JP2021035296A - Coolant warmup control device of electric vehicle - Google Patents

Abstract

To achieve cost reduction and space saving, in a coolant warmup control device of an electric vehicle.SOLUTION: A coolant warmup control device 1 of an electric vehicle 10 which is driven by supplying power from a battery to a traveling motor via an inverter 13 includes a warmup circuit 2 in which a coolant 3 which is formed so as to be heat-exchangeable with a warmup object 14 having a warmup function circulates, and an active discharge resistor 6 arranged in a high-voltage circuit 4 in the inverter 13, and used for discharging an electric charge of the high-voltage circuit 4 when the electric vehicle 10 is stopped. Also, the coolant warmup control device 1 includes a heat-exchanging part 7 which can exchange heat between the coolant 3 circulating in the warmup circuit 2 and the active discharge resistor 6, and a warmup control part 8 for raising a temperature of the coolant 3 up to a desired temperature by controlling a power amount which is consumed by the active discharge resistor 6, and controlling a heat exchange amount between the coolant 3 in the heat exchanger part 7 and the active discharge resistor 6.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a coolant warm-up control device for warming the coolant of an electric vehicle.

In recent years, from the viewpoint of reducing the burden on the environment, electric vehicles that are not equipped with an internal combustion engine and are driven only by an electric motor have been developed. Whereas conventional vehicles equipped with an internal combustion engine use an internal combustion engine as a heat source for warming up in-vehicle components and heating air conditioning, electric vehicles do not have an internal combustion engine, so an electric heater as a warming device. May be installed. For example, it has been proposed to use a PTC heater to heat an in-vehicle battery (see Patent Document 1).

Japanese Unexamined Patent Publication No. 7-14369

However, the electric heater as described above is relatively expensive and requires a predetermined mounting space. For this reason, electric vehicles are required to reduce the cost and space of the warm-up configuration.

The coolant warm-up control device for an electric vehicle of the present disclosure was devised in view of the above-mentioned problems, and one of the purposes is to realize cost reduction and space saving.

The coolant warm-up control device for an electric vehicle disclosed here is a coolant warm-up control device for an electric vehicle that is driven by supplying electric power from a battery to a traveling motor via an inverter, and is covered by the electric vehicle. A warm-up circuit that circulates coolant that is configured to be heat-exchangeable with the warm-up object and a high-voltage circuit in the inverter that discharges the charge of the high-voltage circuit when the electric vehicle stops. The active discharge resistor used for this purpose, the heat exchange unit that enables heat exchange between the coolant circulating in the warm-up circuit and the active discharge resistor, and the power consumed by the active discharge resistor. A warm-up control unit that warms the temperature of the coolant to a desired temperature by controlling the amount of heat exchange between the coolant and the active discharge resistor in the heat exchange unit is included.

By heat exchange between the active discharge resistor provided in the high voltage circuit in the inverter and the coolant circulating in the warm-up circuit, the coolant is heated by utilizing the heat of the active discharge resistor for discharge. Therefore, cost reduction and space saving can be achieved while enabling warming of the object to be warmed.

According to the coolant warm-up control device for the electric vehicle of the present disclosure, cost reduction and space saving can be realized.

It is a schematic block diagram of an electric vehicle. It is a schematic diagram which shows the coolant warm-up control device of an electric vehicle as an embodiment.

A coolant warm-up control device for an electric vehicle as an embodiment will be described with reference to the drawings. The embodiments shown below are merely examples, and there is no intention of excluding the application of various modifications and techniques not specified in this embodiment. Each configuration of the following embodiments can be variously modified and implemented without departing from their gist. In addition, it can be selected as needed, or can be combined as appropriate.

[1. Constitution]
The coolant warm-up control device 1 (hereinafter, simply referred to as “control device 1”) of the electric vehicle of the present embodiment is applied to the electric vehicle 10 shown in FIG. The electric vehicle 10 is, for example, a truck, and converts a direct current and an alternating current between a battery 11 that can store electricity, a traveling motor 12 that rotates with the electric power of the battery 11, and the battery 11 and the traveling motor 12. It is equipped with an inverter 13. The electric vehicle 10 is driven (traveled) by supplying the electric power of the battery 11 to the traveling motor 12 via the inverter 13. The electric vehicle 10 is not equipped with an internal combustion engine.

As shown in FIG. 2, the electric vehicle 10 is provided with a warm-up circuit 2 for warming the warm-up object 14 as needed. Specifically, the warm-up circuit 2 is a passage through which the coolant 3 configured to exchange heat with the object to be warmed 14 circulates. In FIG. 2, the coolant 3 is schematically shown by an arrow.

The warm-up circuit 2 may have a function of cooling the warm-up object 14 with the coolant 3 in addition to the function of warming the warm-up object 14 with the coolant 3. For example, for the warmed object 14 that generates heat during operation, the warmed object 14 before or immediately after the start is heated by the coolant 3, and the warmed object 14 after the heat is generated by the coolant 3. The warm-up circuit 2 may be configured to cool.

Further, the object to be warmed 14 referred to here is an in-vehicle device that needs to be heated when, for example, the electric vehicle 10 is used in an extremely cold environment. Specific examples of the object to be warmed 14 include a battery 11, a traveling motor 12, and a heating circuit (not shown) of an in-vehicle air conditioning system.
A high-voltage circuit 4 for supplying electric power to the traveling motor 12 is arranged in the inverter 13. In addition to the battery 11, the high-voltage circuit 4 is provided with a high-voltage capacitor 5 that stores and discharges electric charges, and an active discharge resistor 6 that generates heat by consuming electric power.

The active discharge resistor 6 has a function as a safety device used to discharge the electric charge of the high voltage circuit 4 when the electric vehicle 10 is stopped due to parking or an accident. Specifically, the active discharge resistor 6 suppresses the output voltage of the high voltage circuit 4 by consuming the electric power stored in the high voltage capacitor 5 when the electric vehicle 10 is stopped. The calorific value of the active discharge resistor 6 corresponds to the amount of electric power consumed by the active discharge resistor 6 (current passing through the active discharge resistor 6).
When the electric vehicle 10 is stopped, for example, the electric vehicle 10 is parked, a collision accident occurs in the electric vehicle 10, or an abnormality or failure occurs in the device connected to the high voltage circuit 4. For example, when it occurs.

The control device 1 enables heat exchange between the warm-up circuit 2 described above, the active discharge resistor 6 described above, the coolant 3 circulating in the warm-up circuit 2, and the active discharge resistor 6. A unit 7 and a warm-up control unit 8 that controls the amount of power consumed by the active discharge resistor 6 are included.
In the heat exchange unit 7 of the present embodiment, a part of the warm-up circuit 2 and the active discharge resistor 6 are arranged close to each other so that the coolant 3 and the active discharge resistor 6 can exchange heat with each other. It is composed of. However, the configuration of the heat exchange unit 7 is not limited to this, and for example, a heat exchanger that enables indirect heat exchange between the coolant 3 and the active discharge resistor 6 is applied as the heat exchange unit 7. You may.

Specifically, the warm-up control unit 8 controls the amount of heat exchange between the coolant 3 and the active discharge resistor 6 in the heat exchange unit 7 by controlling the current flowing into the active discharge resistor 6. As a result, the warm-up control unit 8 warms up the temperature T of the coolant 3 to a desired temperature To. Although the warm-up control unit 8 provided inside the inverter 13 is illustrated in the present embodiment, the warm-up control unit 8 may be provided outside the inverter 13.

For example, when the temperature T of the coolant 3 is less than the desired temperature To (T <To), the warm-up control unit 8 controls the high voltage circuit 4 so that the current flows to the active discharge resistor 6, and the coolant When the temperature T of 3 is equal to or higher than the desired temperature To (T ≧ To), the high voltage circuit 4 is controlled so that the current does not flow to the active discharge resistor 6.

[2. Action, effect]
The control device 1 controls a heat exchange unit 7 that enables heat exchange between the coolant 3 that circulates in the warm-up circuit 2 and the active discharge resistor 6, and a heat exchange amount in the heat exchange unit 7. This includes a warm-up control unit 8 that warms the temperature T of the coolant 3 to a desired temperature To. Therefore, the coolant 3 can be heated by utilizing the heat of the active discharge resistor 6 equipped as a safety device in the high voltage circuit 4. Therefore, the object 14 to be warmed can be warmed up by the coolant 3 heated by the heat of the active discharge resistor 6. Further, since it is not necessary to provide an electric heater for heating the coolant 3, cost reduction and space saving can be realized.

It is generally known that power semiconductor elements such as IGBTs and SiCs provided in an inverter generate heat when switching is controlled. Therefore, it is conceivable to use these power semiconductor elements as a heat source for heating the above-mentioned object to be warmed.
However, since the power semiconductor element is driven according to the traveling control of the vehicle, when the heat generation amount of the power semiconductor element is controlled in response to the warm-up request of the object 14 to be warmed, the traveling of the vehicle is performed. May affect the condition.

For example, when a power semiconductor element is used as a heat source for the coolant 3, switching control of the power semiconductor element may be performed in response to a warm-up request for the object to be warmed 14 even though there is no drive request for the inverter 13. , There is a risk that the traveling safety may be lowered due to the unintended driving of the traveling motor 12.
Further, when the power semiconductor element is used as the heat source of the coolant 3, if the switching control of the power semiconductor element is performed in response to the drive request of the inverter 13 even though there is no warm-up request for the object to be warmed 14. , The coolant 3 is unnecessarily heated. Therefore, when the coolant 3 is used for cooling the object to be warmed, the energy efficiency may be lowered.

On the other hand, according to the control device 1, the active discharge resistor 6 as a safety device provided in the high voltage circuit 4 in the inverter 13 is used as a heat source for heating the object to be warmed. To. Therefore, the calorific value of the active discharge resistor 6 can be controlled independently of the traveling control of the electric vehicle 10. Therefore, it is possible to warm up the object to be warmed up 14 without causing the above-mentioned decrease in running stability and energy efficiency.

[3. Modification example]
The configuration of the warm-up circuit 2 described above is an example. When the warm-up circuit 2 also has a function of cooling the object to be warmed 14, a radiator for releasing the heat of the coolant 3 may be further provided in the warm-up circuit 2.
The configuration of the high voltage circuit 4 is also an example.

The content of control in the warm-up control unit 8 is not limited to the above. The warm-up control unit 8 sets the high voltage circuit 4 so that, for example, the larger the difference (To−T) between the temperature T of the coolant 3 and the desired temperature To, the larger the current flowing through the active discharge resistor 6. It may be controlled. Further, the warm-up control unit 8 may start controlling the amount of electric power consumed by the active discharge resistor 6 based on conditions other than the temperature T of the coolant 3.

Further, the temperature T of the coolant 3 used in the control by the warm-up control unit 8 may be directly detected from the coolant 3 by a temperature sensor or the like, or may be estimated (calculated) from other parameters. Further, the desired temperature To may be appropriately set according to the appropriate temperature required for the object to be warmed.

1 Control device (coolant warm-up control device)
2 Warm-up circuit 3 Coolant 4 High-voltage circuit 5 High-voltage capacitor 6 Active discharge resistor 7 Heat exchange unit 8 Warm-up control unit 10 Electric vehicle 11 Battery 12 Traveling motor 13 Inverter 14 Heated object T Coolant temperature To desired temperature

Claims (1)

A coolant warm-up control device for an electric vehicle that is driven by supplying electric power from a battery to a traveling motor via an inverter.
A warm-up circuit that circulates coolant that is configured to exchange heat with the warm-up object of the electric vehicle, and
An active discharge resistor provided in the high-voltage circuit in the inverter and used to discharge the electric charge of the high-voltage circuit when the electric vehicle is stopped.
A heat exchange unit that enables heat exchange between the coolant circulating in the warm-up circuit and the active discharge resistor.
By controlling the amount of power consumed by the active discharge resistor and controlling the amount of heat exchange between the coolant and the active discharge resistor in the heat exchange unit, the temperature of the coolant is warmed up to a desired temperature. Including warm-up control unit,
Coolant warm-up control device for electric vehicles.

Images