CN103538482A - Automobile start-stop system capable of providing assisting power and recycling braking energy - Google Patents

Abstract

The utility model relates to an automobile start-stop system capable of boosting power and recovering braking energy, which belongs to the field of automobile control devices. The first port of the unidirectional step-down converter is an output port connected to the battery and the starter at the same time; the second port of the unidirectional step-down converter is an input port connected to the supercapacitor and the DC terminal of the motor controller in the BSG unit; The motor in the BSG unit is an AC motor, which is connected to the AC terminal of the motor controller; the motor is an electric/power generation integrated motor connected to the engine through a belt. The motor and the motor controller constitute the BSG unit, and the motor controller can transmit electric energy in both directions. In addition to realizing the function of starting and stopping the engine, the invention can effectively provide power assistance and recover the braking energy of the automobile, and meanwhile reduce the system cost.

Description

A car start-stop system capable of assisting and recovering braking energy

technical field

The invention belongs to the scope of automobile control devices, in particular to an automobile start-stop system, in particular to a start-stop system which can provide boost to the engine and recover the braking energy of the automobile.

Background technique

With the rapid increase in ownership, the energy consumption and emission problems of automobile engines have become increasingly prominent. Companies such as Bosch in Germany have introduced a start-stop system, which increases the engine starting speed by increasing the torque of the starter motor, and realizes the automatic shutdown function at idling speed to reduce fuel consumption and emissions during short-term parking.

However, the function of the existing start-stop system is not complete, and there are still some deficiencies, such as: frequent starting of the engine needs to be matched with high-performance batteries, which increases the cost; the short-term high-current charging capacity of the battery is limited, and it is difficult to effectively recover the braking energy of the vehicle; The power of the motor system powered by the voltage battery is too small to provide effective boost for the engine.

Contents of the invention

The object of the present invention is to provide an automobile start-stop system which can recover braking energy, effectively improve battery life and provide short-term power assistance for the engine.

The present invention adopts following technical scheme:

The car start-stop system that can assist and recover braking energy is characterized in that it includes a BSG unit composed of a battery, a motor and a motor controller, a super capacitor, a one-way step-down converter, a starter, and a start-stop system controller; in:

The output port of the unidirectional buck converter is connected to the battery and the starter at the same time; the input port of the unidirectional buck converter is connected to the supercapacitor and the DC terminal of the motor controller in the BSG unit at the same time; the motor in the BSG unit is an AC motor , connected to the AC terminal of the motor controller; the motor is an electric/power generation integrated motor connected to the engine through a belt, the motor and the motor controller constitute a BSG unit, and the motor controller can transmit electric energy in both directions; the start-stop system controller is separated through the bus Connect with motor controller and unidirectional buck converter.

The unidirectional step-down converter has the step-down capability from its input port to the output port direction, and the input voltage V _cap of its input port=V _bat +X, wherein V _bat is the output port voltage, X is the input port and Output port voltage difference; the unidirectional buck converter also has a non-step-down mode, at this time, the output port voltage V _bat and the input port voltage V _cap will not affect each other, and there is no energy exchange between the two ports.

When the system is working normally, the voltage of the supercapacitor is equal to the voltage V _cap of the input port, and the voltage of the battery is equal to the voltage V _bat of the output port, that is, the voltage of the super capacitor is higher than the voltage of the battery, and the difference between the two is the voltage difference X between the input port and the output port; The DC port output voltage of the motor controller ranges from 0 to V _bat +X.

The start-stop system controller sends control commands to the motor controller and the unidirectional step-down converter to determine the working modes of the two, and then realizes the energy flow control in the start-stop system.

The working process of the system of the present invention is as follows:

When the engine is cold started, the battery supplies power to the starter, the one-way buck converter works in non-buck mode, and there is no energy exchange between the BSG unit and the supercapacitor.

When the battery energy storage is insufficient for normal charging, the supercapacitor charges the battery through the one-way step-down converter; there is no energy exchange between the battery and the starter, and there is no energy exchange between the starter and the one-way step-down converter.

When the engine is hot started, the supercapacitor supplies power to the motor through the motor controller in the BSG unit, and the motor is in electric running mode; the one-way buck converter works in non-buck mode, and there is no energy exchange between the battery and the starter.

In overtaking and short-term climbing conditions, the car needs to be driven with high torque. At this time, the motor works in an electric state to provide power for the engine. The energy flow direction of the boosting process is the same as that of the engine hot start process, but the speed of the motor is higher and the output power is higher during the boosting process, so more energy is required from the super capacitor.

When the car brakes, the BSG unit charges the supercapacitor, and at the same time, the BSG unit charges the battery through the one-way buck converter; there is no energy exchange between the battery and the starter, and there is no energy exchange between the starter and the one-way buck converter. energy exchange.

When the energy storage of the supercapacitor is insufficient and normal charging, the motor in the BSG unit works in the power generation state, and the supercapacitor is charged by the motor controller until the supercapacitor voltage reaches V _bat +X; the unidirectional step-down converter works in the non-step-down mode , there is no energy exchange between the battery and the starter.

The beneficial effects of the present invention are as follows: the supercapacitor undertakes the function of charging and discharging with a large current, and the battery does not need to be discharged with a large current except for the cold start process, which can prolong the life of the battery; only the starter and the battery are used for high-current discharge during the cold start, which is currently widely used Ordinary starters and batteries can meet the requirements of use, which helps to reduce system costs; supercapacitors have an enlarged operating voltage range, strong energy storage capacity, and can be matched with large-capacity motors. In addition to realizing the engine start and stop functions, they can also effectively recycle cars braking energy, and can provide auxiliary power for the engine; the required one-way buck converter capacity is small, which is beneficial to reduce system cost.

Description of drawings

Figure 1 is a structural diagram of a vehicle start-stop system that can assist and recover braking energy.

Fig. 2 is a schematic diagram of the energy flow of the start-stop system during the engine cold start process.

Fig. 3 is a schematic diagram of the energy flow during the supercapacitor charging process.

Fig. 4 is a schematic diagram of energy flow in the battery charging process.

Fig. 5 is a schematic diagram of energy flow during engine hot start and power assist process.

Fig. 6 is a schematic diagram of energy flow in the braking process.

In the figure: 1. battery; 2. BSG unit; 3. supercapacitor; 4. unidirectional step-down converter; 5. motor; 6. motor controller; 7. starter; 8. start-stop system controller.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the present invention will be further described:

The structure of the car start-stop system that can assist and recover braking energy is shown in Figure 1. It consists of a battery 1, a BSG unit 2 including a motor 5 and a motor controller 6, a super capacitor 3, a one-way step-down converter 4, and a starter 7. The start-stop system is composed of 8 controllers.

The output port of the unidirectional step-down converter 4 is connected to the battery 1 and the starter 7 at the same time; the input port of the unidirectional step-down converter 4 is connected to the supercapacitor 3 and the DC terminal of the motor controller 6 in the BSG unit 2 at the same time; the BSG The motor 5 in the unit 2 is an AC motor, which is connected to the AC terminal of the motor controller 6; the start-stop system controller 8 is respectively connected to the motor controller 6 and the unidirectional step-down converter 4 through the bus.

When the system works normally, the voltage V _cap of the supercapacitor 3 is higher than the voltage V _bat of the battery 1 , and the difference between the two is X, that is, V _cap =V _bat +X. For example, for a 12V battery 1, the working voltage of the supercapacitor 3 can be selected to be 18V-30V.

The unidirectional step-down converter 4 has a step-down capability from its input port to its output port, the voltage of its input port is V _bat +X, and the voltage of its output port is V _bat . The unidirectional step-down converter 4 also has a non-step-down mode. At this time, the output port voltage V _bat and the input port voltage V _cap will not affect each other, and there is no energy exchange between the two ports.

The motor 5 is a motor/generator integrated motor (BSG) connected to the engine through a belt, and the motor controller 6 can transmit electric energy bidirectionally. The output voltage range of the DC port of the motor controller 6 is 0-V _bat +X.

The start-stop system controller 8 sends control commands to the motor controller 6 and the unidirectional step-down converter 4 to determine the working modes of the two, so as to realize energy flow control in the start-stop system.

When the engine starts cold, the energy flow is shown in Figure 2. The battery 1 supplies power to the starter 7, the unidirectional step-down converter 4 works in a non-step-down mode, and there is no energy exchange between the BSG unit 2 and the supercapacitor 3 .

When the energy storage of the supercapacitor 3 is insufficient for normal charging, the energy flow is as shown in Figure 3. The motor 5 in the BSG unit 2 works in the power generation state, and the supercapacitor 3 is charged by the motor controller 6 until the voltage of the supercapacitor 3 reaches V _bat +X; There is no energy exchange with the starter 7.

When the storage battery 1 is insufficient for normal charging, the energy flow is shown in Figure 4. The supercapacitor 3 charges the battery 1 through the one-way step-down converter 4, and the one-way step-down converter 4 works in a step-down state; there is no energy exchange between the battery 1 and the starter 7, and the starter 7 and the one-way step-down conversion There is also no energy exchange between devices 4.

When the engine is hot started, the energy flow is shown in Figure 5. The supercapacitor 3 supplies power to the motor 5 through the motor controller 6 in the BSG unit 2, and the motor 5 is in the electric operation mode; the unidirectional step-down converter 4 works in the non-step-down mode, and there is no energy exchange between the battery 1 and the starter 7 .

When boosting the engine, the energy flow is shown in Figure 5, which is the same as the energy flow during the engine hot start process.

When the car brakes, the energy flow is shown in Figure 6. The motor 5 in the BSG unit 2 works in the power generation state, and the motor controller 6 operates in the rectification state; the BSG unit 2 charges the supercapacitor 3, and at the same time, the BSG unit 2 charges the battery 1 through the unidirectional step-down converter 4, and the unidirectional The step-down converter 4 works in a step-down state; there is no energy exchange between the battery 1 and the starter 7 , and there is no energy exchange between the starter 7 and the one-way step-down converter 4 .

Claims (5)

1. can power-assisted and reclaim the automobile start stop system of braking energy, it is characterized in that: include BSG unit, super capacitor, unidirectional buck converter, starter, start stop system controller that storage battery, motor and electric machine controller form; Wherein:

The output port of unidirectional buck converter is connected with starter with storage battery simultaneously; The input port of unidirectional buck converter is connected with the DC terminal of electric machine controller in super capacitor, BSG unit simultaneously; Motor in BSG unit is alternating current dynamo, is connected with the interchange end of electric machine controller; Motor is electronic/generating integrated motor being connected with driving engine by belt, and motor and electric machine controller form BSG unit, and electric machine controller can bi-directional electric energy; Start stop system controller is connected with electric machine controller and unidirectional buck converter respectively by bus.

2. according to claim 1 can power-assisted and reclaim the automobile start stop system of braking energy, it is characterized in that: described unidirectional buck converter has the step-down ability to output port direction by its input port its input port voltage V _cap=V _bat+ X, wherein V _batfor output port voltage, X is input port and output port voltage difference; Unidirectional buck converter also has non-decompression mode, now, and output port voltage V _batwith input port voltage V _capcan not influence each other, noenergy exchange between two ports.

3. according to claim 1 can power-assisted and reclaim the automobile start stop system of braking energy, it is characterized in that: during described system normal operation, super capacitor voltage equals input port voltage V _cap, battery tension equals output port voltage V _bat, super capacitor voltage is higher than battery tension, and the two difference is input port and output port voltage difference X; Electric machine controller DC port output voltage range is 0～V _bat+ X.

4. according to claim 1 can power-assisted and reclaim the automobile start stop system of braking energy, it is characterized in that: described start stop system controller is determined the mode of operation of the two to electric machine controller and unidirectional buck converter respectively by sending controling instruction, and then realize the flow direction of energy in start stop system and control; During engine cold starting, storage battery is starter power supply; When batteries to store energy is not enough, super capacitor is battery charge by unidirectional buck converter; When engine thermal starting and power-assisted, the electric machine controller of super capacitor in BSG unit is motor power supply; During automobile brake, BSG charges to super capacitor unit, and meanwhile, BSG unit charges a battery through unidirectional buck converter.

5. according to claim 1 can power-assisted and reclaim the automobile start stop system of braking energy, it is characterized in that: when described super capacitor energy-storage deficiency charges normal, motor in BSG unit is super capacitor charging through electric machine controller, until super capacitor voltage reaches V _bat+ X.

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