Intelligent reactive power compensation device for charging station

Abstract

An intelligent reactive power compensation device for a charging station comprises a load connected with a system side through a transformer, the load is further connected with the reactive power compensation device, the reactive power compensation device comprises a power device module, a filter inductor and a connecting reactor which are connected in sequence, and the connecting reactor is connected with the load. The power device module is further connected with the supporting capacitor in parallel, and a filter capacitor is connected between the filter inductor and the connecting reactor and connected to a zero line. The utility model provides an intelligent reactive power compensation device for a charging station, which is used as dynamic reactive power compensation equipment capable of quickly responding, is suitable for a system containing an impact load, such as a quick charging station containing a large number of randomly accessed quick charging loads, and can provide real-time synchronous compensation for a high-power quick charging station.

Description

Technical Field

[0001] The utility model relates to the technical field of reactive power compensation in power systems, in particular to an intelligent reactive power compensation device for charging stations. Background Technique

[0002] Most of the existing reactive power compensation devices are for conventional power stations, and there is a relative lack of research on the application of compensation devices for fast charging stations. Moreover, the influence of the fast charging load penetration rate has not been systematically considered, and there is a lack of research and analysis on the charging scenarios of charging stations. Therefore, how to deeply analyze the charging scenarios of fast charging stations and the node voltage levels considering the influence of the fast charging load penetration rate, and apply appropriate compensation devices to fast charging stations under different load penetration rate scenarios to improve the voltage quality of fast charging stations and the economic efficiency of operation is another challenge faced by the research on the application of compensation devices for charging stations.

[0003] In the prior art, it is not considered how to coordinately utilize the reactive power output capabilities of electric vehicle charging piles and reactive power compensation devices to compensate and control when the node voltage of a single point or some charging pile nodes is unstable, so as to quickly control the unstable node voltage within a safe range. This will greatly weaken the economic flexibility of the large-scale construction and operation of charging stations and the adjustable ability of the node voltage for the access range, and will increase the charging cost of electric vehicles. Summary of the Invention

[0004] The technical problem to be solved by the utility model is to provide an intelligent reactive power compensation device for charging stations, which solves the problem of low power quality caused by different load penetration rate scenarios in fast charging stations, including harmonic problems and grid current imbalance problems.

[0005] To solve the above technical problem, the technical solution adopted by the utility model is: an intelligent reactive power compensation device for charging stations, including a load connected to the system side through a transformer, and the load is also connected to a reactive power compensation device. The reactive power compensation device includes a power device module, a filter inductor, and a connecting reactor connected in sequence. The connecting reactor is connected to the load;

[0006] The power device module is also connected in parallel with a support capacitor. A filter capacitor is connected between the filter inductor and the connecting reactor, and the filter capacitor is connected to the neutral line.

[0007] Preferably, a circuit breaker is provided between the load and the connecting reactor.

[0008] Preferably, a compensation-side voltage transformer and a compensation-side current transformer are provided between the power device module and the filtering inductor, a load-side voltage transformer and a load-side current transformer are provided between the load and the transformer, and a system-side voltage transformer and a system-side current transformer are provided on the system side; the compensation-side voltage transformer, the compensation-side current transformer, the load-side voltage transformer, the load-side current transformer, the system-side voltage transformer and the system-side current transformer are electrically connected to a controller, and the controller is also electrically connected to the power device module.

[0009] Preferably, the controller includes a DSP processor. The compensation-side voltage transformer, the compensation-side current transformer, the load-side voltage transformer, the load-side current transformer, the system-side voltage transformer and the system-side current transformer are electrically connected to the input end of the DSP processor, and the power device module is electrically connected to the output end of the DSP processor.

[0010] The utility model provides an intelligent reactive power compensation device for a charging station. As a dynamic reactive power compensation device that can respond quickly, it is applicable to systems with impact loads, such as fast charging stations with a large number of randomly connected fast charging loads, and can provide real-time synchronous compensation for high-power fast charging stations. Brief Description of the Drawings

[0011] The following further describes the utility model in conjunction with the drawings and embodiments:

[0012] Figure 1 It is a structural schematic diagram of the utility model. Detailed Embodiment

[0013] As Figure 1 shown, an intelligent reactive power compensation device for a charging station includes a load 4 connected to the system side through a transformer. The load 4 is also connected to the reactive power compensation device. The reactive power compensation device includes a power device module 5, a filtering inductor 8, and a connecting reactance 10 connected in sequence. The connecting reactance 10 is connected to the load.

[0014] The power device module 5 is also connected in parallel with a support capacitor 3. A filtering capacitor 9 is connected between the filtering inductor 8 and the connecting reactance 10, and the filtering capacitor 9 is connected to the neutral line. The power device module 5 includes IGBT modules, and each IGBT module is a half-bridge module. Four IGBT modules form a three-phase four-wire system. The support capacitor, as an element for voltage support of the intelligent reactive power compensation device, uses a film capacitor with a voltage rating of 1700V.

[0015] Preferably, a circuit breaker 11 is provided between the load 4 and the connecting reactance 10.

[0016] Preferably, a compensation side voltage transformer 6 and a compensation side current transformer 7 are provided between the power device module 5 and the filter inductor 8, a load side voltage transformer 12 and a load side current transformer 13 are provided between the load 4 and the transformer, and a system side voltage transformer 14 and a system side current transformer 15 are provided on the system side; the compensation side voltage transformer 6, the compensation side current transformer 7, the load side voltage transformer 12, the load side current transformer 13, the system side voltage transformer 14 and the system side current transformer 15 are electrically connected to the controller 1, and the controller 1 is also electrically connected to the power device module 5.

[0017] Preferably, the controller 1 includes a DSP processor 2. The compensation side voltage transformer 6, the compensation side current transformer 7, the load side voltage transformer 12, the load side current transformer 13, the system side voltage transformer 14 and the system side current transformer 15 are electrically connected to the input end of the DSP processor 2, and the power device module 5 is electrically connected to the output end of the DSP processor 2.

[0018] The DSP is used for calculating sampling, and the sampling is realized through an AD chip, and the system three-phase voltage, the device three-phase voltage, the load three-phase voltage, the system three-phase current, the device three-phase current, the device three-phase voltage, the zero-sequence current, etc. are collected.

[0019] The sampling voltage transformer and the current transformer are used for signal conversion, and convert the large voltage and large current into a 2 mA current signal required by the edge control.

[0020] The filter circuit includes a connecting reactor, a filter reactor, a filter capacitor, etc. By calculation, the high-order harmonics generated by the on-off of the power module are filtered out to ensure that the harmonic content of the output current meets the national standard.

[0021] During use, the controller 1 calculates the reactive power and harmonic current data required for branch compensation through the signals of the load side voltage transformer 12, the load side current transformer 13, the system side voltage transformer 14 and the system side current transformer 15 collected by the AD, outputs a PWM control signal after being processed by the DSP, controls the power device module 5 to switch, and outputs a corresponding voltage pulse signal. In this process, the support capacitor 3 plays a voltage support role. The voltage pulse signal output by the power device module 5 is filtered by the filter reactor 8 and the filter capacitor 9 to filter out high-order harmonics and is connected to the system side through the connecting reactor 10 and the circuit breaker 11 for compensation. Among them, the currents measured by the compensation side voltage transformer 6 and the compensation side current transformer 7 are sent to the controller 1 through the AD for closed-loop control to ensure the consistency of the output current and the system required current.

[0022] This device can improve the power factor of the fast charging station power supply system and reduce the power loss inside the fast charging station. In the case of three-phase imbalance in the in-station system, the active and reactive loads are balanced in time, and the unbalance degree of the charging system is improved.

[0023] The above embodiments are only the preferred technical solutions of the present utility model and should not be regarded as limitations on the present utility model. The protection scope of the present utility model should be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, the equivalent replacement improvements within this scope are also within the protection scope of the present utility model.

Claims

1. An intelligent reactive power compensation device for a charging station, including a load (4) connected to the system side via a transformer, characterized in that: The load (4) is also connected to a reactive power compensation device, which includes a power device module (5), a filter inductor (8), and a connecting reactance (10) connected in sequence. The connecting reactance (10) is connected to the load; The power device module (5) is also connected in parallel with a support capacitor (3). A filter capacitor (9) is connected between the filter inductor (8) and the connecting reactance (10), and the filter capacitor (9) is connected to the neutral line.

2. The intelligent reactive power compensation device for a charging station according to claim 1, characterized in that: A circuit breaker (11) is provided between the load (4) and the connecting reactance (10).

3. The intelligent reactive power compensation device for a charging station according to claim 2, characterized in that: A compensation-side voltage transformer (6) and a compensation-side current transformer (7) are provided between the power device module (5) and the filter inductor (8). A load-side voltage transformer (12) and a load-side current transformer (13) are provided between the load (4) and the transformer. A system-side voltage transformer (14) and a system-side current transformer (15) are provided on the system side; the compensation-side voltage transformer (6), the compensation-side current transformer (7), the load-side voltage transformer (12), the load-side current transformer (13), the system-side voltage transformer (14), and the system-side current transformer (15) are electrically connected to a controller (1), and the controller (1) is also electrically connected to the power device module (5).

4. The intelligent reactive power compensation device for a charging station according to claim 3, wherein: The controller (1) includes a DSP processor (2). The compensation-side voltage transformer (6), the compensation-side current transformer (7), the load-side voltage transformer (12), the load-side current transformer (13), the system-side voltage transformer (14), and the system-side current transformer (15) are electrically connected to the input end of the DSP processor (2), and the power device module (5) is electrically connected to the output end of the DSP processor (2).

Images