited. There were limits.

An object of the present disclosure is to provide a flow rate estimation device, a vehicle, and a flow rate estimation method capable of accurately estimating the flow rate of refrigerant.

The flow rate estimation device according to the present disclosure is
a heating unit that generates heat according to the amount of output electric power;
a cooling part that configures a flow path through which a coolant for cooling the heat generating part flows through a portion corresponding to an arrangement location of the heat generating part;
a first temperature detection unit that detects a first temperature on the upstream side of the cooling unit relative to the heat generating unit in the flow direction of the coolant;
a second temperature detection unit that detects a second temperature downstream of the cooling unit relative to the heat generating unit in the flow direction;
an estimation unit that estimates the flow rate of the refrigerant in the cooling unit based on the temperature difference between the second temperature and the first temperature;
Prepare.

A vehicle according to the present disclosure includes:
It comprises the flow estimation device described above.

A flow rate estimation method according to the present disclosure includes:
Flow rate estimation of a flow rate estimating device comprising: a heat generating part that generates heat in accordance with an output power amount; a method,
detecting a first temperature upstream of the cooling unit relative to the heat generating unit in the flow direction of the coolant;
detecting a second temperature downstream of the cooling section relative to the heat generating section in the flow direction;
A flow rate of the coolant in the cooling unit is estimated based on the temperature difference between the second temperature and the first temperature.

According to the present disclosure, the refrigerant flow rate can be accurately estimated.

1 is a block diagram showing a configuration example of a vehicle to which a power converter according to an embodiment of the present disclosure is applied; FIG. It is a figure which shows the structure of a cooling part. It is a flowchart which shows the operation example of the flow estimation control in a power converter device.

(Embodiment)
Hereinafter, embodiments of the present disclosure will be described in detail based on the drawings. FIG. 1 is a block diagram showing a configuration example of a vehicle 1 to which a power conversion device 100 according to an embodiment of the present disclosure is applied.

As shown in FIG. 1, the power conversion device 100 is connected to an external AC power supply 2 outside the vehicle 1, and converts AC power supplied from the external AC power supply 2 into DC power to charge the battery 3. is. The battery 3 is, for example, a battery mounted in a vehicle 1 such as an electric vehicle or a hybrid vehicle.

The power conversion device 100 includes an AC filter 110, a rectification unit 120, a power conversion unit 130, a cooling unit 140 (see FIG. 2), a first temperature detection unit 150, a second temperature detection unit 160, an output power detection unit 170, and a control unit. 180 and the like. The power electronics device 100 corresponds to the "flow rate estimation device" of the present disclosure.

AC filter 110 is provided on a power line between external AC power supply 2 and rectifying section 120 and power converting section 130 .

The AC filter 110 is made up of parts such as capacitors and reactors, and serves to remove noise superimposed on the power line so that it does not flow out to the external AC power supply 2 . The AC filter 110 also plays a secondary role of removing noise superimposed on the AC power input from the external AC power supply 2 .

The rectifying unit 120 has, for example, a diode bridge circuit composed of four diodes, performs full-wave rectification of the AC power output from the external AC power supply 2, converts it into DC power, and outputs the DC power to the power converting unit 130. .

Power conversion section 130 includes power conversion circuits such as a power factor correction circuit and a DC/DC conversion circuit. The power factor correction circuit improves the power factor of the DC power input from rectifying section 120 . The DC/DC conversion circuit has a switching element, and converts the DC power output by the power factor correction circuit into DC power capable of charging the battery 3 by switching the switching element. The battery 3 is charged by outputting the DC power converted by the power conversion unit 130 in this manner to the battery 3 .

As shown in FIG. 2, each part of the power conversion device 100 is housed in one housing 101 formed by die casting, and constitutes a heat generating part 102 that generates heat according to the output power amount of the power conversion device 100. do. The heat generating unit 102 is a circuit block of the power conversion device 100, such as the AC filter 110, the rectification unit 120, and the power conversion unit 130, which are arranged on the substrate. It contains a heating element that generates heat. A cooling unit 140 that cools the heat generating unit 102 is provided in the housing 101 .

The cooling part 140 constitutes a channel through which a coolant (for example, a fluid such as water) for cooling the heat generating part 102 flows, and has, for example, a groove shape formed in the bottom wall of the housing 101 . Specifically, cooling unit 140 has a first portion 140A, a second portion 140B and a third portion 140C.

The first portion 140A is a channel extending from an inflow port 141 formed in a predetermined side wall 101A of the housing 101, and is located upstream of the second portion 140B in the coolant flow direction.

The second portion 140B is a flow path located in a portion corresponding to the location where the heat generating portion 102 is arranged, and is configured to have a size that allows the entire heat generating portion 102 to be cooled by the coolant.

The third portion 140C is a flow path extending from the second portion 140B to an outlet 142 formed in a predetermined side wall 101A at a position different from the inlet 141, and downstream of the second portion 140B in the flow direction of the coolant. located on the side.

Cooling unit 140 is arranged such that a portion of housing 101 that constitutes cooling unit 140 is in contact with heat generating unit 102 . As a result, the coolant flows into the cooling portion 140, the coolant that has flowed into the first portion 140A enters the second portion 140B, the heat of the heat generating portion 102 is transferred to the coolant, and the coolant flows out to the third portion 140C. It has become.

A circulation path (not shown) connecting the inlet 141 and the outlet 142 is provided outside the housing 101 . The coolant circulates through the cooling unit 140 and the circulation path, for example, when a pump or the like is controlled by an ECU (Electronic Control Unit) 4 of the vehicle 1 .

The ECU 4 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an input/output circuit (not shown), and controls the flow rate of coolant flowing through the cooling section 140 .

Under the control of the ECU 4 , the coolant that has flowed in from the inlet 141 passes through a portion of the cooling section 140 corresponding to the location where the heat generating section 102 is arranged. flow out from Thereby, the cooling unit 140 cools the heat generating unit 102 .

The first temperature detection unit 150 and the second temperature detection unit 160 are temperature sensors that detect the temperature of the coolant flowing through the cooling unit 140. For example, the substrate on which the heat generating unit 102 is arranged contacts the cooling unit 140. are placed. Note that the first temperature detection unit 150 and the second temperature detection unit 160 may be arranged in any way as long as the temperature of the coolant in the cooling unit 140 can be detected.

The first temperature detection unit 150 detects a first temperature on the upstream side of the cooling unit 140 relative to the heat generating unit 102 in the flow direction of the coolant in the cooling unit 140 . The first temperature detection unit 150 is arranged at a position (position of the first portion 140A) corresponding to the upstream side of the cooling unit 140 relative to the heat generating unit 102 in the housing 101 . Specifically, the first temperature detection unit 150 is arranged at a position corresponding to the inlet 141 in the housing 101 .

The second temperature detection section 160 detects a second temperature downstream of the cooling section 140 relative to the heat generating section 102 in the flow direction. The second temperature detection unit 160 is arranged at a position (position of the third portion 140C) corresponding to the downstream side of the cooling unit 140 relative to the heat generating unit 102 in the housing 101 . Specifically, the second temperature detection unit 160 is arranged at a position corresponding to the outflow port 142 in the housing 101 .

The output power detection unit 170 is a sensor such as a voltage sensor or a current sensor that can detect the amount of power, and detects the amount of power output from the heat generating unit 102 .

Control unit 180 includes a CPU, ROM, RAM, and an input/output circuit (not shown), and estimates the flow rate of coolant flowing through cooling unit 140 based on a preset program. Control unit 180 corresponds to the “estimation unit” of the present disclosure.

The control unit 180 acquires first temperature information from the first temperature detection unit 150 and acquires second temperature information from the second temperature detection unit 160 . Control unit 180 estimates the flow rate of coolant in cooling unit 140 based on the temperature difference between the first temperature and the second temperature.

Specifically, control unit 180 estimates the flow rate of coolant in cooling unit 140 based on the temperature difference between the first temperature and the second temperature and the heat generation state of heat generating unit 102 . For example, the information on the heat generation state of the heat generation unit 102 is the detection result of the output power amount of the heat generation unit 102 acquired from the output power detection unit 170 .

Since the first temperature is the temperature of the coolant when it flows into the housing 101, it is the temperature of the coolant before it passes through the location where the heat generating section 102 is arranged. On the other hand, the second temperature is the temperature when the coolant flows out to the housing 101, so it is the temperature of the coolant after passing through the location where the heat generating section 102 is arranged.

Therefore, since the second temperature is the temperature of the refrigerant that has absorbed the heat of the heat generating section 102, the temperature is higher than the first temperature. temperature difference increases.

In addition, since there is a relationship that the more the flow rate of the refrigerant increases, the smaller the temperature change becomes. , it is possible to calculate the flow rate of the refrigerant.

For example, since the amount of heat generated by the heat generating unit 102 and the amount of output power of the heat generating unit 102 are in a proportional relationship, it is possible to estimate the amount of heat generated by the heat generating unit 102 from the amount of output power. Therefore, the control unit 180 estimates the flow rate of the coolant from the amount of heat generated and the temperature difference between the second temperature and the first temperature using a theoretical formula and an empirical formula showing the relationship between the flow rate of the coolant. .

Theoretical formulas and empirical formulas showing the relationship between the amount of heat generated by the heat generating unit 102, the temperature difference between the second temperature and the first temperature, and the flow rate of the coolant are based on the characteristics of the housing 101, the shape of the cooling unit 140, and the heat generation. It is an expression that can be appropriately determined according to experiments, simulations, or the like, taking into consideration the arrangement position of the unit 102 .

Here, the flow rate of the refrigerant is estimated from the amount of heat generated by the heat generating section 102 and the temperature difference between the second temperature and the first temperature. Alternatively, the flow rate of the coolant may be estimated from the temperature difference between the second temperature and the first temperature using a theoretical formula and an empirical formula showing the relationship with the flow rate of the coolant.

Thus, in this embodiment, it is possible to accurately estimate the flow rate of the refrigerant. Then, the control unit 180 compares the estimated flow rate with the target flow rate. The target flow rate is the flow rate of the coolant determined based on the amount of heat generated by the heat generating section 102, and is the flow rate of the coolant that can cool the heat generating section 102 to an appropriate temperature.

The control unit 180 performs control to stop the power conversion device 100 according to the comparison result between the target flow rate and the estimated flow rate. Specifically, the control unit 180 performs control to stop the power conversion device 100 when the estimated flow rate is excessively small with respect to the target flow rate. The control unit 180 corresponds to the "stop control unit" of the present disclosure.

The estimated flow rate being excessively low relative to the target flow rate means, for example, that the estimated flow rate is low relative to the target flow rate, making it impossible to properly cool the heat-generating part 102, and possibly destroying the heat-generating element. .

As a result, the operation of the power conversion device 100 is stopped, so that the breakage of the heating element due to the overheating of the heating unit 102 can be suppressed.

In addition, when the operation of the power conversion device 100 is stopped, the ECU 4 provides the user (driver) with information indicating that the charging operation of the power conversion device 100 cannot be performed, or information indicating that replacement of parts such as a pump is urged. Execute the notification control.

As a result, the user can quickly recognize that the charging operation of the battery 3 is not being performed, and the user can quickly perform appropriate part replacement.

Also, the control unit 180 outputs a command to the ECU 4 to adjust the flow rate of the refrigerant according to the comparison result between the target flow rate and the estimated flow rate. Specifically, even if there is a difference between the target flow rate and the estimated flow rate, if the ECU 4 can adjust the flow rate of the coolant, the control unit 180 outputs a command to adjust the flow rate of the coolant to the ECU 4 .

When the ECU 4 acquires a command to adjust the flow rate of the refrigerant from the control unit 180, the ECU 4 adjusts the flow rate of the refrigerant based on the estimated flow rate so that the flow rate of the refrigerant reaches the target flow rate.

By doing so, when there is a difference between the estimated flow rate of the coolant actually flowing through the cooling unit 140 and the target flow rate, the coolant can flow through the cooling unit 140 at an appropriate flow rate.

Further, depending on the outside air temperature of the vehicle 1, the temperature state resulting from the heat generation of the heat generating portion 102 changes. For example, when the outside air temperature is lower than normal temperature, the temperature of heat generating unit 102 is lower than that at normal temperature even if the output power amount of heat generating unit 102 is the same as at normal temperature. Therefore, the flow rate of the refrigerant may be less than at room temperature. Further, when the outside air temperature is higher than the room temperature, the temperature of the heat generating part 102 becomes higher than that at the room temperature even if the output power amount of the heat generating part 102 is the same as at the room temperature. Therefore, it is necessary to increase the flow rate of the refrigerant more than at room temperature.

Therefore, the control unit 180 may output to the ECU 4 a command to change the target flow rate of the coolant flowing through the cooling unit 140 according to the outside air temperature. The control unit 180 corresponds to the "change unit" of the present disclosure. Information on the outside air temperature is acquired by the control unit 180 based on temperature information from a temperature detection unit capable of detecting the ambient temperature of the power conversion device 100, temperature information transmitted from an external device to the vehicle 1, or the like.

When the ECU 4 acquires a command to change the target flow rate, the ECU 4 changes the target flow rate of the coolant flowing through the cooling unit 140 and adjusts the flow rate of the coolant so as to achieve the changed target flow rate.

Specifically, the ECU 4 decreases the target flow rate as the outside air temperature is lower than normal temperature, and increases the target flow rate as the outside air temperature is higher than normal temperature.

By doing so, it is possible to set the flow rate of the refrigerant suitable for the temperature state of the heat generating portion 102 .

An operation example of flow rate estimation control in the power conversion device 100 configured as described above will be described. FIG. 3 is a flow chart showing an operation example of flow rate estimation control in the power converter 100 . The process in FIG. 3 is appropriately executed, for example, when the charging operation of the battery 3 in the power converter 100 is started.

As shown in FIG. 3, the controller 180 acquires a first temperature and a second temperature (step S101). After obtaining the first temperature and the second temperature, the controller 180 calculates the temperature difference between the second temperature and the first temperature (step S102). After calculating the temperature difference, the controller 180 estimates the flow rate of the coolant based on the temperature difference (step S103).

Next, the control unit 180 determines whether or not the difference between the estimated flow rate and the target flow rate is large (step S104). As a result of the determination, when the difference between the estimated flow rate and the target flow rate is large (step S104, YES), the control unit 180 stops the operation of the power converter 100 (step S105). After step S105, this control ends.

On the other hand, if the difference between the estimated flow rate and the target flow rate is not large (step S104, NO), the control unit 180 determines whether charging of the battery 3 is completed (step S106). Whether or not to adjust the flow rate of the refrigerant is separately determined according to the difference between the estimated flow rate and the target flow rate.

As a result of determination, when charging is not completed (step S106, NO), the process returns to step S101. On the other hand, when charging is completed (step S106, YES), this control ends.

According to the present embodiment configured as described above, the flow rate of the refrigerant is estimated based on the temperature difference between the second temperature and the first temperature. In other words, the flow rate of the coolant is estimated based on the temperature difference between the temperature on the upstream side of the heat generating section 102 in the cooling section 140 and the temperature on the downstream side thereof.

Accordingly, the flow rate of the coolant can be estimated in consideration of the temperature change of the coolant caused by the temperature state of the heat generating section 102 . As a result, it is possible to accurately estimate the flow rate of the refrigerant, and thus to suppress the destruction of the heating element due to the overheating of the heat generating section 102 .

Moreover, since the flow rate of the coolant is estimated based on the temperature state of the heat generating portion 102 and the temperature change of the coolant, the flow rate of the coolant can be estimated more accurately.

Further, since the first temperature detection unit 150 is arranged at a position corresponding to the inlet of the housing 101 and the second temperature detection unit 160 is arranged at a position corresponding to the outlet of the housing 101, The first temperature detection section 150 and the second temperature detection section 160 are arranged at positions where it is easy to create a temperature difference between the second temperature and the first temperature. As a result, it is possible to accurately detect the temperature difference between the second temperature and the first temperature, thereby improving the accuracy of estimating the flow rate of the refrigerant.

In addition, since the power conversion device 100 is stopped according to the result of comparison between the estimated flow rate and the target flow rate, it is possible to suppress breakage of the heating element due to overheating of the heating section 102 .

In the above embodiment, the first temperature detection section is arranged at a position corresponding to the inlet of the housing, and the second temperature detection section is arranged at a position corresponding to the outlet of the housing. The disclosure is not so limited. For example, as long as the first temperature detection section is arranged at a position corresponding to the upstream side of the heat generating section, and the second temperature detection section is arranged at a position corresponding to the downstream side of the heat generating section, any position is possible. It may be arranged.

Further, in the above embodiment, the control unit serves as the estimation unit, the stop control unit, and the change unit, but the present disclosure is not limited to this, and the ECU serves as the estimation unit, the stop control unit, and the change unit. Alternatively, the ECU may have part of the functions of the estimating section, the stop control section, and the changing section. Alternatively, the estimating unit, the stop control unit, and the changing unit may be separately provided.

Further, in the above-described embodiment, the cooling unit has the first portion, the second portion, and the third portion, but the present disclosure is not limited to this. Any configuration may be used.

Further, in the above embodiment, the cooling part has a groove shape, but the present disclosure is not limited to this, and any shape may be used as long as the shape allows cooling of the heat generating part by flowing a coolant. can be

Further, in the above embodiment, the power conversion device (charger) was exemplified as the flow rate estimation device, but the present disclosure is not limited to this. device may be used.

Further, in the above-described embodiment, the flow rate estimation device is mounted on the vehicle, but the present disclosure is not limited to this, and it may not be mounted on the vehicle.

In addition, each of the above-described embodiments merely shows an example of implementation for carrying out the present disclosure, and the technical scope of the present disclosure should not be construed to be limited by these. That is, the present disclosure can be embodied in various forms without departing from its spirit or key features.

INDUSTRIAL APPLICABILITY The flow rate estimation device of the present disclosure is useful as a flow rate estimation device, a vehicle, and a flow rate estimation method capable of accurately estimating the flow rate of refrigerant.

1 Vehicle 2 External AC Power Supply 3 Battery 4 ECU
REFERENCE SIGNS LIST 100 power conversion device 101 housing 102 heat generation section 110 AC filter 120 rectification section 130 power conversion section 140 cooling section 140A first section 140B second section 140C third section 141 inlet 142 outlet 150 first temperature detection section 160 second second Temperature detection unit 170 Output power detection unit 180 Control unit

Claims (9)

a heating unit that generates heat according to the amount of output electric power;
a cooling part that configures a flow path through which a coolant for cooling the heat generating part flows through a portion corresponding to an arrangement location of the heat generating part;
a first temperature detection unit that detects a first temperature on the upstream side of the cooling unit relative to the heat generating unit in the flow direction of the coolant;
a second temperature detection unit that detects a second temperature downstream of the cooling unit relative to the heat generating unit in the flow direction;
an estimation unit that estimates the flow rate of the refrigerant in the cooling unit based on the temperature difference between the second temperature and the first temperature;
A flow rate estimation device comprising: The estimation unit estimates the flow rate based on the temperature difference and the heat generation state of the heat generation unit.
The flow estimation device according to claim 1. A power detection unit that detects the output power amount of the heat generating unit,
The estimation unit acquires information on the heat generation state based on the detection result of the power detection unit.
The flow rate estimation device according to claim 2. A housing containing the heat generating unit and having the cooling unit,
The first temperature detection unit is arranged at a position corresponding to the upstream side of the cooling unit in the housing,
The second temperature detection unit is arranged at a position corresponding to the downstream side of the cooling unit in the housing,
A flow rate estimation device according to any one of claims 1 to 3. The housing is provided with an inflow port for the coolant in the cooling unit and an outflow port for the coolant in the cooling unit,
The first temperature detection unit is arranged at a position corresponding to the inlet in the housing,
The second temperature detection unit is arranged at a position corresponding to the outlet in the housing,
The flow rate estimation device according to claim 4. A stop control unit that stops the operation of the heat generation unit according to a comparison result between the estimated flow rate estimated by the estimation unit and a target flow rate,
The flow rate estimation device according to any one of claims 1 to 5. A changing unit that changes a target flow rate of the refrigerant flowing to the cooling unit according to an outside temperature,
A flow rate estimation device according to any one of claims 1 to 6. Equipped with the flow rate estimation device according to any one of claims 1 to 7,
vehicle. Flow rate estimation of a flow rate estimating device comprising: a heat generating part that generates heat in accordance with an output power amount; a method,
detecting a first temperature upstream of the cooling unit relative to the heat generating unit in the flow direction of the coolant;
detecting a second temperature downstream of the cooling section relative to the heat generating section in the flow direction;
A flow rate estimation method for estimating the flow rate of the coolant in the cooling unit based on the temperature difference between the second temperature and the first temperature.

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