CN106218440B - A kind of power intelligent of charging equipment adjusts circuit and method - Google Patents

Abstract

The invention discloses a power intelligent adjustment circuit and method of charging equipment. Firstly, the SOC of the state of charge of the electric vehicle and the load of the electric vehicle are calculated, and the load curve is drawn; by drawing the load curves of multiple electric vehicles of the same type, it is judged whether the load curve converges , if the load curve converges, then output the load curve, if not, repeat the above operations; determine the maximum output power of the entire charging station according to the electric vehicle load curve, and each terminal charging device adopts the analytic hierarchy process according to the state of charge SOC of the electric vehicle Establish a decision-making model, divide the charging process into three stages: energy replenishment stage, power maintenance stage, and small current replenishment stage, and dynamically allocate the power of each charging port. The invention effectively predicts the charging load of the electric vehicle, makes full use of the charger to realize orderly charging control, ensures the flexible and fast charging of the electric vehicle, and simultaneously takes into account regional load monitoring.

Description

A power intelligent adjustment circuit and method for charging equipment

technical field

The invention belongs to the field of electric vehicles, and in particular relates to an intelligent power adjustment method for charging equipment.

Background technique

Electric vehicles refer to vehicles powered by batteries, fuel cells or supercapacitors, all or part of which are driven by electric motors. They are the fusion product of electrification and automobiles. Electric vehicles can be broadly divided into the following three types, namely hybrid electric vehicles, fuel cell electric vehicles and pure electric vehicles. A hybrid electric vehicle refers to a vehicle that is equipped with more than two power sources (such as batteries, fuel cells, internal combustion engines, etc.), including motor-driven vehicles that comply with road traffic safety regulations. At present, the plug-in hybrid electric vehicle is widely used to drive the electric motor with the battery after it is fully charged. After the battery on the vehicle is used up, the engine on the vehicle consumes oil to drive the generator to generate electricity to charge the battery, and the electric motor continues to be driven by the battery. The pure electric mileage of the hybrid electric vehicle is short, and it does not get rid of the dependence on oil resources. It is a transitional model in the development of the electric vehicle industry. The characteristics of fuel cell electric vehicles are: the electric energy of the power battery comes from the chemical energy generated by the electrochemical means of fuel and oxidant, the electrochemical reaction process of the fuel cell will not produce harmful substances, and has high energy conversion efficiency. Pure electric vehicles are vehicles that are powered entirely by rechargeable batteries (such as lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, etc.). It provides electric energy to the motor through the battery to drive the motor to drive. It is a "zero emission" car and is considered to be the most ideal means of transportation at present.

Electric vehicles have incomparable advantages over traditional vehicles in terms of energy saving and emission reduction, curbing climate warming and ensuring oil supply security, etc., and have attracted extensive attention from governments, automobile manufacturers and energy companies in various countries. The ever-increasing battery equipment, charging technology and charging facilities also promote the continuous popularization of electric vehicles. Studies have shown that at a medium speed of development, by 2020, 2030 and 2050, the proportion of electric vehicles to the total number of vehicles in the United States will reach 35%, 51% and 62%, respectively. my country has also formulated a development plan suitable for the national conditions to promote the industrialization of electric vehicles and improve the integration of vehicle networks (grids). Since 2014, the State Council and relevant ministries and commissions have issued a number of incentive policies such as "Guiding Opinions on Accelerating the Promotion and Application of New Energy Vehicles" and "Guiding Opinions on Accelerating the Construction of Electric Vehicle Charging Infrastructure" to clearly accelerate the construction of charging facilities and give charging facilities Build rewards. As of May 2016, the state and local governments have issued a total of 183 incentive policies related to new energy vehicles, effectively promoting the development of electric vehicles and charging and swapping industries. Under the strong promotion of policies, the production and sales of new energy vehicles in my country have shown explosive growth in recent years. According to statistics from the National Bureau of Statistics, the output of new energy vehicles in May was 54,000, a year-on-year increase of 92.9%. In terms of accumulation, the output of new energy vehicles from January to May was 219,000, a year-on-year increase of 88.8%.

The large-scale use of electric vehicles and the connection of charging loads to the grid will have a profound impact on the planning and operation of the power system and the operation of the power market. Due to the influence of many factors, the charging load has complex characteristics. As far as a single vehicle is concerned, it is mainly determined by the user's travel needs, and is also affected by factors such as user habits and equipment characteristics. As far as the regional power system is concerned, it is also affected by the scale of the number of electric vehicles and the degree of perfection of charging facilities. Due to the uncertainty and mutual differences of user demand and user behavior, the charging load has certain randomness and dispersion. The load increase caused by the charging load will put forward higher demands on the power generation, transmission and distribution capacity of the power system; while the charging load affects the loss and voltage level of the distribution network, it will also affect the three-phase load balance, The life of the distribution transformer will be affected, and it will also cause problems such as local overload of the distribution network load; the existence of charging harmonics will also affect the power quality of the distribution network. In terms of electricity market operations, electric vehicles and electric vehicle aggregators will become new market participants, participating in market bidding and providing auxiliary services; the huge number and decentralized nature of electric vehicles have transformed the market operation mechanism from centralized to decentralized. The stable operation of the complex electricity market with decentralized mechanisms has also become a concern. The energy storage capacity of the battery enables users to have certain flexibility in choosing the charging time, and the charging load has certain controllability. Preliminary studies have shown that proper charging control can not only suppress and eliminate the adverse impact of electric vehicles on the grid, but also support the operation of the grid, and the benefits of load scheduling have initially emerged. In particular, the proposal of V2G (vehicle-to-grid) technology makes it possible to use electric vehicle energy storage resources in an average of up to 96% of idle time, adjust the charging and discharging process, promote the absorption of renewable energy power, and provide auxiliary services for the grid.

Therefore, it is necessary to grasp the power demand and energy demand characteristics of electric vehicle charging, study the effective prediction of electric vehicle charging load in two dimensions of time and space, and provide a basis for the management of electric vehicle charging distribution.

Contents of the invention

Purpose of the invention: In order to solve the problem of charging distribution management of multiple electric vehicles with different powers existing in the prior art, the present invention provides an intelligent power adjustment method for charging equipment.

Technical solution: an intelligent power adjustment method for charging equipment, comprising the following steps:

(1) Extract the initial charging time of the electric vehicle, calculate the charging time according to the initial charging time, extract the daily mileage of the electric vehicle, calculate the SOC of the electric vehicle's state of charge, calculate the load of the electric vehicle based on the Monte Carlo method, and draw the load curve;

(2) According to step (1), draw the load curves of multiple electric vehicles of the same type, and judge whether the load curves converge. If the load curves converge, output the load curves. If not, repeat the operation step (1);

(3) Determine the maximum output power of the entire charging station according to the electric vehicle load curve, and each terminal charging device establishes a decision-making model based on the state of charge SOC of the electric vehicle using the analytic hierarchy process. The decision-making model includes the energy supplement stage in the charging process 1. Power maintenance stage and small current supplement stage. The three stages dynamically allocate the power of each charging port.

A power intelligent adjustment circuit for charging equipment, characterized in that it includes a decision model module, a charging equipment power adjustment main loop and a power configuration control loop, and the decision model module includes an energy supplement stage, a power maintenance stage and a small In the current supplement stage, the power of each charging port is dynamically allocated in three stages; the main circuit of the charging device power adjustment includes multiple charging units, an automatic transfer switch connected to the charging unit, and a charging port, and the automatic transfer between multiple charging units Switch connection; the power configuration control loop includes a plurality of parallel relays, and the relays can be switched to one-side remote control and two-side remote control of the corresponding automatic transfer switch.

Beneficial effects: The power intelligent adjustment method of charging equipment provided by the present invention solves the problem of charging multiple electric vehicles with different powers at the same time and space, and at the same time takes into account regional load monitoring. The control provides a basis; especially when all charging at the maximum power in the energy replenishing stage and power maintaining stage, and there is surplus charging power available for distribution, the electric vehicles in the small current replenishing stage are allocated power so that multiple vehicles with different power When electric vehicles are charged at the same time and space, the charging power is reasonably allocated to meet the high-efficiency charging operations of multiple electric vehicles at the same time. Effectively predict the charging load of electric vehicles in two dimensions of time and space, so as to facilitate the distributed management of electric vehicle charging.

The power intelligent adjustment circuit of the charging equipment provided by the present invention can reasonably allocate the charging power of different vehicles through the design of the charging equipment power adjustment main circuit and the power configuration control circuit, make full use of the charger, and ensure the flexible and fast charging of electric vehicles .

Description of drawings

Figure 1 is a flow chart for calculating the charging load of electric vehicles based on the Monte Carlo method;

Fig. 2 is a schematic diagram of the main circuit for power regulation of the charging equipment;

FIG. 3 is a schematic diagram of a power configuration control loop.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

The power intelligent adjustment method of the charging device includes the following steps:

(1) As shown in Figure 1, extract the initial charging time of the electric vehicle, calculate the charging time according to the initial charging time, extract the daily mileage of the electric vehicle, calculate the state of charge SOC of the electric vehicle, and calculate the charging time of the electric vehicle based on the Monte Carlo method. Load, to draw a load curve.

(2) According to step (1), draw the load curves of multiple electric vehicles of the same type, and judge whether the load curves converge. If the load curves converge, output the load curves. If not, repeat the operation step (1).

(3) Determine the maximum output power of the entire charging station according to the electric vehicle load curve, and each terminal charging device establishes a decision-making model based on the state of charge SOC of the electric vehicle using the analytic hierarchy process. The decision-making model includes the energy supplement stage in the charging process 1. Power maintenance stage and small current supplement stage. The three stages dynamically allocate the power of each charging port.

When SOC ≤ 90%, it is the energy replenishment stage, which belongs to the energy replenishment stage and is set as the highest priority;

When 90% ≤ SOC ≤ 98%, it is the power maintenance stage, with the goal of maintaining the charging load power regulation capability, the electric vehicles in the energy supplement stage are charged at the maximum power, and the surplus charging power can be intelligently adjusted, which is the power maintenance stage. Phase electric vehicle allocation power, set to medium priority;

When 98% ≤ SOC ≤ 100%, it is the small current supplement stage. This stage is the end of charging, and the electric vehicle is charged with low power. When all are in the energy supplement stage and power maintenance stage, they are charged at the maximum power and there is surplus charging. When power is available for distribution, distribute power to electric vehicles in the small current supplement phase. set to the lowest priority.

Taking the dual-charging port charging equipment with large market demand at present as an example, it includes a decision-making model module, a charging equipment power regulation main circuit and a power configuration control circuit. The decision-making model module includes the energy supplement stage and power maintenance stage in the charging process. and small current supplementary stage, three stages dynamically distribute the power of each charging port; as shown in Figure 2, the charging device power regulation main circuit includes a plurality of charging units, an automatic transfer switch connected with the charging unit and two charging ports , a plurality of charging units are connected through an automatic transfer switch; as shown in Figure 3, the power configuration control loop includes a plurality of parallel relays, and the relays can be switched to one-side remote control and two-side remote control of the corresponding automatic transfer switch, and also Includes a master switch that controls multiple relays.

The invention can solve the problem of simultaneous charging of multiple electric vehicles with different powers, can make full use of chargers to realize orderly charging control, ensure flexible and fast charging of electric vehicles, and simultaneously take into account regional load monitoring.

Claims (5)

1. A method for intelligent power regulation of a charging device, comprising the following steps: (1) Extract the initial charging time of the electric vehicle, calculate the charging time according to the initial charging time, extract the daily mileage of the electric vehicle, calculate the SOC of the electric vehicle's state of charge, calculate the load of the electric vehicle based on the Monte Carlo method, and draw the load curve; (2) According to step (1), draw the load curves of multiple electric vehicles of the same type, and judge whether the load curves converge. If the load curves converge, output the load curves. If not, repeat the operation step (1); (3) Determine the maximum output power of the entire charging station according to the electric vehicle load curve, and each terminal charging device establishes a decision-making model based on the state of charge SOC of the electric vehicle using the analytic hierarchy process. The decision-making model includes the energy supplement stage in the charging process 1. Power maintenance stage and small current supplement stage. The three stages dynamically allocate the power of each charging port. 2. The intelligent power adjustment method for charging equipment according to claim 1, wherein the three stages of the charging process in the step (3) specifically include: When SOC ≤ 90%, it is the energy supplement stage, set as the highest priority; When 90% ≤ SOC ≤ 98%, it is the power maintenance phase, set to medium priority; When 98% ≤ SOC ≤ 100%, it is the small current supplementary stage, set to the lowest priority. 3. The power intelligent adjustment method of charging equipment according to claim 2, characterized in that, firstly, charging the electric vehicles in the energy replenishment stage; when all the electric vehicles in the energy replenishment stage are charged with the maximum power, and there is surplus charging When the power is available for allocation, allocate power to the electric vehicles in the power maintenance phase; when all the electric vehicles in the energy supplement phase and power maintenance phase are charged with the maximum power, and there is surplus charging power available for allocation, the electric vehicles in the small current supplement phase Electric vehicles distribute power. 4. A power intelligent adjustment circuit for a charging device, characterized in that it includes a decision model module, a charging device power regulation main loop and a power configuration control loop, and the decision model module includes an energy supplement stage and a power maintenance stage in the charging process and the small current supplement stage, the power of each charging port is dynamically distributed in the three stages; the main circuit of the charging device power adjustment includes a plurality of charging units, an automatic transfer switch connected to the charging unit and a charging port, and the charging units are connected through The automatic transfer switch is connected; the power configuration control loop includes a plurality of parallel relays, and the relays can be switched to one-side remote control and two-side remote control of the corresponding automatic transfer switch. 5 . The intelligent power adjustment circuit for charging equipment according to claim 4 , further comprising a master switch for controlling a plurality of relays. 6 .