DC parallel-serial transition electric power system

Abstract

The invention relates to the technical field of supplying electricity to a power utilization device after two groups of direct current power supplies are parallelly or serially connected, in particular to technology of supplying electricity to electric bicycles and electric automobiles, which comprises a direct current parallel-serial connection converter (12), wherein the direct current parallel-serial connection converter (12) is provided with a direct current power supply connection wire (4) and a direct current power supply connection wire (5) which can be connected with a direct current power supply (A13) and a direct current power supply B14, and is provided with a pair of positive and negative conducting wire direct current output connection wires (7) which are connected with a positive connection wire and a negative connection wire of the power utilization device. The technology has the advantages that the technology realizes the conversion of parallel-serial connection only by a switch, and solves common problems of conversion failure and battery short-circuit caused by non-synchronized switches when a plurality of switches realize the conversion of the parallel-serial connection, has a simple structure and reliable work, reduces the damage of heavy current to batteries through the normal parallel low-voltage output of the two groups of direct current power supplies and the serial high-voltage output when needing to be used, reduces the quantity of usable batteries in waste battery packs, reduces the count of rechargeable serial batteries, improves the dischargingefficiency of the batteries, is favorable for the safety due to the adoption of high and low speed staged operation, and can meet different power supply demands at any time.

Description

Technical field [0001] The invention relates to the technical field of connecting two sets of direct current power supplies in parallel or in series to supply power to electrical appliances, in particular to the technology of supplying power to electric bicycles and electric vehicles. Background technique [0002] At present, the well-known electric vehicle DC brushless motor controller is an electrical appliance that only accepts one power input. Because the current power supply used in electric vehicles is a 24V, 36V or 48V DC power pack composed of 12V batteries in series , The service life of 24V battery pack can be as long as 3 to 4 years, and the service life of 36V battery pack can be up to about 2 years, but the voltage of these two battery packs is low, and electric vehicles using these two power packs are weak to start and go uphill. Difficulties and extremely short continuation mileage. Although the 48V battery pack can meet the requirements of electric vehicle start-...

AI Technical Summary

Problems solved by technology

[0002] At present, the known electric vehicle DC brushless motor controller is an electrical appliance that only accepts one power supply input, because the current power supply used on electric vehicles is a 24V, 36V or 48V DC power supply group composed of 12V batteries connected in series. , The service life of the 24V battery pack can be as long as 3 to 4 years, and the service life of the 36V battery pack can reach about 2 years. Difficult, very short mileage

Although the 48V battery pack can meet the requirements of electric vehicle starting, uphill, and continuation mileage, but because the number of single battery packs in series is too large, the probability of difference between the batteries in series increases, which results in The single battery with the smallest capacity is always over-discharged and under-charged, which makes the capacity of a single battery decay too quickly, and the capacity is often lower than 60% of the original capacity in less than a year.

The matching charger must also increase the voltage and power accordingly, which is neither safe nor prone to failure, so a single set of power supply limits the applicability and development of electric vehicles

At present, an electric vehicle controller only controls the output voltage by a speed control handle, the control method is too monotonous and non-staged, and the user often turns the speed control handle to the maximum angle quickly from the start, thereby reducing the speed. Sensitivity and safety vigilance, and the voltage supplied to the motor immediately reaches the upper limit of the input voltage, and at the same time, the power of the motor rises too fast, the current is too large, the motor heats up, and the life of the motor is shortened

[0004] To solve these problems, multiple groups of DC power supplies are required to be converted in parallel and connected in series. However, the commonly used parallel-series conversion method is completed by the cooperation of multiple switches, relays and logic arrays. danger of short circuit

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