Autonomous charging management system for electric vehicles

• US 9,616,763 B2
• Filed: 03/06/2015
• Issued: 04/11/2017
• Est. Priority Date: 06/12/2014
• Status: Expired due to Fees

• Current Assignee: King Fahd University Of Petroleum And Minerals
• Original Assignee: King Fahd University Of Petroleum And Minerals
• Inventors: Akhtar, Ghous Muhammad Asim, Al-Awami, Ali Taleb
• Primary Examiner(s): DIAO, M BAYE
• Application Number:
  US14/641,249
• Publication Number:
  US 20160257216A1
• Time in Patent Office: 767 Days
• Field of Search: 320109, 701 22
• CPC Class Codes: B60L 53/665 Methods related to measuring, billing or payment
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/167 Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 30/14 Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing

Abstract

The autonomous charging management system for electric vehicles utilizes a voltage feedback control structure that compares the system voltage at the point of charging against a reference, while also taking into account the EV battery state of charge (SOC). A proportional control structure reduces the EV charging as the system voltage approaches the reference. Moreover, the control structure does not require any communication between the EV and the utility.

Claims

1. An autonomous charging management system for electric vehicles (EVs), comprising:

means for tracking the value of a daily minimum voltage V_min,d,i at each EV point of charging (POC_i);

for each point of charging (POC_i), a proportional controller regulating power draw PD_i by an EV connected at the point of charging (POC_i), the proportional controller having a SOC-dependent fair charging gain constant K_p set between (K_p≅

2000) and (K_p≅

4000);

means for formulating an average using a plurality of values of the daily minimum voltage V_min,d,i;

means for using the average as a voltage set point for the proportional controller, the voltage set point representing a voltage reference, V_ref,i, for the i^th EV characterized by the relation;

2. The autonomous charging management system for electric vehicles according to claim 1, wherein the proportional controller further comprises means for regulating a charging rate, ID_i over a wide range of nodal voltage levels according to a formula characterized by the relation:

ID_i=K_p,i*(V_i−

V_ref,i),

where K_p,i is the proportional control gain for the i^th EV, V_ref,i is the reference voltage level for the i^th EV in per unit (pu), and V_i is the actual real-time voltage in p.u. at the charging point.

3. The autonomous charging management system for electric vehicles according to claim 2, wherein the proportional controller power draw regulation further comprises means for adjusting the power draw PD_i for charging the i^th EV according to a formula characterized by the relation:

4. The autonomous charging management system for electric vehicles according to claim 1, further comprising for a node with balanced loads, means for adding initial SOCs for every N charging EVs per phase, the resultant three lumped SOCs being averaged out for nodes with balanced loads.

5. The autonomous charging management system for electric vehicles according to claim 1, further comprising for a node with unbalanced loads, means for lumping together all EVs on each phase charging on said node into a super EV, the initial SOC of the super EV being obtained by adding up the initial SOCs of the individual EVs at that phase.

6. The autonomous charging management system for electric vehicles according to claim 1, further comprising a power draw rate limiter applied to the EV power draw signal, PD_i, wherein any possible undesirable oscillations are suppressed in the controller response.

7. The autonomous charging management system for electric vehicles according to claim 6, wherein the power draw rate limiter is operable using a rate limit of between 5% and 50%.