Multi-functional storage battery charging and discharging device and control method thereof

Abstract

The invention discloses a multi-functional storage battery charging and discharging device and a control method thereof. The device adopts two-stage transformation. A front-stage unit adopts a three-phase PWM rectifier to obtain a DC-side voltage, the grid-side access current harmonics is reduced, the power factor is improved, and the energy loss is reduced; a rear-stage unit uses an interleaved parallel bidirectional half-bridge converter to greatly reduce the output filter inductance. The three-phase PWM rectifier adopts a double closed-loop control strategy of the voltage outer loop and thecurrent inner loop to realize high-precision control of the DC bus voltage and high-power factor control of the grid-side current; when the bidirectional half-bridge converter controls the output voltage, the double closed-loop control strategy of the voltage outer loop and the current inner loop is adopted to use the single loop control of the inner current loop during control of the output current; when a storage battery is charged, the control current is positive, and when the storage battery is discharged, the control current is negative; and when more power is required, the output ends of the two devices are switched to work in series or in parallel through a switch.

Description

technical field [0001] The invention belongs to the technical field of battery charging and discharging, and in particular relates to a multifunctional battery charging and discharging device and a control method thereof. Background technique [0002] As an energy storage device, the battery has the advantages of stable voltage, reliable power supply, and convenient movement. It is widely used in various sectors of the national economy, such as railways, post and telecommunications, ports, and power systems. The charging and discharging technology of the battery is born with the battery, and has a close relationship with the development and application of the battery. The performance of the charging and discharging device directly affects the technical state and service life of the battery, and determines the degree of pollution to the grid during discharge. [0003] At present, the high-power battery charging device commonly used in China is mainly the thyristor rectifier ...

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Problems solved by technology

However, in practical applications, the pulsation component of the output current is relatively large, which easily causes the battery electrolyte to heat up and evaporate. In addition, the power factor of the grid side is low, the harmonic pollution is serious, and the failure rate is high.

[0004] For the discharge device, phase-controlled active inverter battery discharge device or resistance discharge device is mostly used, among which: the phase-controlled active discharge device has the disadvantages of large volume and noise, low output power factor of the AC side, and serious pollution to the power grid; Although the resistance discharge device is simple in structure and low in cost, it is difficult to control the discharge current, and the power loss is large, so it is difficult to meet the requirement of constant current discharge of the battery.

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